Search results for: Cochlear implants

Authors: D. Zujur, J. Moret, D. Rodriguez, L. Cruz, J. Lira, L. Gil, E. Dominguez, J. F. Alvarez-Barreto

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In this work, chitosan (CH) has been used to produce a novel coating for Ti6Al4V, the most widely used alloy in orthopedic implants, so as to improve the biological tissue response at the metallic surface. The Ti6Al4V surface was sandblasted with alumina particles and observed by SEM. Chitosan was chemically modified, via crodiimide chemistry, with lactobionic and 4-azidebenzoic acid to make it soluble at physiological pH and photo-crosslinkable, respectively. The reaction was verified by FTIR, NMR, and UV/vis spectroscopy. Ti6Al4V surfaces were coated with solutions of the modified CH and exposed to UV light, causing the polymer crosslinking, and formation of a hydrogel on the surface. The crosslinking reaction was monitored by FTIR at different exposure times. Coating morphology was observed by SEM. The coating´s cytocompatibility was determined in vitro through the culture of rat bone marrow´s mesenchymal stem cells, using an MTT assay. The results show that the developed coating is cytocompatible, easy to apply and could be used for further studies in the encapsulation of bioactive molecules to improve osteogenic potential at the tissue-implant interface.

Keywords: chitosan, photo-crosslinking, Ti6Al4V, bioactive coating, hydrogel

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Authors: Virgil Florescu, Lucian Capitanu

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The studies performed by the author and presented here focus mainly on the FE simulation of some relevant phenomena related to stability of orthopedic implants, especially those components of Total Hip Prostheses. The objectives are to study the mechanisms of achieving stability of acetabular prosthetic components and the influence of some characteristic parameters, to evaluate the effect of femoral stem fixation modality on the stability of prosthetic component and to predict long-term behavior, to analyze a critical phenomena which influence the loading transfer mechanism through artificial joints and could lead to aseptic loosening – the wear of joint frictional surfaces. After a theoretical background an application is made considering only three activities: normal walking, stair ascending and stair descending. For each activity, this function is maximized in a different locations: if for normal walking the maxima is in the superior-posterior part of the acetabular cup, for stair descending this maxim value could be located rather in the superior-anterior part, for stair ascending being even closer to the central area of the cup.

Keywords: THA, acetabular stability, FEM simulation, stresses and displacements, wear tests, wear simulation

Procedia PDF Downloads 240

Authors: M. Kagan Keler, Sibel Daglilar, Isil Kerti, Oguzhan Gunduz

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Electrospinning is a versatile way to occur fibers at nano-scale and polycaprolactone is a biomedical material which has a wide usage in cartilage defects and tissue regeneration. PCL is biocompatible and durable material which can be used in bio-implants. Therefore, electrospinning process was chosen as a fabrication method to get PCL fibers in an effective way because of its significant adjustments. In this research study, electrospinning parameters was evaluated during the producing of polymer tissue scaffolds. Polycaprolactone’s molecular weight was 80.000 Da and was employed as a tissue material in the electrospinning process. PCL was decomposed in dimethylformamid(DMF) and chloroform(CF) with the weight ratio of 1:1. Different compositions (1%, 3%, 5%, 10% and 20 %) of PCL was prepared in the laboratory conditions. All solvents with different percentages of PCL have been taken into the syringe and loaded into the electrospinning system. In electrospinning dozens of trial were applied to get homogeneously uniform scaffold samples. Taylor cone which is crucial point for electrospinning characteristic was occurred and changed in different voltages up to the material compositions’ conductivity. While the PCL percentages were increasing in the electrospinning, structure started to arise with droplets, which was an expressive problem for tissue scaffold. The vertical and horizontal layouts were applied to produce non-woven structures at all.

Keywords: tissue engineering, artificial scaffold, electrospinning, biocomposites

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Authors: Farzana Majid, Mahwish Bashir, Ammara, Attia Falak

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Zirconia nanoparticles have gained significant attention due to their excellent mechanical strength, thermal properties, biocompatibility, and catalytic activity. Tetragonal zirconia holds the greatest efficacy for surgical implants and coatings when it comes to the three zirconia phases (monoclinic, tetragonal, and cubic). However, its stability at higher temperatures and transformation to the monoclinic phase upon cooling are challenging. In this research, zirconia nanoparticles were prepared using microwave-assisted sol-gel method with varying microwave powers (100 W, 300 W, 500 W, 700 W, & 900 W). Organic stabilizing agent, i.e., eggshell powder, was used to stabilize the tetragonal phase. Fourier transform infrared spectroscopy (FTIR) confirmed the phase-pure tetragonal zirconia, corroborating the XRD data. Optical properties, including the optical bandgap, were studied using UV/Visible and PL spectroscopies. The synthesized ZrO2 nanoparticles exhibited excellent photocatalytic degradation efficiency in the degradation of methylene blue (MB) dye under UV irradiation. The findings demonstrate the potential of these ZrO2 nanoparticles as a viable alternative photocatalyst for the efficient degradation of various dyes in contaminated water.

