Search results for: chitosan/ nHA/ Na ₂CO₃ composite

Authors: Anna Zimoch-Korzycka, Dominika Kulig, Andrzej Jarmoluk

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The aim of this study was to obtain chitooligosaccharides from chitosan with better functional properties using three different enzyme preparations and compare the products of enzymatic hydrolysis. Commercially available cellulase (CL), xylanase (X) and chitosanase (CS) preparations were used to investigate hydrolytic activity on chitosan (CH) with low molecular weight and DD of 75-85%. It has been reported that CL and X have side activities of other enzymes, such as β-glucanase or β-glucosidase. CS enzyme has a foreign activity of chitinase. Each preparation was used in 1000 U of activity and in the same reaction conditions. The degree of deacetylation and molecular weight of chitosan were specified using titration and viscometric methods, respectively. The hydrolytic activity of enzymes preparations on chitosan was monitored by dynamic viscosity measurement. After 4 h reaction with stirring, solutions were filtered and chitosan oligomers were isolated by methanol solution into two fractions: precipitate (A) and supernatant (B). A Fourier-transform infrared spectroscopy was used to characterize the structural changes of chitosan oligomers fractions and initial chitosan. Furthermore, the solubility of lyophilized hydrolytic mixture (C) and two chitooligomers fractions (A, B) of each enzyme hydrolysis was assayed. The antioxidant activity of chitosan oligomers was evaluated as DPPH free radical scavenging activity. The dynamic viscosity measured after addition of enzymes preparation to the chitosan solution decreased dramatically over time in the sample with X in comparison to solution without the enzyme. For mixtures with CL and CS, lower viscosities were also recorded but not as low as the ones with X. A and B fractions were characterized by the most similar viscosity obtained by the xylanase hydrolysis and were 15 mPas and 9 mPas, respectively. Structural changes of chitosan oligomers A, B, C and their differences related with various enzyme preparations used were confirmed. Water solubility of A fractions was not possible to filter and the result was not recorded. Solubility of supernatants was approximately 95% and was higher than hydrolytic mixture. It was observed that the DPPH radical scavenging effect of A, B, C samples is the highest for X products and was approximately 13, 17, 19% respectively. In summary, a mixture of chitooligomers may be useful for the design of edible protective coatings due to the improved biophysical properties.

Keywords: cellulase, xylanase, chitosanase, chitosan, chitooligosaccharides

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Authors: Marzieh Fotovvat, Farzaneh Najafi, Ramazan Ali Khavari-Nejad, Daryush Talei, Farhad Rejali

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Salvia leriifolia Benth. is one of the valuable and perennial medicinal plants of the Lamiaceae family, geographically growing in the south and tropical regions of Khorassan and Semnan provinces in Iran. In recent years, several medicinal properties such as antimicrobial, antifungal, anti-diabetic, analgesic, and anti-inflammatory effects have been reported from this plant. The use of elicitors such as chitosan and Arbuscular mycorrhizal fungi (AMF) symbiosis are the main methods for increasing the production of secondary metabolites, growth, and physiological factors in plants. The main aim of this study was to investigate the effects of foliar spraying applications by chitosan and/or the contribution of AMF (Glomus interaradices) on some growth factors and chlorophyll content of S. leriifolia under glasshouse conditions. The sterilized seeds were germinated by placing them into a cocopeat. After one month, seedlings that were in the 2-4 leaf stage were transferred to plastic pots (garden soil and pumice at 2:1) with or without mycorrhizal fungi. Chitosan (0, 50, 100, 200, and 400 mg L-1) was sprayed four times in the fourth month of the vegetative period. The results showed that fresh leaf weight, fresh root weight, root height, and chlorophyll content could change in the plant treated with chitosan and AMF symbiosis. So that the highest chlorophyll content and fresh weight of roots and leaves were observed in the interaction of chitosan and G. interaradices. In general, by optimizing the chitosan concentration and the use of appropriate AMF symbiosis, it is possible to improve the growth and quality of the medicinal plant S. leriifolia.

