Search results for: zinc nanoparticles

Authors: Mathias Schlenk, Susanne Seibt, Sabine Rosenfeldt, Josef Breu, Stephan Foerster

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Thin liquid jets on micrometer scale play an important role in processing such as in fiber fabrication, inkjet printing, but also for sample delivery in modern synchrotron X-ray devices. In all these cases the liquid jets contain solvents and dissolved materials such as polymers, nanoparticles, fibers pigments or proteins. As liquid flow in liquid jets differs significantly from flow in capillaries and microchannels, particle localization and orientation will also be different. This is of critical importance for applications, which depend on well-defined homogeneous particle and fiber distribution and orientation in liquid jets. Investigations of particle orientation in liquid microjets of diluted solutions have been rare, despite their importance. With the arise of micro-focused X-ray beams it has become possible to scan across samples with micrometer resolution to locally analyse structure and orientation of the samples. In the present work, we used this method to scan across liquid microjets to determine the local distribution and orientation of anisotropic particles. The compromise wormlike block copolymer micelles as an example of long flexible fibrous structures, hectorite materials as a model of extended nanosheet structures, and gold nanorods as an illustration of short stiff cylinders to comprise all relevant anisotropic geometries. We find that due to the different velocity profile in the liquid jet, which resembles plug flow, the orientation of the particles which was generated in the capillary is lost or changed into non-oriented or bi-axially orientations depending on the geometrical shape of the particle.

Keywords: anisotropic particles, liquid microjets, reorientation, SAXS

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Authors: Tien S. H. Pham, Peter J. Mahon, Aimin Yu

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The detection of drug molecules by voltammetry has attracted great interest over the past years. However, many drug molecules exhibit poor electrochemical signals at common electrodes which result in low sensitivity in detection. An efficient way to overcome this problem is to modify electrodes with functional materials. Since discovered in 2004, graphene (or reduced graphene oxide) has emerged as one of the most studied two-dimensional carbon materials in condensed matter physics, electrochemistry, and so on due to its exceptional physicochemical properties. Additionally, the continuous development of technology has opened the new window for the successful fabrications of many novel graphene-based nanomaterials to serve in electrochemical analysis. This research aims to synthesize and characterize gold nanoparticle coated beta-cyclodextrin functionalized reduced graphene oxide (Au NP–β-CD–RGO) nanocomposites with highly conductive and strongly electro-catalytic properties as well as excellent supramolecular recognition abilities for the modification of electrodes. The electrochemical responses of ciprofloxacin at the as-prepared nanocomposite modified electrode was effectively amplified was much higher in comparison with that at the bare electrode. The linear concentration range was from 0.01 to 120 µM, with a detection limit of 2.7 nM using differential pulse voltammetry. Thus, Au NP–β-CD–RGO nanocomposite has great potential as an ideal material to construct sensitive sensors for the electrochemical determination of ciprofloxacin or similar antibacterial drugs in the future based on its excellent stability, selectivity, and reproducibility.

Keywords: Au nanoparticles, β-CD, ciprofloxacin, electrochemical determination, graphene based nanomaterials

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Authors: Mallikarjunachari Gangapuram

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The design of stimuli-responsive hydrogel nanocomposite thin films is gaining significant attention in these days due to its wide variety of applications. Soft microrobots, drug delivery, biosensors, regenerative medicine, bacterial adhesion, energy storage and wound dressing are few advanced applications in different fields. In this research work, the nanomechanical properties of composite thin films of 20 microns were tuned by applying homogeneous external DC, and AC magnetic fields of magnitudes 0.05 T and 0.1 T. Polyvinyl alcohol (PVA) used as a matrix material and elliptical hematite nanoparticles (ratio of the length of the major axis to the length of the minor axis is 140.59 ± 1.072 nm/52.84 ± 1.072 nm) used as filler materials to prepare the nanocomposite thin films. Both quasi-static nanoindentation, Nano Dynamic Mechanical Analysis (Nano-DMA) tests were performed to characterize the viscoelastic properties of PVA, PVA+Hematite (0.1% wt, 2% wt and 4% wt) nanocomposites. Different properties such as storage modulus, loss modulus, hardness, and Er/H were carefully analyzed. The increase in storage modulus, hardness, Er/H and a decrease in loss modulus were observed with increasing concentration and DC magnetic field followed by AC magnetic field. Contact angle and ATR-FTIR experiments were conducted to understand the molecular mechanisms such as hydrogen bond formation, crosslinking density, and particle-particle interactions. This systematic study is helpful in design and modeling of magnetic responsive hydrogel nanocomposite thin films for biomedical applications.

Keywords: hematite, hydrogel, nanoindentation, nano-DMA

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Authors: Grzegorz Swiderski, Agata Jablonska-Trypuc, Natalia Popow, Renata Swislocka, Wlodzimierz Lewandowski

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Doxorubicin belongs to the group of anthracycline antitumor antibiotics. Because of the wide spectrum of actions, it is one of the most widely used anthracycline antibiotics, including the treatment of breast, ovary, bladder, lung cancers as well as neuroblastoma, lymphoma, leukemia and myeloid leukemia. Antitumor activity of doxorubicin is based on the same mechanisms as for most anthracyclines. Like the metal ions affect the nucleic acids on many biological processes, so the environment of the metal chelates of antibiotics can have a significant effect on the pharmacological properties of drugs. Complexation of anthracyclines with metal ions may contribute to the production of less toxic compounds. In the framework of this study, the composition of complexes obtained in aqueous solutions of doxorubicin with metal ions (Cu2+ and Zn2+). Complexation was analyzed by spectrophotometric titration in aqueous solution at pH 7.0. The pH was adjusted with 0.02M Tris-HCl buffer. The composition of the complexes found was Cu: doxorubicin (1: 2) and a Zn: doxorubicin (1: 1). The effect of Dox, Dox-Cu and Dox-Zn was examined in MCF-7 breast cancer cell line, which were obtained from American Type Culture Collection (ATCC). The compounds were added to the cultured cells for a final concentration in the range of 0,01µM to 0,5µM. The number of MCF-7 cells with division into living and dead, was determined by direct counts of cells with the use of trypan blue dye using LUNA Logos Biosystems cell counter. ApoTox-Glo Triplex Assay (Promega, Madison, Wisconsin, USA) was used according to the manufacturer’s instructions to measure the MCF-7 cells’ viability, cytotoxicity and apoptosis. We observed a decrease in cells proliferation in a dose-dependent manner. An increase in cytotoxicity and decrease in viability in the ApoTox Triplex assay was also showed for all tested compounds. Apoptosis, showed as caspase 3/7 activation, was observed only in Dox treatment. In Dox-Zn and Dox-Cu caspase 3/7 activation was not observed. This work was financially supported by National Science Centre, Poland, under the research project number 2014/13/B/NZ7/02 352.