Keywords: zirconia nanoparticles, sol-gel, photocataylsis, wter purification

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Authors: Adil Elrayah, Jie Weng, Esra Suliman

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The mineral in human bone is not pure stoichiometric calcium phosphate (Ca/P) as it is partially substituted by in organic elements. In this study, the copper ions (Cu²⁺) substituted hydroxyapatite (CuHA) powder has been synthesized by the co-precipitation method. The CuHA powder has been used to fabricate CuHA fiber scaffolds by sol-gel process and the following sinter process. The resulted CuHA fibers have slightly different microstructure (i.e. porosity) compared to HA fiber scaffold, which is denser. The mechanical properties test was used to evaluate CuHA, and the results showed decreases in both compression strength and hardness tests. Moreover, the in vitro used endothelial cells to evaluate the angiogenesis of CuHA. The result illustrated that the viability of endothelial cell on CuHA fiber scaffold surfaces tends to antigenic behavior. The results obtained with CuHA scaffold give this material benefit in biological applications such as antimicrobial, antitumor, antigens, compacts, filling cavities of the tooth and for the deposition of metal implants anti-tumor, anti-cancer, bone filler, and scaffold.

Keywords: fiber scaffold, copper ions, hydroxyapatite, in vitro, mechanical property

Procedia PDF Downloads 129

Authors: R. V. Dahibhate, A. B. Deoghare, P. M. Padole

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Maintaining natural integrity of biosystem is paramount significant for orthopedic surgeon while performing surgery. Restoration is challenging task to rehabilitate trauma patient. Drilling is an inevitable procedure to fix implants. The task leads to rise in temperature at the contact site which intends to thermal necrosis. A precise monitoring can avoid thermal necrosis. To accomplish it, data acquiring instrument is integrated with the drill bit. To contemplate it, electronic feedback system is developed. It not only measures temperature without any physical contact in between measuring device and target but also visualizes the site and monitors correct movement of tool path. In the current research work an infrared thermometer data acquisition system is used which monitors variation in temperature at the drilling site and a camera captured movement of drill bit advancement. The result is presented in graphical form which represents variations in temperature, drill rotation and time. A feedback system helps in keeping drill speed in threshold limit.

Keywords: thermal necrosis, infrared thermometer, drilling tool, feedback system

Procedia PDF Downloads 206

Authors: Neelesh Papineni

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Aim: Piezosurgery is a relatively new technique for osteotomy and osteoplasty that uses ultrasonic vibration. The conventional method of treating periodontal cases are by conventional surgeries. However, in this advancing field the use of motor-driven instruments is being considered less invasive. Out of these motor-driven instruments, piezo-electric device has been introduced to the field of periodontics and oral implantology. This article discusses about the wide range of application of piezo-electric device in periodontology, its advantages over conventional surgical therapies and other motor-driven instruments. Results: Piezo- electric has shown better results in aspect of osteotomy, osteoplasty, implants, and any procedure which includes conserving the bone. Also piezo-electric does not cause any kind of damage to the surrounding soft tissue and eliminates the risk of bone necrosis which is a risk factor in other motor driven instruments. Conclusion: In this era of modern dentistry , a successful periodontal and implant surgery requires a sound osseous support. This review gives a pictorial representation about the wide range of application of piezo-electric device in periodontology.

Keywords: piezo-electric, osteotomy, osteoplasty, implantology

Procedia PDF Downloads 336

Authors: Khaja Moiduddin, Sherif Mohammed Elseufy, Hisham Alkhalefah

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Recent advances in three-dimensional (3D) printing, medical imaging, and implant design may alter how craniomaxillofacial surgeons construct individualized treatments using patient data. By utilizing medical image data, medical professionals can obtain detailed information about a patient's injuries, enabling them to conduct a thorough preoperative assessment while ensuring the implant's accuracy. However, selecting the right implant material requires careful consideration of various mechanical properties. This study aims to compare the two commonly used implant material for cranial reconstruction which includes titanium (Ti6Al4V) and Polyetheretherketone (PEEK). Biomechanical analysis was performed to study the implant behavior, by keeping the implant design and fixation constant in both cases. A finite element model was created and analyzed under loading conditions. The finite element analysis proves that although Ti6Al4V is stronger than PEEK but, its mechanical strength is adequate to bear the loads of the adjacent bone tissue.

Keywords: cranial reconstruction, titanium implants, PEEK, finite element model

Procedia PDF Downloads 44

Authors: William Huang

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Retinal prostheses are currently limited to low resolution grayscale images that lack color and spatial information. This study develops a novel real-time image optimization framework and tools to encode maximum information to the prostheses which are constrained by the number of electrodes. One key idea is to localize main objects in images while reducing unnecessary background noise through region-contrast saliency maps. A novel color depth mapping technique was developed through MiniBatchKmeans clustering and color space selection. The resulting image was downsampled using bicubic interpolation to reduce image size while preserving color quality. In comparison to current schemes, the proposed framework demonstrated better visual quality in tested images. The use of the region-contrast saliency map showed improvements in efficacy up to 30%. Finally, the computational speed of this algorithm is less than 380 ms on tested cases, making real-time retinal prostheses feasible.