Keywords: chitosan, chlorophyll, growth factors, mycorrhiza

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Authors: Georgia M. Michailidou, Nina-Maria S. Ainali, Eleftheria C. Xanthopoulou, Dimitrios N. Bikiaris

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Polysaccharides are polymeric materials derived from nature. They are extensively used in pharmaceutical technology due to their low cost, their ready availability and their low toxicity. Chitosan is the product derived from the deacetylation of chitin usually obtained from arthropods. It is a linear polysaccharide which is composed of repeated units of N-deacetylated amino groups and some N-acetylated groups residues. Due to its excellent biological properties, it is an attractive natural polymer. It is biocompatible with low toxicity and complete biodegradability. Although it has excellent properties, the chemical modification of its structure results in new derivatives with ameliorated and more improved properties compared to the initial polymer. This is the exact purpose of the present study in which chitosan was modified with three different monomers, namely trans-aconitic acid, succinic anhydride and 2-hydroxyethyl acrylate. In chitosan’s modification with trans aconitic acid, EDC was utilized as an activator of the carboxylic groups of the monomer, and then a coupling reaction with the amino groups took place. Succinic anhydride reacted with chitosan through a ring opening reaction while 2-hydroxyethyl acrylate reacted through the addition of chitosan’s amino group to the double bond of the monomer. Through FTIR and NMR measurements the success of each reaction was confirmed, and the new structures of the derivatives were verified. X-ray diffraction was utilized in order to examine the effect of the modifications in chitosan’s crystallinity. Finally, swelling tests were conducted in order to assess the improved ability of the new polymeric materials to absorb water. Our results support the successful modification of chitosan’s macromolecular chains in all three reactions. Furthermore, the new derivatives appear to be amorphous concerning their crystallinity and have great ability in absorbing water.

Keywords: chitosan, derivatives, modification, polysaccharide

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Authors: Othman M. Hakami, Abdul Jabbar Al-Rajab

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Occurrence of heavy metals in water resources increased in the recent years albeit at low concentrations. Lead (PbII) is among the most important inorganic pollutants in ground and surface water. However, removal of this toxic metal efficiently from water is of public and scientific concern. In this study, we developed a rapid and efficient removal method of lead from water using chitosan/magnetite nanoparticles. A simple and effective process has been used to prepare chitosan/magnetite nanoparticles (NPs) (CS/Mag NPs) with effect on saturation magnetization value; the particles were strongly responsive to an external magnetic field making separation from solution possible in less than 2 minutes using a permanent magnet and the total Fe in solution was below the detection limit of ICP-OES (<0.19 mg L-1). The hydrodynamic particle size distribution increased from an average diameter of ~60 nm for Fe3O4 NPs to ~75 nm after chitosan coating. The feasibility of the prepared NPs for the adsorption and desorption of Pb(II) from water were evaluated using Chitosan/Magnetite NPs which showed a high removal efficiency for Pb(II) uptake, with 90% of Pb(II) removed during the first 5 minutes and equilibrium in less than 10 minutes. Maximum adsorption capacities for Pb(II) occurred at pH 6.0 and under room temperature were as high as 85.5 mg g-1, according to Langmuir isotherm model. Desorption of adsorbed Pb on CS/Mag NPs was evaluated using deionized water at different pH values ranged from 1 to 7 which was an effective eluent and did not result the destruction of NPs, then, they could subsequently be reused without any loss of their activity in further adsorption tests. Overall, our results showed the high efficiency of chitosan/magnetite nanoparticles (NPs) in lead removal from water in controlled conditions, and further studies should be realized in real field conditions.