Keywords: anticancer properties, anthracycline antibiotic, doxorubicine, metal complexes

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Authors: Nasrin Hosseinzad, Ramin Ghasemi Shayan

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Chemotherapy is the most common procedure in the treatment of advanced cancers but is justsoberlyoperativeand toxic. Nevertheless, the efficiency of chemotherapy is restrictedowing to multiple drug resistance(MDR). Lately, plentiful preclinical experiments have revealedthatPaclitaxel-Curcumin could be an ultimateapproach to converse MDR and synergistically increase their efficiency. The connotationsamongst B-cell-lymphoma2(BCL-2) and multi-drug-resistance-associated-P-glycoprotein(MDR1) consequence of patients forecast the efficiency of paclitaxel-built chemoradiotherapy. There are evidences of the efficacy of paclitaxel in the treatment of surface-transmission of bladder-cell-carcinoma by manipulating bio-adhesive microspheres accomplishedthroughout measured release of drug at urine epithelium. In Genetically-Modified method, muco-adhesive oily constructionoftricaprylin, Tween 80, and paclitaxel group showed slighter toxicity than control in therapeutic dose. Postoperative chemotherapy-Paclitaxel might be more advantageous for survival than adjuvant chemo-radio-therapy, and coulddiminish postoperative complications in cervical cancer patients underwent a radical hysterectomy.HA-Se-PTX(Hyaluronic acid, Selenium, Paclitaxel) nanoparticles could observablyconstrain the proliferation, transmission, and invasion of metastatic cells and apoptosis. Furthermore, they exhibitedvast in vivo anti-tumor effect. Additionally, HA-Se-PTX displayedminor toxicity on mice-chef-organs. Briefly, HA-Se-PTX mightprogress into a respectednano-scale agentinrespiratory cancers. To sum up, Paclitaxel is considered a profitable anti-cancer drug in the treatment and anti-progress symptoms in malignant cancers.

Keywords: cancer, paclitaxel, chemotherapy, tumor

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Authors: Mohammad Javad Afroughi, Farjad Falahati, Larry W. Kostiuk, Jason S. Olfert

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This study investigates the physical characteristics of nanoparticles generated during pyrolysis of methane in hot products of a premixed propane-air flame. An inverted burner is designed to provide a laminar premixed propane-air flame (35 SLPM) then introduce methane co-flow to be pyrolyzed within a closed cylindrical chamber (20 cm in diameter and 68 cm in length). The formed products are discharged through an exhaust with a sampling branch to measure emission characteristics. Carbon particles are sampled with a preheated nitrogen dilution system, and the size distribution of particles formed by pyrolysis is measured by a scanning mobility particle sizer (SMPS). Dilution ratio is calculated using simultaneously measured CO2 concentrations in the exhaust products and diluted samples. Results show that particle size distribution (PSD) is strongly affected by dilution ratio and preheating temperature. PSD becomes unstable at high dilution ratios (typically above 700 times) and/or low preheating temperatures (below 40° C). At a suitable dilution ratio of 55 and preheating temperature up to 70° C, the median diameter of PSD increases from 20 to 220 nm following the introduction of 0.5 SLPM of methane to the propane-air premixed flame. Furthermore, with pyrolysis of methane, total particle number concentration and estimated total mass concentration of particles in the size range of 14 to 700 nm, increase from 1.12 to 3.90 *107 cm-3 and from 0.11 to 154 µg L-1, respectively.

Keywords: laminar premixed flame, methane pyrolysis, nanoparticle physical characteristics, particle mass concentration, particle number concentration, particle size distribution (PSD)

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Authors: Munir Ashraf, Shagufta Riaz

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Personal protective equipment (PPE) and bioactive textiles are highly important for the health care of front line hospital workers, patients, and the general population to be safe from highly infectious diseases. This was even more critical in the wake of COVID-19 outbreak. Most of the medical textiles are inactive against various viruses and bacteria, hence there is a need to wash them frequently to avoid the spread of microorganisms. According to survey conducted by the world health organization, more than 500 million people get infected from hospitals, and more than 13 million died due to these hospitals’ acquired deadly diseases. The market available PPE are though effective against the penetration of pathogens and to kill bacteria but, they are not breathable and active against different viruses. Therefore, there was a great need to develop textiles that are not only effective against bacteria, fungi, and viruses but also are comfortable to the medical personnel and patients. In the present study, waterproof breathable, and biologically active textiles were developed using antiviral and antibacterial nanomaterials. These nanomaterials like TiO₂, ZnO, Cu, and Ag were immobilized at the surface of cotton fabric by using different silane coupling agents and electroless deposition that they retained their functionality even after 30 industrial laundering cycles. Afterwards, the treated fabrics were coated with a waterproof breathable film to prevent the permeation of liquid droplets, any particle or microorganisms greater than 80 nm. The developed cotton fabric was highly active against bacteria and viruses. The good durability of nanomaterials at the cotton surface after several industrial washing cycles makes this fabric an ideal candidate for bioactive textiles used in the medical field.

Keywords: antibacterial, antiviral, cotton, durable

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Authors: Manal Kamel, Sara Maher, Hanan El Baz, Faten Salah, Omar Sayyouh, Zeinab Demerdash

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In the recent COVID 19 pandemic, experts of public health have emphasized testing, tracking infected people, and tracing their contacts as an effective strategy to reduce the spread of the virus. Development of rapid and sensitive diagnostic assays to replace reverse transcription polymerase chain reaction (RT-PCR) is mandatory..Our innovative test strip relying on the application of nanoparticles conjugated to recombinant nanobodies for SARS-COV-2 spike protein (S1) & angiotensin-converting enzyme 2 (that is responsible for the virus entry into host cells) for rapid detection of SARS-COV-2 spike protein (S1) in saliva or sputum specimens. Comparative tests with RT-PCR will be held to estimate the significant effect of using COVID 19 nanobodies for the first time in the development of lateral flow test strip. The SARS-CoV-2 S1 (3 ng of recombinant proteins) was detected by our developed LFIA in saliva specimen of COVID-19 Patients No cross-reaction was detected with Middle East respiratory syndrome coronavirus (MERS-CoV) or SARS- CoV antigens..Our developed system revealed 96 % sensitivity and 100% specificity for saliva samples compared to 89 % and 100% sensitivity and specificity for nasopharyngeal swabs. providing a reliable alternative for the painful and uncomfortable nasopharyngeal swab process and the complexes, time consuming PCR test. An increase in testing compliances to be expected.