Keywords: retinal implants, virtual processing unit, computer vision, saliency maps, color quantization

Procedia PDF Downloads 116

Authors: J. Palán, M. Zemko

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COMTES FHT has been active in a field of research and development of high-strength wires for quite some time. The main material was pure titanium. The primary goal of this effort is to develop a continuous production process for ultrafine and nanostructured materials with the aid of severe plastic deformation (SPD). This article outlines mechanical and microstructural properties of the materials and the options available for testing the components made of these materials. Ti Grade 2 and Grade 4 wires are the key products of interest. Ti Grade 2 with ultrafine to nano-sized grain shows ultimate strength of up to 1050 MPa. Ti Grade 4 reaches ultimate strengths of up to 1250 MPa. These values are twice or three times as higher as those found in the unprocessed material. For those fields of medicine where implantable metallic materials are used, bulk ultrafine to nanostructured titanium is available. It is manufactured by SPD techniques. These processes leave the chemical properties of the initial material unchanged but markedly improve its final mechanical properties, in particular, the strength. Ultrafine to nanostructured titanium retains all the significant and, from the biological viewpoint, desirable properties that are important for its use in medicine, i.e. those properties which made pure titanium the preferred material also for dental implants.

Keywords: CONFORM, ECAP, rotary swaging, titanium

Procedia PDF Downloads 218

Authors: Awais Ali, Hesham Ali

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The absence of teeth through either premature loss or developmental absence is a common condition with potentially severe impact on affected individuals. Management of these cases presents a clinical challenge which may be difficult to resolve given the effects of tooth loss or hypodontia over the course of a patient’s lifetime. Treatment of such cases is often best provided by a multi-disciplinary team, where the patient’s expectations and care delivery can be optimally managed. Orthodontic treatment is often used to prepare the dentition in advance of restorative replacement of missing teeth. Conversely, the placement of implants may precede the delivery of orthodontic treatment and indeed may function as an adjunctive orthodontic procedure. We discuss the use of both approaches here and illustrate their clinical implementation with two case reports. The first case demonstrates the use of fixed appliances to prepare the mouth for an opposing implant-retained complete denture. A second case demonstrates the use of implant-retained crowns to provide orthodontic anchorage in a partially dentate patient. We propose that complex cases such as these should always be planned and treated by a multi-disciplinary team in order to optimise the delivery of care, patient experience, and treatment outcome. The presented cases add to the body of evidence in this area.

Keywords: orthodontics, dental implantology, hypodontia, multi-disciplinary

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Authors: M. Safiqul Islam, Md Arafat Hossain Sarkar

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Brachytherapy is one of the most important cancer treatment management systems in radiotherapy department. Brachytherapy treatment is moved into High Dose Rate (HDR) after loader from Low Dose Rate (LDR) after loader due to radiation protection advantage. HDR Brachytherapy is a highly multipurpose system for enhancing cure and achieving palliation in many common cancers disease of developing countries. High-dose rate (HDR) Brachytherapy is a type of internal radiation therapy that delivers radiation from implants placed close to or inside, the tumor(s) in the body. This procedure is very effective at providing localized radiation to the tumor site while minimizing the patient’s whole body dose. Brachytherapy has proven to be a highly successful treatment for cancers of the prostate, cervix, endometrium, breast, skin, bronchus, esophagus, and head and neck, as well as soft tissue sarcomas and several other types of cancer. For the time being in our country we have 10 new HDR Remote after loading Brachytherapy. Right now 4 HDR Brachytherapy is already installed and running for patient’s treatment out of 10 HDR Brachytherapy. Ir-192 source is more comfortable than Co-60. In that case people or expert personnel prefer Ir-192 source for different kind of cancer patients. Ir-192 are economically, more flexible and familiar in our country.

Keywords: Ir-192, brachytherapy, cancer treatment, prostate, cervix, endometrium, breast, skin, bronchus, esophagus, soft tissue sarcomas

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Authors: Mehmet Akoz, Mustafa Kul

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Ewes and goats are seasonally polyestrus animals. Their reproductive activities are associated with the reduction or extending of daylight. Melatonin releasing from pineal gland regulates the sexual activities depending on daylight. In recent years, number of ewes decreased in our country. This situation dispatched to developing of some methods to increase productivity. Small ruminants can be synchronized with the natural and medical methods. known methods from natural light set with ram and goat participation. The most important natural methods of male influence, daylight is regulated and feed. On the other hand, progestagens, PGF2α, melatonin, and gonadotropins are commonly used for the purpose of estrus synchranization. But it is not effective PGF2α anestrous season The short-term and long-term progesterone treatment was effective to synchronize estrus in small ruminats during both breeding and anestrus seasons. Alternative choices of progesterone/progestagen have been controlled internal drug release (CIDR) devices, supplying natural progesterone, norgestomet implants, and orally active melengestrol acetate Melatonin anestrous season and should be applied during the transition period, but the season can be synchronized. Estrus synchronisation shortens anestrus season, decreases labor for mating/insemination and estrus pursuit, and induces multiple pregnancies.