Keywords: chitosan, magnetite, water, treatment

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Authors: L. Sasikala, Bhaarathi Dhurai

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Increase in antibiotic resistance bacteria leads to the development of active wound dressings, which absorb any bodily fluid, evaporation of moisture at a certain rate and can be easily removed after healing. Natural materials like chitosan, herbs, and honey have number of active materials present in them to accelerate wound healing and to arrest wound in infections. Hence with the advantages of biomaterials, a film was prepared using chitosan and honey. There are a lot of practical considerations with respect to honey. Honey exerts many beneficial actions on the wound surface only when it remains. The attempts to hold honey on the surface of the wound remain a question because honey becomes a very runny liquid when it comes to body temperature. Hence, this research was focused on development of a new form of wound dressing, by holding honey on the wound surface in different form and also which has a combined effect of manuka (Leptospermum scoparium) honey and chitosan. Chitosan-honey film was prepared using casting technique. Films were prepared in different variations; with acetic acid and with lactic acid; with and without honey. In summary, the film produced from 2% chitosan- 1% lactic acid as a solvent, with 10% honey shows optimum inclined values in all the tests, like thickness, folding endurance, weight, water vapor transmission, tensile strength, swelling ratio and antimicrobial activity, with specific reference to wound dressings. The film has water vapor transmission of 1680 g/m²/day, water absorption of 225%, tensile strength of 39.1N/mm² and elongation of 50.3%. There is a notable inhibition zone of 29 mm against S. aureus and 24 mm against E. coli in the case of chitosan-lactic acid-honey film. The film also arrests, microbes transmitting from the outside environment to wound bed, which can be used as an effective wound dressing material.

Keywords: casting technique, chitosan, honey, film, wound dressings

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Authors: Ankit Patil, Tushar D. Deshpande, Yogesh M. Nimdeo

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Pickering emulsions (PE) were developed in response to increased demand for organic, eco-friendly, and biocompatible products. These emulsions are usually stabilized by solid particles. In this research, we created chitosan-based sunflower oil-in-water (O/W) PE without the need for a surfactant. In our work, we employed chitosan, a biopolymer derived from chitin, as a stabilizer. This decision was influenced by chitosan's biocompatibility and biodegradability, as well as its anti-inflammatory and antibacterial capabilities. It also has other functional properties, such as antioxidant activity, a probiotic delivery mechanism, and the ability to encapsulate bioactive compounds. The purpose of this study was to govern key parameters that can be changed to obtain stable PE, such as the concentration of chitosan (0.3-0.5 wt.%), the concentration of oil (0.8-1 vol%), the pH of the emulsion (3-7) manipulated by the addition of 1M HCl/ 4M NaOH, and the amount of electrolyte (NaCl-0-300mM) added to increase or decrease ionic strength. A careful combination of these properties resulted in the production of the most stable and optimal PE. Particle size study found that emulsions with pH 6, 0.4% chitosan, and 300 mM salts were exceptionally stable, with droplet size 886 nm, PI of 0.1702, and zeta potential of 32.753.83 mV. It is fair to infer that when ionic strength rises, particle size, zeta potential, and PI value decrease. A lower PI value suggests that emulsion nanoparticles are more homogeneous. The addition of sodium chloride increases the ionic strength of the emulsion, facilitating the formation of more compact and ordered particle layers. These findings provide light on the creation of stimulus-responsive chitosan-based PE capable of encapsulating bioactive materials, functioning as antioxidants, and serving as food-grade emulsifiers.

Keywords: pickering emulsion, biocompatibility, eco-friendly, chitosan

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Authors: Mahmoud H. Abu Elella, Riham R. Mohamed, Magdy W. Sabaa

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Firstly, synthesis of N-Quaternized Chitosan (NQC), then it was proven by FTIR and 1H-NMR analysis. The degree of quaternization(DQ 35% ) was determined by equation. Secondly, synthesis of cross-linked hydrogels composed of NQC and poly (vinyl alcohol) (PVA) in different weight ratios in presence of glutaraldehyde (GA) as cross-linking agent. Characterization of the prepared hydrogels was done using FTIR, SEM, XRD,and TGA. Swellability in simulated body fluid (SBF) solutions applied on NQC / PVA hydrogels and swelling rate(Wt%) and metal ions uptake was done on it.