Keywords: COVID 19, diagnosis, LFIA, nanobodies, ACE2

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Authors: Arpit Kumar Shrivastava, Subrat Kumar, Rajani Kanta Mohapatra, Priyadarshi Soumyaranjan Sahu

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Computational approaches to predict structure, function and other biological characteristics of proteins are becoming more common in comparison to the traditional methods in drug discovery. Cryptosporidiosis is a major zoonotic diarrheal disease particularly in children, which is caused primarily by Cryptosporidium hominis and Cryptosporidium parvum. Currently, there are no vaccines for cryptosporidiosis and recommended drugs are not effective. With the availability of complete genome sequence of C. hominis, new targets have been recognized for the development of effective and better drugs and/or vaccines. We identified a unique hypothetical epitopic protein in C. hominis genome through BLASTP analysis. A 3D model of the hypothetical protein was generated using I-Tasser server through threading methodology. The quality of the model was validated through Ramachandran plot by PROCHECK server. The functional annotation of the hypothetical protein through DALI server revealed structural similarity with human Transportin 3. Phylogenetic analysis for this hypothetical protein also showed C. hominis hypothetical protein (CUV04613) was the closely related to human transportin 3 protein. The 3D protein model is further subjected to virtual screening study with inhibitors from the Zinc Database by using Dock Blaster software. Docking study reported N-(3-chlorobenzyl) ethane-1,2-diamine as the best inhibitor in terms of docking score. Docking analysis elucidated that Leu 525, Ile 526, Glu 528, Glu 529 are critical residues for ligand–receptor interactions. The molecular dynamic simulation was done to access the reliability of the binding pose of inhibitor and protein complex using GROMACS software at 10ns time point. Trajectories were analyzed at each 2.5 ns time interval, among which, H-bond with LEU-525 and GLY- 530 are significantly present in MD trajectories. Furthermore, antigenic determinants of the protein were determined with the help of DNA Star software. Our study findings showed a great potential in order to provide insights in the development of new drug(s) or vaccine(s) for control as well as prevention of cryptosporidiosis among humans and animals.

Keywords: cryptosporidium hominis, hypothetical protein, molecular docking, molecular dynamics simulation

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Authors: R. Tajau, R. Rohani, M. S. Alias, N. H. Mudri, K. A. Abdul Halim, M. H. Harun, N. Mat Isa, R. Che Ismail, S. Muhammad Faisal, M. Talib, M. R. Mohamed Zin

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Bio-based polymeric materials are increasingly used for a variety of applications, including surface coating, drug delivery systems, and tissue engineering. These polymeric materials are ideal for the aforementioned applications because they are derived from natural resources, non-toxic, low-cost, biocompatible, and biodegradable, and have promising thermal and mechanical properties. The nature of hydrocarbon chains, carbon double bonds, and ester bonds allows various sources of oil (edible), such as soy, sunflower, olive, and oil palm, to fine-tune their particular structures in the development of innovative materials. Palm oil can be the most eminent raw material used for manufacturing new and advanced natural polymeric materials involving radiation techniques, such as coating resins, nanoparticles, scaffold, nanotubes, nanocomposites, and lithography for different branches of the industry in countries where oil palm is abundant. The radiation technique is among the most versatile, cost-effective, simple, and effective methods. Crosslinking, reversible addition-fragmentation chain transfer (RAFT), polymerisation, grafting, and degradation are among the radiation mechanisms. Exposure to gamma, EB, UV, or laser irradiation, which are commonly used in the development of polymeric materials, is used in these mechanisms. Therefore, this review focuses on current radiation processing technologies for the development of various radiation-curable bio-based polymeric materials with a promising future in biomedical and industrial applications. The key focus of this review is on radiation curable palm oil-based products, which have been published frequently in recent studies.

Keywords: palm oil, radiation processing, surface coatings, VOC

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Authors: Garima, S. Pushpavanam

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In this work, analysis of an Aqueous two-phase (polymer-salt) system for extraction of sunset yellow dye is carried out. A polymer-salt ATPS i.e.; Polyethylene glycol-600 and anhydrous sodium sulfate is used for the extraction. Conditions are chosen to ensure that the extraction results in a concentration of the dye in one of the phases. The dye has a propensity to come to the Polyethylene glycol-600 phase. This extracted sunset yellow dye is degraded photo catalytically into less harmful components. The cloud point method was used to obtain the binodal curve of ATPS. From the binodal curve, the composition of salt and Polyethylene glycol -600 was chosen such that the volume of Polyethylene glycol-600 rich phase is low. This was selected to concentrate the dye from a dilute solution in a large volume of contaminated solution into a small volume. This pre-concentration step provides a high reaction rate for photo catalytic degradation reaction. Experimentally the dye is extracted from the salt phase to Polyethylene glycol -600 phase in batch extraction. This was found to be very fast and all dye was extracted. The concentration of sunset yellow dye in salt and polymer phase is measured at 482nm by ultraviolet-visible spectrophotometry. The extraction experiment in micro channels under stratified flow is analyzed to determine factors which affect the dye extraction. Focus will be on obtaining slug flow by adding nanoparticles in micro channel. The primary aim is to exploit the fact that slug flow will help improve mass transfer rate from one phase to another through internal circulation in dispersed phase induced by shear.

Keywords: aqueous two phase system, binodal curve, extraction, sunset yellow dye

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Authors: Mrinalini Amritkar, Disha Patil, Swapna Kulkarni, Sukratu Barve, Suresh Gosavi

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Micro-mixers play an important role in the lab-on-a-chip applications and micro total analysis systems to acquire the correct level of mixing for any given process. The mixing process can be classified as active or passive according to the use of external energy. Literature of microfluidics reports that most of the work is done on the models of steady laminar flow; however, the study of unsteady laminar flow is an active area of research at present. There are wide applications of this, out of which, we consider nanoparticle synthesis in micro-mixers. In this work, we have developed a model for unsteady flow to study the mixing performance of a passive micro mixer for reactants used for such synthesis. The model is developed in Finite Volume Method (FVM)-based software, OpenFOAM. The model is tested by carrying out the simulations at Re of 0.5. Mixing performance of the micro-mixer is investigated using simulated concentration values of mixed species across the width of the micro-mixer and calculating the variance across a line profile. Experimental validation is done by passing dyes through a Y shape micro-mixer fabricated using polydimethylsiloxane (PDMS) polymer and comparing variances with the simulated ones. Gold nanoparticles are later synthesized through the micro-mixer and collected at two different times leading to significantly different size distributions. These times match with the time scales over which reactant concentrations vary as obtained from simulations. Our simulations could thus be used to create design aids for passive micro-mixers used in nanoparticle synthesis.