Keywords: ewes, goat, synchronization, progestagen, PGF2α

Procedia PDF Downloads 315

Authors: L. Siva Rama Krishna, Sriram Venkatesh, M. Sastish Kumar, M. Uma Maheswara Chary

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Rapid Prototyping (RP) is a technology that produces models and prototype parts from 3D CAD model data, CT/MRI scan data, and model data created from 3D object digitizing systems. There are several RP process like Stereolithography (SLA), Solid Ground Curing (SGC), Selective Laser Sintering (SLS), Fused Deposition Modelling (FDM), 3D Printing (3DP) among them SLS and FDM RP processes are used to fabricate pattern of custom cranial implant. RP technology is useful in engineering and biomedical application. This is helpful in engineering for product design, tooling and manufacture etc. RP biomedical applications are design and development of medical devices, instruments, prosthetics and implantation; it is also helpful in planning complex surgical operation. The traditional approach limits the full appreciation of various bony structure movements and therefore the custom implants produced are difficult to measure the anatomy of parts and analyse the changes in facial appearances accurately. Cranioplasty surgery is a surgical correction of a defect in cranial bone by implanting a metal or plastic replacement to restore the missing part. This paper aims to do a comparative study on the dimensional error of CAD and SLS RP Models for reconstruction of cranial defect by comparing the virtual CAD with the physical RP model of a cranial defect.

Keywords: rapid prototyping, selective laser sintering, cranial defect, dimensional error

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Authors: Sara Mercedes Barroso Pinzón, Álvaro Jesús Caicedo Castro, Antonio Javer Sánchez Herencia

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In recent years there has been increased academic and industrial research into the development of orthopaedic implants with structural properties and functionality similar to mechanical strength, osseointegration, thermal stability and antibacterial capacity similar to bone structure. Hydroxyapatite has been considered for decades as an ideal biomaterial for bone regeneration due to its chemical and crystallographic similarity to the mineral structure bioapatites. However, the lack of trace elements in the hydroxyapatite structure confers very low mechanical and biological properties. Under this scenario, the objective of the research is the synthesis of hydroxyapatite with Mg from the francolite mineral present in phosphate rock from the central-eastern region of Colombia, taking advantage of the extraction of mineral species as natural precursors of Ca, P and Mg. The minerals present were studied, fluorapatite as the mineral of interest associated with magnesium carbonates and quartz. The chemical and mineralogical composition was determined by X-ray fluorescence (XRF) and X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX); the optimum conditions were established using the acid leaching mechanism in the wet concentration process. From the products obtained and characterised by XRD, XRF, SEM, FTIR, RAMAN, HAp-Mg biocomposite scaffolds are fabricated and the influence of Mg on morphometric parameters, mechanical and biological properties in the formed materials is evaluated.

Keywords: phosphate rock, hydroxyapatite, magnesium, biomaterials

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Authors: Khurram Munir, Cuie Wen, Yuncang Li

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Magnesium (Mg) metal matrix composites (MMCs) reinforced with graphene nanoplatelets (GNPs) have been developed by powder metallurgy (PM). In this study, GNPs with different concentrations (0.1-0.3 wt.%) were dispersed into Mg powders by high-energy ball-milling processes. The microstructure and resultant mechanical properties of the fabricated nanocomposites were characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Raman spectroscopy (RS), compression and nano-wear tests. The corrosion resistance of the fabricated composites was evaluated by electrochemical tests and hydrogen evolution measurements. Finally, the biological response of Mg-GNPs composites was assessed using osteoblast-like SaOS2 cells. The results indicate that GNPs are excellent candidates as reinforcements in Mg matrices for the manufacture of biodegradable Mg-based composite implants. GNP addition improved the mechanical properties of Mg via synergetic strengthening modes. Moreover, retaining the structural integrity of GNPs during PM processing improved the ductility, compressive strength, and corrosion resistance of the Mg-GNP composites as compared to monolithic Mg. Cytotoxicity assessments did not reveal any significant toxicity with the addition of GNPs to Mg matrices. This study demonstrates that Mg-xGNPs with x < 0.3 wt.%, may constitute novel biodegradable implant materials for load-bearing applications.

Keywords: magnesium-graphene composites, strengthening mechanisms, In vitro cytotoxicity, biocorrosion

Procedia PDF Downloads 133

Authors: Daniel Francis, Mo Yassin

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Transverse patella fractures are routinely fixed using tension band wiring (TBW) using Kirschner wires and a wire in the shape of a figure of 8. The idea of the study was to compare the outcomes of the traditional technique against the more recently used cannulated screws and fiber tape in the shape of a figure of 8. We performed a retrospective cohort study of all the surgically fixed patella fractures from the year 2019 to 2022. The patients were divided into two groups TBW group and cannulated screws group. The primary outcome measure was the failure of fixation and the need for the removal of metalwork. Twenty-six patellar fractures were studied. TBW was used in 14 (53.8%), and cannulated screws were used for fixation in 12 (46.2%). There was one incident of metalwork failure in the TBW and one incident in the cannulated screws group. Five (35.7%) of patients in the TBW needed symptomatic metal work removed and One (8.3%) in the cannulated screw group. In both groups, the rate of fixation failure was low. Symptomatic implants, the most common complication observed, were higher in the TBW group in our practice. Although the small numbers in both groups, the hope of this study is to shine the light on the use of cannulated screws for patella fractures as it would reduce the need for a second operation and reduce the load on the already stretched services as well as improving the patient experience by not requiring further surgery. Although this is not a brand-new technique, it is not commonly used as there have not yet been any studies that demonstrate the lower rates of second surgery needed.