Keywords: hydrogel, metal ions uptake, N-quaternized chitosan, poly (vinyl alcohol), swellability

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Authors: Bi Wa, Su-Yeon Kwon, Ik-Joong Kang

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Surface-enhanced Raman Scattering (SERS) as the principle for enhancing Raman scattering by molecules adsorbed on rough metal surfaces or by nanostructures is used to detect the concentration change of γ-Aminobutyric Acid (GABA). GABA is the mainly inhibitory neurotransmitter in the mammalian central nervous system in the human body. It plays such significant role in reducing neuronal excitability throughout the nervous system. In this case, the Mercaptopropionic Acid (MPA) is used to modified chitosan –gold nanoshell, which enhances the absorption between GABA and Chitosan-gold nanoshell. The sulfur end of the MPA is linked to gold which is the surface of the chitosan nanoparticles via the very strong S–Au bond, while a functional group (carboxyl group) attached to GABA. The controlling of particles’ size and the surface morphology are also the important factors during the whole experiment. The particle around 100nm is using to link to MPA, and the range of GABA from 1mM to 30mM was detected by the Raman Scattering to obtain the calibrate curve. In this study, DLS, SEM, FT-IR, UV, SERS were used to analyze the products to obtain the conclusion.

Keywords: chitosan-gold nanoshell, mercaptopropionic acid, γ-aminobutyric acid, surface-enhanced raman scattering

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Authors: Talat Baran

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Palladium-catalyzed Suzuki coupling reactions are powerful ways for synthesis of biaryls compounds and so far different palladium sources as have been used in catalyst systems. However, the high cost of the ligands using as support materials for palladium ion and so researchers have explored alternative low-cost support materials such as silica, cellule and zeolite. A natural polymer chitosan is suitable for support material because of it unique properties such as eco-friendly, renewable, abundant, low cost, biodegradable and it has free reactive -NH2 and –OH groups. Especially, pendant amino groups of chitosan can easily react with carbonyl groups of aldehyde or ketone by Schiff base formation and thus palladium ions can coordinate with imine groups of Schiff base. This purpose, in this study, firstly a new chitosan Schiff base supported palladium (II) catalyst was synthesized and its chemical structure was characterized with FT-IR, SEM/EDAX, XRD, TG-DTG, ICP-OES and magnetic moment techniques. Then catalytic performance of the catalyst was investigated in Suzuki cross coupling reactions under simple and fast microwave heating methods. Also, recycle activity of palladium catalyst was tested under optimum condition and the catalyst showed long life time. At the end of catalytic performance tests of chitosan supported palladium (II) catalysts indicated high turnover numbers, turnover frequency and selectivity with very small loading catalyst

Keywords: catalyst, chitosan, Schiff base, Suzuki coupling

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Authors: Chao Ding, Jun Shi, Huiping Deng

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This study reports the preparation of a new type yeast-chitosan bio-microcapsule coating sodium alginate and chitosan, with good biocompatibility and mechanical strength. Focusing on the optimum preparation conditions of bio-microcapsule, a dynamic test of yeast-chitosan bio-microcapsule combined with ultrafiltration membrane was established to evaluate both the removal efficiency of major pollutants from raw water and the applicability of this system. The results of orthogonal experiments showed that the optimum preparation procedure are as follows: mix sodium alginate solution (3%) with bacteria liquid in specific proportion, drop in calcium chloride solution (4%) and solidify for 30 min; put the plastic beads into chitosan liquid (1.8%) to overlay film for 10 min and then into glutaraldehyde solution (1%) to get cross-linked for 5 min. In dynamic test, the microcapsules were effective as soon as were added in the system, without any start-up time. The removal efficiency of turbidity, ammonia nitrogen and organic matter was 60%, 80%, and 40%. Besides, the bio-microcapsules were prospective adsorbent for heavy metal; they adsorb Pb and Cr⁶⁺ in water while maintaining high biological activity to degrade ammonia nitrogen and small molecular organics through assimilation. With the presence of bio-microcapsules, the internal yeast strains’ adaptability on the external environment and resistance ability on toxic pollutants will be increased.