Keywords: Lab-on-chip, LOC, micro-mixer, OpenFOAM, PDMS

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Authors: Priya Ruban, Thirunavoukkarasu Manikkannan, Sakthivel Ramasamy

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Sulfide is one of the major pollutants of tannery effluent which is mainly generated during the process of unhairing. Recovery of Hydrogen green fuel from sulfide wastewater using photocatalysis is a ‘Cleaner Production Method’, since renewable solar energy is utilized. It has triple advantages of the generation of H2, waste minimization and odor or pollution control. Designing of safe and green photocatalysts and developing suitable solar photoreactor is important for promoting this technology to large-scale application. In this study, green photocatalyst i.e., spinach derived carbon dots (SCDs 5 wt % and 10 wt %)/TiO2 nanocomposite was synthesized for generation of H2 from sulfide wastewater using lab-scale solar photocatalytic reactor. The physical characterization of the synthesized solar light responsive nanocomposites were studied by using DRS UV-Vis, XRD, FTIR and FESEM analysis. The absorption edge of TiO2 nanoparticles is extended to visible region by the incorporation of SCDs, which was used for converting noxious pollutant sulfide into eco-friendly solar fuel H2. The SCDs (10 wt%)-TiO2 nanocomposite exhibits enhanced photocatalytic hydrogen production i.e. ~27 mL of H2 (180 min) from simulated sulfide wastewater under LED visible light irradiation which is higher as compared to SCDs. The enhancement in the photocatalytic generation of H2 is attributed to combining of SCDs which increased the charge mobility. This work may provide new insights to usage of naturally available and cheap materials to design novel nanocomposite as a visible light active photocatalyst for the generation of H2 from sulfide containing wastewater.

Keywords: carbon dots, hydrogen fuel, hydrogen sulfide, photocatalysis, sulfide wastewater

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Authors: P. G. Siddheshwar, T. N. Sakshath

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In the paper we make linear and non-linear stability analyses of Rayleigh-Bénard convection of a Newtonian nanoliquid in a rotating medium (called as Rayleigh-Bénard-Taylor convection). Rigid-rigid isothermal boundaries are considered for investigation. Khanafer-Vafai-Lightstone single phase model is used for studying instabilities in nanoliquids. Various thermophysical properties of nanoliquid are obtained using phenomenological laws and mixture theory. The eigen boundary value problem is solved for the Rayleigh number using an analytical method by considering trigonometric eigen functions. We observe that the critical nanoliquid Rayleigh number is less than that of the base liquid. Thus the onset of convection is advanced due to the addition of nanoparticles. So, increase in volume fraction leads to advanced onset and thereby increase in heat transport. The amplitudes of convective modes required for estimating the heat transport are determined analytically. The tri-modal standard Lorenz model is derived for the steady state assuming small scale convective motions. The effect of rotation on the onset of convection and on heat transport is investigated and depicted graphically. It is observed that the onset of convection is delayed due to rotation and hence leads to decrease in heat transport. Hence, rotation has a stabilizing effect on the system. This is due to the fact that the energy of the system is used to create the component V. We observe that the amount of heat transport is less in the case of rigid-rigid isothermal boundaries compared to free-free isothermal boundaries.

Keywords: nanoliquid, rigid-rigid, rotation, single phase

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Authors: Bartlomiej S. Witkowski, Lukasz Wachnicki, Sylwia Gieraltowska, Rafal Pietruszka, Marek Godlewski

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Zinc oxide is extensively studied II-VI semiconductor with a direct energy gap of about 3.37 eV at room temperature and high transparency in visible light spectral region. Due to these properties, ZnO is an attractive material for applications in photovoltaic, electronic and optoelectronic devices. ZnO nanorods, due to a well-developed surface, have potential of applications in sensor technology and photovoltaics. In this work we present a new inexpensive method of the ultra-fast growth of ZnO nanorods from the aqueous solution. This environment friendly and fully reproducible method allows growth of nanorods in few minutes time on various substrates, without any catalyst or complexing agent. Growth temperature does not exceed 50ºC and growth can be performed at atmospheric pressure. The method is characterized by simplicity and allows regulation of size of the ZnO nanorods in a large extent. Moreover the method is also very safe, it requires organic, non-toxic and low-price precursors. The growth can be performed on almost any type of substrate through the homo-nucleation as well as hetero-nucleation. Moreover, received nanorods are characterized by a very high quality - they are monocrystalline as confirmed by XRD and transmission electron microscopy. Importantly oxygen vacancies are not found in the photoluminescence measurements. First results for obtained by us ZnO nanorods in sensor applications are very promising. Resistance UV sensor, based on ZnO nanorods grown on a quartz substrates shows high sensitivity of 20 mW/m2 (2 μW/cm2) for point contacts, especially that the results are obtained for the nanorods array, not for a single nanorod. UV light (below 400 nm of wavelength) generates electron-hole pairs, which results in a removal from the surfaces of the water vapor and hydroxyl groups. This reduces the depletion layer in nanorods, and thus lowers the resistance of the structure. The so-obtained sensor works at room temperature and does not need the annealing to reset to initial state. Details of the technology and the first sensors results will be presented. The obtained ZnO nanorods are also applied in simple-architecture photovoltaic cells (efficiency over 12%) in conjunction with low-price Si substrates and high-sensitive photoresistors. Details informations about technology and applications will be presented.

Keywords: hydrothermal method, photoresistor, photovoltaic cells, ZnO nanorods

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Authors: Md. Shoffikul Islam, Hongqing Hu

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Reducing trace elements' mobility and bioavailability through amendment addition, especially biochar (BC), is a cost-effective and efficient method to address their toxicity in the soil environment. However, the low molecular weight organic acids (LMWOAs) in the rhizosphere could affect BC's efficiency to stabilize trace metals as the LMWOAs could either mobilize or fix metals in the soils. Therefore, understanding the BC's and LMWOAs' interaction mechanisms on metals stabilization in the rhizosphere is crucial. The present study explored the impact of BC derived from rice husk and citric acid (CA) and the combination of BC and CA on the redistribution of cadmium (Cd), lead (Pb), and zinc (Zn) among their geochemical forms through incubation experiment. The changes of zeta potential and X-ray diffraction (XRD) pattern of BC and BC-amended soils to investigate the probable mechanisms of trace elements' immobilization by BC under the CA attack were also examined. The rice husk BC at 5% (w/w) was mixed with the air-dry soil (an Anthrosols) contaminated with Cd, Pb, and Zn in the plastic pot. The 2, 5, 10, and 20 mM kg-1 (w/v) of CA were added separately into the pot. All the ingredients were mixed thoroughly with the soil. A control (CK) treatment was also prepared without BC and CA addition. After 7, 15, and 60 days of incubation with 60% (w/v) moisture level at 25 °C, the incubated soils were determined for pH and EC and were sequentially extracted to assess the metals' transformation in soil. The electronegative charges and XRD peaks of BC and BC-amended soils were also measured. Compared to CK, the application of BC, low level of CA (2 mM kg-1 soil) (CA2), and BC plus the low concentration of CA (BC-CA2) considerably declined the acid-soluble Cd, Pb, and Zn in which BC-CA2 was found to be the most effective treatment. The reversed trends were observed concerning the high levels of CA (>5-20 mM kg-1 soil) and the BC plus high concentrations of CA treatments. BC-CA2 changed the highest amounts of acid-soluble and reducible metals to the oxidizable and residual forms with time. The most increased electronegative charges of BC-CA2 indicate its (BC-CA2) highest Cd, Pb, and Zn immobilizing efficiency, probably through metals adsorption and fixation with the negative charge sites. The XRD study revealed the presence of P, O, CO32-, and Cl1- in BC, which might be responsible for the precipitation of CdCO3, pyromorphite, and hopeite in the case of Cd, Pb, and Zn immobilization, respectively. The findings depicted that the low concentration of CA increased metals' stabilization, whereas the high levels of CA enhanced their mobilization. The BC-CA2 emerged as the best amendment among treatments for metals stabilization in contaminated soils.