Keywords: patella, tension band wiring, randomised, new technique

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Authors: Amin Jabbari

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The state of the art in major 3D printing technologies, such as powder-based and slurry based, has led researchers to investigate the ability to fabricate bone scaffolds for bone tissue engineering using biomaterials. In addition, 3D printing technology can simulate mechanical and biological surface properties and print with high precision complex internal and external structures that match their functional properties. Polymer matrix composites reinforced with particulate bioceramics, hydrogels reinforced with particulate bioceramics, polymers coated with bioceramics, and non-porous bioceramics are among the materials that can be investigated for bone scaffold printing. Furthermore, it was shown that the introduction of high-density micropores into the sparingly dissolvable CSiMg10 and dissolvable CSiMg4 shell layer inevitably leads to a nearly 30% reduction in compressive strength, but such micropores can easily influence the ion release behavior of the scaffolds. Also, biocompatibility tests such as cytotoxicity, hemocompatibility and genotoxicity were tested on printed parts. The printed part was tested in vitro, and after 24-26 h for cytotoxicity, and 4h for hemocompatibility test, the CSiMg4@CSiMg10-p scaffolds were found to have significantly higher osteogenic capability than the other scaffolds of implantation. Overall, these experimental studies demonstrate that 3D printed, additively-manufactured bioceramic calcium (Ca)-silicate scaffolds with appropriate pore dimensions are promising to guide new bone ingrowth.

Keywords: AM, 3D printed implants, bioceramic, tissue engineering

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Authors: Amin Davoudi

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Aim: New approaches have been introduced to improve soft tissue indices of the dental implants. This systematic review aimed to investigate the effect of computer-aided design and computer-assisted manufacture (CAD/CAM) zirconia (Zr) implant abutments on periodontal aspects. Materials and Methods: Five electronic databases were searched thoroughly based on prior defined MeSH and non-MeSH keywords. Clinical studies were collected via hand searches in English language journals up to September 2020. Interproximal papilla stability, papilla recession, pink and white esthetic score (PES, WES), bone and gingival margin levels, color, and contour of soft tissue were reviewed. Results: The initial literature search yielded 412 articles. After the evaluation of abstracts and full texts, six studies were eligible to be screened. The study design of the included studies was a prospective cohort (n=3) and randomized clinical trial (n=3). The outcome was found to be significantly better for Zr than titanium abutments, however, the studies did not show significant differences between stock and CAD/CAM abutments. Conclusion: Papilla fill, WES, PES, and the distance from the contact point to dental crest bone of adjacent tooth and inter-tooth–implant distance were not significantly different between Zr CAD/CAM and Zr stock abutments. However, soft tissue stability and recession index were better in Zr CAD/CAM abutments.

Keywords: zirconia, CADCAM, periodental, implant

Procedia PDF Downloads 73

Authors: Whitehead-Clarke T., Beynon V., Banks J., Karanjia R., Mudera V., Windsor A., Kureshi A.

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Introduction: Mesh implants are regularly used to help repair both hiatus hernias (HH) and diaphragmatic hernias (DH). In vivo studies are used to test not only mesh safety but increasingly comparative efficacy. Our work examines the field of in vivo mesh testing for HH and DH models to establish current practices and standards. Method: This systematic review was registered with PROSPERO. Medline and Embase databases were searched for relevant in vivo studies. 44 articles were identified and underwent abstract review, where 22 were excluded. 4 further studies were excluded after full text review – leaving 18 to undergo data extraction. Results: Of 18 studies identified, 9 used an in vivo HH model and 9 a DH model. 5 studies undertook mechanical testing on tissue samples – all uniaxial in nature. Testing strip widths ranged from 1-20mm (median 3mm). Testing speeds varied from 1.5-60mm/minute. Upon histology, the most commonly assessed structural and cellular factors were neovascularization and macrophages, respectively (n=9 each). Structural analysis was mostly qualitative, where cellular analysis was equally likely to be quantitative. 11 studies assessed adhesion formation, of which 8 used one of four scoring systems. 8 studies measured mesh shrinkage. Discussion: In vivo studies assessing mesh for HH and DH repair are uncommon. Within this relatively young field, we encourage surgical and materials testing institutions to discuss its standardisation.

Keywords: hiatus, diaphragmatic, hernia, mesh, materials testing, in vivo

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Authors: Lela Pintarić, Iva Rezić, Ana Vrsalović Presečki

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Considering an enormous increase of the use of metal nanoparticles with the exactly defined characteristics, the main goal of this research was to found the optimal and environmental friendly method of their synthesis. The synthesis of the inorganic core-shell nanoparticles was optimized as a model. The core-shell nanoparticles are composed of the enzyme core belted with the metal ions, oxides or salts as a shell. In this research, enzyme urease was the core catalyst and the shell nanoparticle was made of silver. Silver nanoparticles are widespread utilized and some of their common uses are: as an addition to disinfectants to ensure an aseptic environment for the patients, as a surface coating for neurosurgical shunts and venous catheters, as an addition to implants, in production of socks for diabetics and athletic clothing where they improve antibacterial characteristics, etc. Characteristics of synthesized nanoparticles directly depend on of their size, so the special care during this optimization was given to the determination of the size of the synthesized nanoparticles. For the purpose of the above mentioned optimization, sixteen experiments were generated by the Design of Experiments (DoE) method and conducted under various temperatures, with different initial concentration of the silver nitrate and constant concentration of the urease of two separate manufacturers. Synthesized nanoparticles were analyzed by the Nanoparticle Tracking Analysis (NTA) method on Malvern NanoSight NS300. Results showed that the initial concentration of the silver ions does not affect the concentration of the synthesized silver nanoparticles neither their size distribution. On the other hand, temperature of the experiments has affected both of the mentioned values.