Keywords: ammonia nitrogen, bio-microcapsules, ultrafiltration membrane, yeast-chitosan

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Authors: Farramae Francisco, Rhoda Mae Simora, Sharon Nunal

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Deproteination and demineralization efficiencies of shrimp waste using two Lactobacillus species treated with different carbohydrate sources for chitin production, its chemical conversion to chitosan and the quality of chitin and chitosan produced were determined. Using 5% glucose and 5% cassava starch as carbohydrate sources, pH slightly increased from the initial pH of 6.0 to 6.8 and 7.2, respectively after 24 h and maintained their pH at 6.7 to 7.3 throughout the treatment period. Demineralization (%) in 5 % glucose and 5 % cassava was highest during the first day of treatment which was 82% and 83%, respectively. Deproteination (%) was highest in 5% cassava starch on the 3rd day of treatment at 84.4%. The obtained chitin from 5% cassava and 5% glucose had a residual ash and protein below 1% and solubility of 59% and 44.3%, respectively. Chitosan produced from 5% cassava and 5% glucose had protein content below 0.05%; residual ash was 1.1% and 0.8%, respectively. Chitosan solubility and degree of deacetylation were 56% and 33% in 5% glucose and 48% and 29% in 5% cassava, respectively. The advantage this alternative technology offers over that of chemical extraction is large reduction in chemicals needed thus less effluent production and generation of a protein-rich liquor, although the demineralization process should be improved to achieve greater degree of deacetylation.

Keywords: alternative carbon source, bioprocessing, lactic acid bacteria, waste utilization

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Authors: N. Valderrama, W. Albarracín, N. Algecira

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It was studied the effect of the inclusion of thyme and rosemary essential oils into chitosan films, as well as the microbiological and physical properties when storing chitosan film with and without the mentioned inclusion. The film forming solution was prepared by dissolving chitosan (2%, w/v), polysorbate 80 (4% w/w CH) and glycerol (16% w/w CH) in aqueous lactic acid solutions (control). The thyme (TEO) and rosemary (REO) essential oils (EOs) were included 1:1 w/w (EOs:CH) on their combination 50/50 (TEO:REO). The films were stored at temperatures of 5, 20, 33°C and a relative humidity of 75% during four weeks. The films with essential oil inclusion did not show an antimicrobial activity against strains. This behavior could be explained because the chitosan only inhibits the growth of microorganisms in direct contact with the active sites. However, the inhibition capacity of TEO was higher than the REO and a synergic effect between TEO:REO was found for S. enteritidis strains in the chitosan solution. Some physical properties were modified by the inclusion of essential oils. The addition of essential oils does not affect the mechanical properties (tensile strength, elongation at break, puncture deformation), the water solubility, the swelling index nor the DSC behavior. However, the essential oil inclusion can significantly decrease the thickness, the moisture content, and the L* value of films whereas the b* value increased due to molecular interactions between the polymeric matrix, the loosing of the structure, and the chemical modifications. On the other hand, the temperature and time of storage changed some physical properties on the chitosan films. This could have occurred because of chemical changes, such as swelling in the presence of high humidity air and the reacetylation of amino groups. In the majority of cases, properties such as moisture content, tensile strength, elongation at break, puncture deformation, a*, b*, chrome, ΔE increased whereas water resistance, swelling index, L*, and hue angle decreased.