Keywords: Biochar, citric acid, immobilization, trace elements contaminated soil

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Authors: Yong Zhang

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Light has proven to be useful in a wide range of biomedical applications such as fluorescence imaging, photoacoustic imaging, optogenetics, photodynamic therapy, photothermal therapy, and light controlled drug/gene delivery. Taking photodynamic therapy (PDT) as an example, PDT has been proven clinically effective in early lung cancer, bladder cancer, head, and neck cancer and is the primary treatment for skin cancer as well. However, clinical use of PDT is severely constrained by the low penetration depth of visible light through thick tissue, limiting its use to target regions only a few millimeters deep. One way to enhance the range is to use invisible near-infrared (NIR) light within the optical window (700–1100nm) for biological tissues, extending the depth up to 1cm with no observable damage to the intervening tissue. We have demonstrated use of NIR-to-visible upconversion fluorescent nanoparticles (UCNPs), emitting visible fluorescence when excited by a NIR light at 980nm, as a nanotransducer for PDT to convert deep tissue-penetrating NIR light to visible light suitable for activating photosensitizers. The unique optical properties of UCNPs enable the upconversion wavelength to be tuned and matched to the activation absorption wavelength of the photosensitizer. At depths beyond 1cm, however, tissue remains inaccessible to light even within the NIR window, and this critical depth limitation renders existing phototherapy ineffective against most deep-seated cancers. We have demonstrated some new treatment modalities for deep-seated cancers based on UCNP hydrogel implants and miniaturized, wirelessly powered optoelectronic devices for light delivery to deep tissues.

Keywords: upconversion, fluorescent, nanoparticle, bioimaging, photodynamic therapy

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Authors: Emil F. Khisamutdinov

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Development of functional materials undergoing structural transformations in response to an external stimulus such as environmental changes (pH, temperature, etc.), the presence of particular proteins, or short oligonucleotides are of great interest for a variety of applications ranging from medicine to electronics. The dynamic operations of most nucleic acid (NA) devices, including circuits, nano-machines, and biosensors, rely on networks of NA strand displacement processes in which an external or stimulus strand displaces a target strand from a DNA or RNA duplex. The rate of strand displacement can be greatly increased by the use of “toeholds,” single-stranded regions of the target complex to which the invading strand can bind to initiate the reaction, forming additional base pairs that provide a thermodynamic driving force for transformation. Herein, we developed a highly robust nanoparticle shape transition, sequentially transforming DNA polygons from one shape to another using the toehold-mediated DNA strand displacement technique. The shape transformation was confirmed by agarose gel electrophoresis and atomic force microscopy. Furthermore, we demonstrate that our approach is applicable for RNA shape transformation from triangle to square, which can be detected by fluorescence emission from malachite green binding RNA aptamer. Using gel-shift and fluorescence assays, we demonstrated efficient transformation occurs at isothermal conditions (37°C) that can be implemented within living cells as reporter molecules. This work is intended to provide a simple, cost-effective, and straightforward model for the development of biosensors and regulatory devices in nucleic acid nanotechnology.

Keywords: RNA nanotechnology, bionanotechnology, toehold mediated DNA switch, RNA split fluorogenic aptamers

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Authors: Banu Hatice Gürcüm, Pınar Arslan, Mahmut Yalçın

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From the oldest production methods with yarns used to weave, knit, braid and knot to the newest production methods with fibres used to stitch, bond or structures of innovative technologies, laminates, nanoparticles, composites or 3D printing systems, textile industry advanced through materials, processes and context mostly within the last five decades. The creative momentum of fabric like 3D printed structures have come to the point of transforming as for the newest form of textile applications. Moreover, pioneering studies on the applications of 3D Printing Technology and Additive Manufacturing have been focusing on fashion and apparel sector from the last two decades beginning with fashion designers. After the advent of chain-mail like structures and flexible micro or meso structures created by SLS rapid manufacturing a more textile-like behavior is achieved. Thus, the primary aim of this paper is to discuss the most important properties of traditional fabrics that are to be expected of future fabrics. For this reason, this study deals primarily with the physical properties like softness, hand, flexibility, drapability and wearability of 3D Printed structures necessary to identify the possible ways in which it can be used instead of contemporary textile structures, namely knitted and woven fabrics. The aim of this study is to compare the physical properties of 3D printed fabrics regarding different rapid manufacturing methods (FDM and SLS). The implemented method was Material Driven Design (MDD), which comprise the use of innovative materials according to the production techniques such as 3D printing system. As a result, advanced textile processes and materials enable to the creation of new types of fabric structures and rapid solutions in the field of textiles and 3D fabrics on the other hand, are to be used in this regard.

Keywords: 3D printing technology, FDM, SLS, textile structure

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Authors: Samaneh Farokhirad, Fatemeh Ahmadpoor

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Biological membranes are constantly in contact with various filamentous soft nanostructures that either reside on their surface or are being transported between the cell and its environment. In particular, viral infections are determined by the interaction of viruses (such as filovirus) with cell membranes, membrane protein organization (such as cytoskeletal proteins and actin filament bundles) has been proposed to influence the mechanical properties of lipid membranes, and the adhesion of filamentous nanoparticles influence their delivery yield into target cells or tissues. The goal of this research is to integrate the rapidly increasing but still fragmented experimental observations on the adhesion and self-assembly of nanofilaments (including filoviruses, actin filaments, as well as natural and synthetic nanofilaments) on cell membranes into a general, rigorous, and unified knowledge framework. The global outbreak of the coronavirus disease in 2020, which has persisted for over three years, highlights the crucial role that nanofilamentbased delivery systems play in human health. This work will unravel the role of a unique property of all cell membranes, namely flexoelectricity, and the significance of nanofilaments’ flexibility in the adhesion and self-assembly of nanofilaments on cell membranes. This will be achieved utilizing a set of continuum mechanics, statistical mechanics, and molecular dynamics and Monte Carlo simulations. The findings will help address the societal needs to understand biophysical principles that govern the attachment of filoviruses and flexible nanofilaments onto the living cells and provide guidance on the development of nanofilament-based vaccines for a range of diseases, including infectious diseases and cancer.