Keywords: core-shell nanoparticles, optimization, silver, urease

Procedia PDF Downloads 282

Authors: Monika Bansal

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Background: Placement of dental implant in narrow alveolar ridge is challenging to be treated. GBR procedure is currently most widely used to augment the deficient alveolar ridges and to treat the fenestration and dehiscence around dental implants. Thus, the objectives of the present study were to evaluate as well as compare the clinical performance of collagen membrane and titanium mesh for horizontal bone augmentation at dehisced implant sites. Methods and material: Total 12 single edentulous implant sites with buccal bone deficiency in 8 subjects were equally divided and treated simultaneously with either of the two membranes and DBBM(Bio-Oss) bone graft. Primary outcome measurements in terms of defect height and defect width were made using a calibrated plastic periodontal probe. Re-entry surgery was performed to remeasure the augmented site and to remove Ti-mesh at 6th month. Independent paired t-tests for the inter-group comparison and student-paired t-tests for the intra-group comparison were performed. The differences were considered to be significant at p ≤ 0.05. Results: Mean defect fill with respect to height and width was 3.50 ± 0.54 mm (87%) and 2.33 ± 0.51 mm (82%) for collagen membrane and 3.83 ± 0.75 mm (92%) and 2.50 ± 0.54 mm (88%) for Ti-mesh group respectively. Conclusions: Within the limitation of the study, it was concluded that mean defect height and width after 6 months were statistically significant within the group without significant difference between them, although defect resolution was better in Ti-mesh.

Keywords: collagen membrane, dehiscence, dental implant, horizontal bone, augmentation, ti-mesh

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Authors: Ardiansyah I. Ryan, Ashsholih K. R., Fathurrohman G. R., Kurniadi M. R., Huda P. A

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The burden of brain-related disease is very high. There are a lot of brain-related diseases with limited treatment result and thus raise the burden more. The Parkinson Disease (PD), Mental Health Problem, or Paralysis of extremities treatments had risen concern, as the patients for those diseases usually had a low quality of life and low chance to recover fully. There are also many other brain or related neural diseases with the similar condition, mainly the treatments for those conditions are still limited as our understanding of the brain function is insufficient. Brain Implant Technology had given hope to help in treating this condition. In this paper, we examine the current update of the brain implant technology. Neurotechnology is growing very rapidly worldwide. The United States Food and Drug Administration (FDA) has approved the use of Deep Brain Stimulation (DBS) as a brain implant in humans. As for neural implant both the cochlear implant and retinal implant are approved by FDA too. All of them had shown a promising result. DBS worked by stimulating a specific region in the brain with electricity. This device is planted surgically into a very specific region of the brain. This device consists of 3 main parts: Lead (thin wire inserted into the brain), neurostimulator (pacemaker-like device, planted surgically in the chest) and an external controller (to turn on/off the device by patient/programmer). FDA had approved DBS for the treatment of PD, Pain Management, Epilepsy and Obsessive Compulsive Disorder (OCD). The target treatment of DBS in PD is to reduce the tremor and dystonia symptoms. DBS has been showing the promising result in animal and limited human trial for other conditions such as Alzheimer, Mental Health Problem (Major Depression, Tourette Syndrome), etc. Every surgery has risks of complications, although in DBS the chance is very low. DBS itself had a very satisfying result as long as the subject criteria to be implanted this device based on indication and strictly selection. Other than DBS, there are several brain implant devices that still under development. It was included (not limited to) implant to treat paralysis (In Spinal Cord Injury/Amyotrophic Lateral Sclerosis), enhance brain memory, reduce obesity, treat mental health problem and treat epilepsy. The potential of neurotechnology is unlimited. When brain function and brain implant were fully developed, it may be one of the major breakthroughs in human history like when human find ‘fire’ for the first time. Support from every sector for further research is very needed to develop and unveil the true potential of this technology.

Keywords: brain implant, deep brain stimulation (DBS), deep brain stimulation, Parkinson

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Authors: Helen Nelly Naiga, Christopher Garimoi Orach

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Introduction: Long-acting reversible contraceptive (LARC) methods are highly effective. However, LARC use in Uganda is low (13%). We assessed the factors associated with the use of long-acting reversible contraceptives among women of reproductive age (15-49 yrs) in Jinja District. Methods: We conducted a facility-based cross-sectional study. A total of 314 women aged 15–49 years attending public health facilities (1 hospital and 3 health center IV) in Jinja district, were randomly selected. A total of 6 key informants and 6 in-depth interviews were conducted. Logistic regression analysis was conducted using Stata version 14. Qualitative data were analysed using thematic analysis. Results: The study found that 40.45% of the respondents had ever used LARC. The commonest LARC method used was implanting (38.22%). The factors significantly associated with use of LARC were employment (AOR =2.91; 95% CI (1.05-8.08), access to LARC methods (AOR =4.48; 95% CI (1.24-16.21), husband support (AOR =4.90; 95% CI (1.56-15.41), and experience of no side effects (AOR =3.48; 95% CI (1.00-12.19). Conclusion and recommendations: The study showed that 4 in 10 women of reproductive age in Jinja District were using LARC. The factors associated with LARC use were employment, husband support, access to LARC methods, and the lack of side effects. There is a need to strengthen client education, improve accessibility to LARC methods at all levels of health centers, improve male partner’s decision-making in LARC use and manage the side effects effectively.