Keywords: virus nanofilaments, cell mechanics, computational biophysics, statistical mechanics

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Authors: Christine A. Odinga, G. Sanjay, M. Mathew, S. Gupta, F. M. Swalaha, F. A. O. Otieno, F. Bux

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Wastewater discharged from municipal treatment plants contain an amalgamation of trace metals. The presence of metal pollutants in wastewater poses a huge challenge to the choice and applications of the preferred treatment method. Conventional treatment methods are inefficient in the removal of trace metals due to their design approach. This study evaluated the treatment performance of a constructed rhizofiltration system in the removal of heavy metals from municipal wastewater. The study was conducted at an eThekwni municipal wastewater treatment plant in Kingsburgh - Durban in the province of KwaZulu-Natal. The construction details of the pilot-scale rhizofiltration unit included three different layers of substrate consisting of medium stones, coarse gravel and fine sand. The system had one section planted with Phragmites australis L. and Kyllinga nemoralis L. while the other section was unplanted and acted as the control. Influent, effluent and sediment from the system were sampled and assessed for the presence of and removal of selected trace heavy metals using standard methods. Efficiency of metals removal was established by gauging the transfer of metals into leaves, roots and stem of the plants by calculations based on standard statistical packages. The Langmuir model was used to assess the heavy metal adsorption mechanisms of the plants. Heavy metals were accumulated in the entire rhizofiltration system at varying percentages of 96.69% on planted and 48.98% on control side for cadmium. Chromium was 81% and 24%, Copper was 23.4% and 1.1%, Nickel was 72% and 46.5, Lead was 63% and 31%, while Zinc was 76% and 84% on the on the water and sediment of the planted and control sides of the rhizofilter respectively. The decrease in metal adsorption efficiencies on the planted side followed the pattern of Cd>Cr>Zn>Ni>Pb>Cu and Ni>Cd>Pb>Cr>Cu>Zn on the control side. Confirmatory analysis using Electron Scanning Microscopy revealed that higher amounts of metals was deposited in the root system with values ranging from 0.015mg/kg (Cr), 0.250 (Cu), 0.030 (Pb) for P. australis, and 0.055mg/kg (Cr), 0.470mg/kg (Cu) and 0.210mg/kg,(Pb) for K. nemoralis respectively. The system was found to be efficient in removing and reducing metals from wastewater and further research is necessary to establish the immediate mechanisms that the plants display in order to achieve these reductions.

Keywords: wastewater treatment, Phragmites australis L., Kyllinga nemoralis L., heavy metals, pathogens, rhizofiltration

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Authors: Ayat Adnan Atwah, Muhammad A. Khan

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Self-cleaning surfaces are getting significant attention in industrial fields. Especially for textile fabrics, it is observed that self-cleaning textile fabric surfaces are created by manipulating the surface features with the help of coatings and nanoparticles, which are considered costly and far more complicated. However, controlling the fabrication parameters of textile fabrics at the microscopic level by exploring the potential for self-cleaning has not been addressed. This study aimed to establish the context of self-cleaning textile fabrics by controlling the fabrication parameters of the textile fabric at the microscopic level. Therefore, 3D-printed textile fabrics were fabricated using the low-cost fused filament fabrication (FFF) technique. The printing parameters, such as orientation angle (O), layer height (LH), and extruder width (EW), were used to control the microscopic features of the printed fabrics. The combination of three printing parameters was created to provide the best self-cleaning textile fabric surface: (LH) (0.15, 0.13, 0.10 mm) and (EW) (0.5, 0.4, 0.3 mm) along with two different (O) of (45º and 90º). Three different thermoplastic flexible filament materials were used: (TPU 98A), (TPE felaflex), and (TPC flex45). The printing parameters were optimised to get the optimum self-cleaning ability of the printed specimens. Furthermore, the impact of these characteristics on mechanical strength at the fabric-woven structure level was investigated. The study revealed that the printing parameters significantly affect the self-cleaning properties after adjusting the selected combination of layer height, extruder width, and printing orientation. A linear regression model was effectively developed to demonstrate the association between 3D printing parameters (layer height, extruder width, and orientation). According to the experimental results, (TPE felaflex) has a better self-cleaning ability than the other two materials.

Keywords: 3D printing, self-cleaning fabric, microscopic features, printing parameters, fabrication

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Authors: Selam M. Tefera

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Soil constitutes a crucial component of rural and urban environments. This fact is making role of heavy and trace elements in the soil system an issue of global concern. Heavy metals constitute an ill-defined group of inorganic chemical hazards, whose main source is anthropogenic activities mainly related to fabrications. This accumulation of heavy metals soils can prove toxic to the environment. The application of biochar to soil is one way of immobilizing these contaminants through sorption by exploiting the high surface area of this material among its other essential properties. This research examined the ability of sugar cane straw, an organic waste material from sugar farm, derived biochar and ash to remediate soil contaminated with heavy metals mainly Chromium and Zinc from the effluent of electroplating industry. Biochar was produced by varying the temperature from 300 °C to 500 °C and ash at 700 °C. The highest yield (50%) was obtained at the lowest temperature (300 °C). The proximate analysis showed ash content of 42.8%, ultimate analysis with carbon content of 67.18%, the Hydrogen to Carbon ratio of 0.54 and the results from FTIR analysis disclosed the organic nature of biochar. Methylene blue absorption indicated its fine surface area and pore structure, which increases with severity of temperature. Biochar was mixed with soil with at a ration varying from 4% w/w to 10% w/w of soil, and the response variables were determined at a time interval of 150 days, 180 days, and 210 days. As for ash (10% w/w), the characterization was performed at incubation time of 210 days. The results of pH indicated that biochar (9.24) had a notable liming capacity of acidic soil (4.8) by increasing it to 6.89 whereas ash increased it to 7.5. The immobilization capacity of biochar was found to effected mostly by the highest production temperature (500 °C), which was 75.5% for chromium and 80.5% for nickel. In addition, ash was shown to possess an outstanding immobilization capacity of 95.5% and 90.5% for Chromium and Nickel, respectively. All in all, the results from these methods showed that biochar produced from this specific biomass possesses the typical functional groups that enable it to store carbon, the appropriate pH that could remediate acidic soil, a fine amount of macro and micro nutrients that would aid plant growth.