Keywords: family planning, implants, intrauterine device, long-acting reversible contraceptives (LARC)

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Authors: V. E. Bazhenov, A. V. Li, A. A. Komissarov, A. V. Koltygin, S. A. Tavolzhanskii, O. O. Voropaeva, A. M. Mukhametshina, A. A. Tokar, V. A. Bautin

Abstract:

Magnesium-based alloys are considered as effective materials in the development of biodegradable implants. The magnesium alloys containing Mg, Zn, Ca as an alloying element are the subject of the particular interest. These elements are the nutrients for the human body, which provide their high biocompatibility. In this work, we investigated the effect of severe plastic deformation (SPD) on the mechanical and corrosion properties of Mg-Zn-Ca and Mg-Zn-Ca-Mn alloys containing from 2 to 4 wt.% Zn; 0.7 wt.% Ca and up to 1 wt.% Mn. Hot extrusion was used as a method of intensive plastic deformation. The temperature of hot extrusion was set to 220 °C and 300 °C. Metallographic analysis after hot extrusion shows that the grain size in the studied alloys depends on the deformation temperature. The grain size for all of investigated alloys is in the range from 3 to 7 microns, and 3 μm corresponds to the extrusion temperature of 220 °C. Analysis of mechanical properties after extrusion shows that extrusion at a temperature of 220 °C and alloying with Mn increase the strength characteristics and decrease the ductility of studied alloys. A slight anisotropy of properties in the longitudinal and transverse directions was also observed. Measurements of corrosion properties revealed that the addition of Mn to Mg-Zn-Ca alloys reduces the corrosion rate. On the other hand, increasing the Zn content in alloys increases the corrosion rate. The extrusion temperature practically does not affect the corrosion rate. Acknowledgement: The authors gratefully acknowledge the financial support of the Ministry of Science and Higher Education of the Russian Federation in the framework of Increase Competitiveness Program of NUST «MISiS» (No K2-2019-008), implemented by a governmental decree dated 16th of March 2013, N 211.

Keywords: biocompatibility, hot extrusion, magnesium alloys, severe plastic deformation, properties

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Authors: A. Chari, A. El Bouari, B. Orayech, A. Faik, J. M. Igartua

Abstract:

The phosphate is a natural resource of great importance in Morocco. In order to exploit this wealth, synthesis and studies of new a material based phosphate, were carried out. The apatite structure present o lot of characteristics, One of the main characteristics is to allow large and various substitutions for both cations and anions. Beside their biological importance in hard tissue (bone and teeth), apatites have been extensively studied for their potential use as fluorescent lamp phosphors or laser host materials.The apatite have interesting possible application fields such as in medicine as materials of bone filling, coating of dental implants, agro chemicals as artificial fertilizers. The LiPb2Ca2(PO4)3 was synthesized by the solid-state method, its crystal structure was investigated by Rietveld analysis using XRPD data. This material crystallizes with a structure of lacunar apatite anion deficit. The LiPb2Ca2(PO4)3 is hexagonal apatite at room temperature, adopting the space group P63/m (ITA No. 176), Rietveld refinements showed that the site 4f is shared by three cations Ca, Pb and Li. While the 6h is occupied by the Pb and Li cations. The structure can be described as built up from the PO4 tetrahedra and the sixfold coordination cavities, which delimit hexagonal tunnels along the c-axis direction. These tunnels are linked by the cations occupying the 4 f sites. Raman and Infrared spectroscopy analyses were carried out. The observed frequencies were assigned and discussed on the basis of unit-cell group analysis and by comparison to other apatite-type materials.

Keywords: apatite, Lacunar, crystal structure, Rietveldmethod, LiPb2Ca2(PO4)3, Phase transition

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Authors: Yi-Chun Wu, Nai-Yun Chang, Chuan LI

Abstract:

This study investigates a feasible range of composition for the mixture of gelatin and polyvinyl alcohol to form nanofibers by electrospinning. Gelatin, one of the most available naturally derived hydrogels of amino acids, is a popular choice for food additives, cosmetic ingredients, biomedical implants, or dressing of its non-toxic and biodegradable nature. Nevertheless, synthetic hydrogel polyvinyl alcohol has long been used as a thickening agent for adhesion purposes. Many biomedical devices are also containing polyvinyl-alcohol as a major content, such as eye drops and contact lenses. To discover appropriate compositions of gelatin and polyvinyl-alcohol for electrospun nanofibers, polymer solutions of different volumetric ratios between gelatin and polyvinyl alcohol were prepared for electrospinning. The viscosity, surface tension, pH value, and electrical conductance of polymer solutions were measured. On the nanofibers, the vibrational modes of molecular structures in nanofibers were investigated by Fourier-transform infrared spectroscopy. The morphologies and surface chemical elements of fibers were examined by the scanning electron microscope and the energy-dispersive X-ray spectroscopy. The hydrophilicity of nanofiberswas evaluated by the water contact angles on the surface of the fibers. To further test the biotoxicity of nanofibers, an in-vitro 3T3 fibroblasts culture further tested the biotoxicity of the electrospun nanofibers. Throughstatistical analyses of the experimental data, it is found that the polyvinyl-alcohol rich composition (the volumetric ratio of gelatin/polyvinyl-alcohol < 1) would be a preferable choice for the formation of nanofibers by the current setup of electrospinning. These electrospun nanofibers tend to be hydrophilic with no biotoxicity threat to the 3T3 fibroblasts.