Keywords: biochar, biomass, heavy metal immobalization, soil remediation

Procedia PDF Downloads 127

Authors: Yagahira E. Castro-Sesquen, Robert H. Gilman, Carolina Mejia, Daniel E. Clark, Jeong Choi, Melissa J. Reimer-Mcatee, Rocio Castro, Jorge Flores, Edward Valencia-Ayala, Faustino Torrico, Ricardo Castillo-Neyra, Lance Liotta, Caryn Bern, Alessandra Luchini

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Early diagnosis of reactivation of Chagas disease in HIV patients could be lifesaving; however, in Latin American the diagnosis is performed by detection of parasitemia by microscopy which lacks sensitivity. To evaluate if levels of T. cruzi antigens in urine determined by Chunap (Chagas urine nanoparticle test) are correlated with parasitemia levels in T. cruzi/HIV co-infected patients. T. cruzi antigens in urine of HIV patients (N=55: 31 T. cruzi infected and 24 T. cruzi serology negative) were concentrated using hydrogel particles and quantified by Western Blot and a calibration curve. The percentage of Chagas positive patients determined by Chunap compared to blood microscopy, qPCR, and ELISA was 100% (6/6), 95% (18/19) and 74% (23/31), respectively. Chunap specificity was 91.7%. Linear regression analysis demonstrated a direct relationship between parasitemia levels (determined by qPCR) and urine T. cruzi antigen concentrations (p<0.001). A cut-off of > 105 pg was chosen to determine patients with reactivation of Chagas disease (6/6). Urine antigen concentration was significantly higher among patients with CD4+ lymphocyte counts below 200/mL (p=0.045). Chunap shows potential for early detection of reactivation and with appropriate adaptation can be used for monitoring Chagas disease status in T. cruzi/HIV co-infected patients.

Keywords: antigenuria, Chagas disease, Chunap, nanoparticles, parasitemia, poly N-isopropylacrylamide (NIPAm)/trypan blue particles (polyNIPAm/TB), reactivation of Chagas disease.

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Authors: Md. Shoffikul Islam, Hongqing Hu

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Immobilizing trace elements by reducing their mobility and bioavailability through amendment application, especially biochar (BC), is a cost-effective and efficient method to address their toxicity in the soil environment. However, the low molecular weight organic acids (LMWOAs) in the rhizosphere could affect BC's efficiency to immobilize trace metals as the LMWOAs could either mobilize or fix metals in the soils. Therefore, understanding the BC's and LMWOAs' interaction mechanisms on metals stabilization in the rhizosphere is crucial. The present study examined the impact of BC derived from rice husk, tartaric acid (TA), and oxalic acid (OA), and the combination of BC and TA/OA on the changes of cadmium (Cd), lead (Pb), and zinc (Zn) among their geochemical forms through incubation experiment. The changes of zeta potential and X-ray diffraction (XRD) pattern of BC and BC-amended soils to investigate the probable mechanisms of trace elements' immobilization by BC under the attacks of TA and OA were also examined. The rice husk BC at 5% (w/w) was mixed with the air-dry soil (an Anthrosols) contaminated with Cd, Pb, and Zn in the plastic pot. The TA and OA each at 2, 5, 10, and 20 mM kg-1 (w/v) were added separately into the pot. All the ingredients were mixed thoroughly with the soil. A control (CK) treatment was also prepared without BC, TA, and OA addition. After 7, 15, and 60 days of incubation with 60% (w/v) moisture level at 25 °C, the incubated soils were determined for pH and EC and were sequentially extracted to assess the metals' transformation in soil. The electronegative charges and XRD peaks of BC and BC-amended soils were also measured. The BC, low level of TA (2 mM kg-1 soil), and BC plus the low concentration of TA (BC-TA2) addition considerably declined the acid-soluble Cd, Pb, and Zn in which BC-TA2 was found to be the most effective treatment. The trends were reversed concerning the high levels of TA (>5-20 mM kg-1 soil), all levels of OA (2-20 mM kg-1 soil), and the BC plus high levels of TA/OA treatments. BC-TA2 changed the highest amounts of acid-soluble and reducible metals to the oxidizable and residual fractions with time. The most increased electronegative charges of BC-TA2 indicate its (BC-TA2) highest metals' immobilizing efficiency, probably through metals adsorption and fixation with the negative charge sites. The XRD study revealed the presence of P, O, CO32-, and Cl1- in BC, which might be responsible for the precipitation of CdCO3, pyromorphite, and hopeite concerning Cd, Pb, and Zn immobilization, respectively. The findings demonstrated that the low level of TA increased metals immobilization, while the high levels of TA and all levels of OA enhanced their mobilization. The BC-TA2 was the best treatment in stabilizing metals in soil.

Keywords: biochar, immobilization, low molecular weight organic acids, trace elements contaminated soil

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Authors: S. Ghosh, L. Ramos, A. N. Kouamé, A.-L. Teillout, H. Remita

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Catalytic materials have attracted continuous attention due to their promising applications in a variety of energy and environmental applications including clean energy, energy conversion and storage, purification and separation, degradation of pollutants and electrochemical reactions etc. With the advanced synthetic technologies, polymer nanostructures and nanocomposites can be directly synthesized through soft template mediated approach using swollen hexagonal mesophases and modulate the size, morphology, and structure of polymer nanostructures. As an alternative to conventional catalytic materials, one-dimensional PDPB polymer nanostructures shows high photocatalytic activity under visible light for the degradation of pollutants. These photocatalysts are very stable with cycling. Transmission electron microscopy (TEM), and AFM-IR characterizations reveal that the morphology and structure of the polymer nanostructures do not change after photocatalysis. These stable and cheap polymer nanofibers and metal polymer nanocomposites are easy to process and can be reused without appreciable loss of activity. The polymer nanocomposites formed via one pot chemical redox reaction with 3.4 nm Pd nanoparticles on poly(diphenylbutadiyne) (PDPB) nanofibers (30 nm). The reduction of Pd (II) ions is accompanied by oxidative polymerization leading to composites materials. Hybrid Pd/PDPB nanocomposites used as electrode materials for the electrocatalytic oxidation of ethanol without using support of proton exchange Nafion membrane. Hence, these conducting polymer nanofibers and nanocomposites offer the perspective of developing a new generation of efficient photocatalysts for environmental protection and in electrocatalysis for fuel cell applications.

Keywords: conducting polymer, swollen hexagonal mesophases, solar photocatalysis, electrocatalysis, water depollution

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Authors: Anne Mastamet-Mason

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Crimes against women is a global concern, and South Africa, in particular, is in a dilemma of dealing with constant criminal acts that face the country. Debates on violence against women in South Africa cannot be overemphasised any longer as crimes continue to rise year by year. The recent death of a university student at the University of Cape Town, as well as many other cases, continues to strengthen the need to find solutions from all the spheres of South African society. The advanced textiles market contains a high number and variety of technologies, many of which have protected status and constitute a relatively small portion of the textiles used for the consumer market. Examples of advanced textiles include nanomaterials, such as silver, titanium dioxide and zinc oxide, designed to create an anti-microbial and self-cleaning layer on top of the fibers, thereby reducing body smell and soiling. Smart textiles propose materials and fabrics versatile and adaptive to different situations and functions. Integrating textiles and computing technologies offer an opportunity to come up with differentiated characteristics and functionality. This paper presents a proposal to design a smart camisole/Yoga sports brazier and a smart Yoga sports pant garment to be worn by women while alone and while in purported danger zones. The smart garments are to be worn under normal clothing and cannot be detected or seen, or suspected by perpetrators. The garments are imbued with devices to sense any physical aggression and any abnormal or accelerated heartbeat that may be exhibited by the victim of violence. The signals created during the attack can be transmitted to the police and family members who own a mobile application system that accepts signals emitted. The signals direct the receiver to the exact location of the offence, and the victim can be rescued before major violations are committed. The design of the Yoga sports garments will be done by Professor Mason, who is a fashion designer by profession, while the mobile phone application system will be developed by Mr. Amos Yegon, who is an independent software developer.

Keywords: smart clothing, wearable technology, south africa, 4th industrial revolution

Procedia PDF Downloads 176

Authors: Devendra Sillu, Shekhar Agnihotri

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The 'nano-biocatalyst' utilizes an ordered assembling of enzyme on to nanomaterial carriers to catalyze desirable biochemical kinetics and substrate selectivity. The current study describes an inter-disciplinary approach for converting agriculture waste, sugarcane bagasse into D-glucose exploiting halloysite nanotubes (HNTs) decorated cellulase enzyme as nano-biocatalytic system. Cellulase was successfully immobilized on HNTs employing polydopamine as an eco-friendly crosslinker while iron oxide nanoparticles were attached to facilitate magnetic recovery of material. The characterization studies (UV-Vis, TEM, SEM, and XRD) displayed the characteristic features of both cellulase and magnetic HNTs in the resulting nanocomposite. Various factors (i.e., working pH, temp., crosslinker conc., enzyme conc.) which may influence the activity of biocatalytic system were investigated. The experimental design was performed using Response Surface Methodology (RSM) for process optimization. Analyses data demonstrated that the nanobiocatalysts retained 80.30% activity even at elevated temperature (55°C) and excellent storage stabilities after 10 days. The repeated usage of system revealed a remarkable consistent relative activity over several cycles. The immobilized cellulase was employed to decompose agro-waste and the maximum decomposition rate of 67.2 % was achieved. Conclusively, magnetic HNTs can serve as a potential support for enzyme immobilization with long term usage, good efficacy, reusability and easy recovery from solution.

Keywords: halloysite nanotubes, enzyme immobilization, cellulase, response surface methodology, magnetic recovery

Procedia PDF Downloads 115

Authors: Sangwoo Oh, Jaewoo Kim, Dongmin Seo, Jaewon Park, Yongha Hwang, Sungkyu Seo

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Plasmonics has been regarded one of the most powerful bio-sensing modalities to evaluate bio-molecular interactions in real-time. However, most of the plasmonic sensing methods are based on labeling metallic nanoparticles, e.g. gold or silver, as optical modulation markers, which are non-recyclable and expensive. This plasmonic modulation can be usually achieved through various nano structures, e.g., nano-hole arrays. Among those structures, plasmonic lens has been regarded as a unique plasmonic structure due to its light focusing characteristics. In this study, we introduce a custom designed plasmonic lens array for bio-sensing, which was simulated by finite-difference-time-domain (FDTD) approach and fabricated by top-down approach. In our work, we performed the FDTD simulations of various plasmonic lens designs for bacteria sensor, i.e., Samonella and Hominis. We optimized the design parameters, i.e., radius, shape, and material, of the plasmonic lens. The simulation results showed the change in the peak intensity value with the introduction of each bacteria and antigen i.e., peak intensity 1.8711 a.u. with the introduction of antibody layer of thickness of 15nm. For Salmonella, the peak intensity changed from 1.8711 a.u. to 2.3654 a.u. and for Hominis, the peak intensity changed from 1.8711 a.u. to 3.2355 a.u. This significant shift in the intensity due to the interaction between bacteria and antigen showed a promising sensing capability of the plasmonic lens. With the batch processing and bulk production of this nano scale design, the cost of biological sensing can be significantly reduced, holding great promise in the fields of clinical diagnostics and bio-defense.

Keywords: plasmonic lens, FDTD, fabrication, bacteria sensor, salmonella, hominis

Procedia PDF Downloads 253

Authors: Rajani Kant Rai, Jayakrishnan Athipet

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There have been several attempts to prepare polymers with antimicrobial properties by doping with various N-halamines. Hydantoins (Cyclic N-halamine) is of importance due to their stability rechargeable chloroamide function, broad-spectrum anti-microbial action and ability to prevent resistance to the organisms. Polymerizable hydantoins are synthesized by tethering vinyl moieties to 5,5,-dialkyl hydantoin sacrificing the imide hydrogen in the molecule thereby restricting the halogen capture only to the amide nitrogen that results in compromised antibacterial activity. In order to increase the activity of the antimicrobial polymer, we have developed a scheme to maximize the attachment of chlorine to the amide and the imide moieties of hydantoin. Vinyl hydantoin monomer, (Z)-5-(4-((3-methylbuta-1,3-dien-2-yl)oxy)benzylidene)imidazolidine-2,4-dione (MBBID) was synthesized and copolymerized with a commercially available monomer, methyl methacrylate, by free radical polymerization. The antimicrobial activity of hydantoin is strongly dependent on their surface area and hence their microbial activity increases when incorporated in microspheres or nanoparticles as compared to their bulk counterpart. In this regard, smooth and rough surface microsphere of the vinyl monomer (MBBID) with commercial monomer was synthesized. The oxidative chlorine content of the copolymer ranged from 1.5 to 2.45 %. Further, to demonstrate the water purification potential, the thin column was packed with smooth or rough microspheres and challenged with simulated contaminated water that exhibited 6 log kill (total kill) of the bacteria in 20 minutes of exposure with smooth (25 mg/ml) and rough microsphere (15.0 mg/ml).

Keywords: cyclic N-halamine, vinyl hydantoin monomer, rough surface microsphere, simulated contaminated water

Procedia PDF Downloads 129