Keywords: gelatin, polyvinyl-alcohol, nanofibers, electrospinning, spin coating

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Authors: Sara Mercedes Barroso Pinzón, Antonio Javier Sanchéz Herencia, Begoña Ferrari, Álvaro Jesús Castro

Abstract:

The current need for durable implants and bone substitutes characterised by biocompatibility, bioactivity and mechanical properties, without immunological rejection, is a major challenge for scientists. Hydroxyapatite (HAp) has been considered for decades as an ideal biomaterial for bone regeneration due to its chemical and crystallographic similarity to the mineral structure bioapatites. However, the lack of trace elements in the hydroxyapatite structure gives it very low mechanical and biological properties. In this sense, the objective of the research is to address the synthesis of hydroxyapatite with Mg from phosphate rock from sedimentary deposits in the central-eastern region of Colombia, taking advantage of the release of the species contained as natural precursors of Ca, P and Mg. The minerals present were studied, fluorapatite as the mineral of interest associated with mineralogical species of magnesium carbonates and quartz. The chemical and mineralogical composition was determined by X-ray fluorescence (XRF) and X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX); as well as the evaluation of the surface physicochemical properties of zeta potential (PZC), with the aim of studying the surface behaviour of the microconstituents present in the phosphate rock and to elucidate the synergistic mechanism between the minerals and establish the optimum conditions for the wet concentration process. From the products obtained and characterised by XRD, XRF, SEM, FTIR, RAMAN, HAp-Mg biocomposite scaffolds are fabricated and the influence of Mg on the morphometric parameters, mechanical and biological properties of the designed materials is evaluated.

Keywords: phosphate rock, hydroxyapatite, magnesium, biomaterials

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Authors: Tuba Kizilirmak

Abstract:

Distinct properties of porous metamaterials have been largely processed for biomedicine requiring a three-dimensional (3D) porous structure engaged with fine mechanical features, biodegradation ability, and biocompatibility. Applications of metamaterials are (i) porous orthopedic and dental implants; (ii) in vitro cell culture of metamaterials and bone regeneration of metamaterials in vivo; (iii) macro-, micro, and nano-level porous metamaterials for sensors, diagnosis, and drug delivery. There are some specific properties to design metamaterials for tissue engineering. These are surface to volume ratio, pore size, and interconnection degrees are selected to control cell behavior and bone ingrowth. In this study, additive manufacturing technique selective laser melting will be used to print the scaffolds. Selective Laser Melting prints the 3D components according to designed 3D CAD models and manufactured materials, adding layers progressively by layer. This study aims to design metamaterials with Ti6Al4V material, which gives benefit in respect of mechanical and biological properties. Ti6Al4V scaffolds will support cell attachment by conferring a suitable area for cell adhesion. This study will control the osteoblast cell attachment on Ti6Al4V scaffolds after the determination of optimum stiffness and other mechanical properties which are close to mechanical properties of bone. Before we produce the samples, we will use a modeling technique to simulate the mechanical behavior of samples. These samples include different lattice models with varying amounts of porosity and density.

Keywords: additive manufacturing, titanium lattices, metamaterials, porous metals

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Authors: Jung Park, Anca Mazare, Klaus Von Der Mark, Patrik Schmuki

Abstract:

In clinical application of TiO2 implants on tooth and hip replacement, migration, adhesion and differentiation of neighboring mesenchymal stem cells onto implant surfaces are critical steps for successful bone regeneration. In a recent decade, accumulated attention has been paid on nanoscale electrochemical surface modifications on TiO2 layer for improving bone-TiO2 surface integration. We generated, on titanium surfaces, self-assembled layers of vertically oriented TiO2 nanotubes with defined diameters between 15 and 100 nm and here we show that mesenchymal stem cells finely sense TiO2 nanotubular geometry and quickly decide their cell fate either to differentiation into osteoblasts or to programmed cell death (apoptosis) on TiO2 nanotube layers. These cell fate decisions are critically dependent on nanotube size differences (15-100nm in diameters) of TiO2 nanotubes sensing by integrin clustering. We further demonstrate that nanoscale topography-sensing is feasible not only in mesenchymal stem cells but rather seems as generalized nanoscale microenvironment-cell interaction mechanism in several cell types composing bone tissue network including osteoblasts, osteoclast, endothelial cells and hematopoietic stem cells. Additionally we discuss the synergistic effect of simultaneous stimulation by nanotube-bound growth factor and nanoscale topographic cues on enhanced bone regeneration.

Keywords: TiO2 nanotube, stem cell fate decision, nano-scale microenvironment, bone regeneration

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