Keywords: chitosan, food additives, modified films, polymers

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Authors: Eman Alzahrani

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Efficient extraction of proteins by removing interfering materials is necessary in proteomics, since most instruments cannot handle such contaminated sample matrices directly. In this study, chitosan-coated magnetic nanoparticles (CS-MNPs) for purification of myoglobin were successfully fabricated. First, chitosan (CS) was prepared by a deacetylation reaction during its extraction from shrimp-shell waste. Second, magnetic nanoparticles (MNPs) were synthesised, using the coprecipitation method, from aqueous Fe2+ and Fe3+ salt solutions by the addition of a base under an inert atmosphere, followed by modification of the surface of MNPs with chitosan. The morphology of the formed nanoparticles, which were about 23 nm in average diameter, was observed by transmission electron microscopy (TEM). In addition, nanoparticles were characterised using X-ray diffraction patterns (XRD), which showed the naked magnetic nanoparticles have a spinel structure and the surface modification did not result in phase change of the Fe3O4. The coating of MNPs was also demonstrated by scanning electron microscopy (SEM) analysis, energy dispersive analysis of X-ray spectroscopy (EDAX), and Fourier transform infrared (FT-IR) spectroscopy. The adsorption behaviour of MNPs and CS-MNPs towards myoglobin was investigated. It was found that the difference in adsorption capacity between MNPs and CS-MNPs was larger for CS-MNPs. This result makes CS-MNPs good adsorbents and attractive for using in protein extraction from biological samples.

Keywords: chitosan, magnetic nanoparticles, coprecipitation, adsorption

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Authors: Sanjay Singh, Swati Jaiswal, Prashant Mishra

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Nanoparticle based formulations of drug delivery systems have shown their potential in improving the performance of existing drugs and have opened avenues for new therapies. Calendula extract is a low cost, wide spectrum bioactive material that has been used for a long term therapy of various infections. Aim: The aim of this study was to develop Calendula officinalis extract based nanoformulations and to study the antibacterial activity of either Calendula extract loaded chitosan nanoparticles or Calendula extract coated silver nanoparticles for increased bioavailability and their long term effect. Methods: Chitosan nanoparticles were prepared by the process of ionotropic gelation, based on interaction between the negative groups of tri polyphosphate (TPP) and positively charged amino groups of chitosan. The size of the Calendula extract-loaded chitosan particles was determined using dynamic light scattering and scanning electron microscopy. Antibacterial activities of these formulations were determined based on minimum inhibitory concentration and time kill studies. In addition, silver nanoparticles were also synthesized in the presence of Calendula extract and characterized by UV visible spectrum, DLS and XRD. Experiments were conducted on 96-plates against two Gram-positive bacteria; Staphylococcus aureus and Bacillus subtilis two Gram-negative bacteria; Escherichia coli and Pseudomonas aeruginosa. Results: Results demonstrated time dependent antibacterial activity against different microbes studied. Both Calendula extract and Calendula extract loaded chitosan nanoparticles have shown good antimicrobial activity against both Gram positive and Gram negative bacteria. Conclusion: Calendula extract loaded chitosan nanoparticles and calendula extract coated silver nanoparticles are potential antibacterial for their long term antibacterial effects.

Keywords: antibacterial, Calendula extract, chitosan nanoparticles, silver nanoparticles

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Authors: Akbar Esmaeili, Azadeh Asgari

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Essential oils’ unique and practical properties have been widely reported in recent years. Still, the sensitivity of critical oils to environmental factors and their poor solubility in aqueous solutions have limited their use in industries. Therefore, we encapsulated C. copticum essential oil in chitosan nanoparticles by emulsion-ionic gelation with sodium tripolyphosphate and sodium hexametaphosphate cross-linkers. The nanoparticles showed a round shape with an average size of 30-80 nm and a regular distribution. The release profile in the laboratory environment showed a burst in the initial release and then a stable release of C. copticum essential oil from chitosan nanoparticles at different pH. Antioxidant and antibacterial properties of C. copticum essential oil before and after the encapsulation process were evaluated by 2,2-diphenyl-1-picrylhydrazyl radical and disc diffusion methods, respectively. The results showed that the encapsulation of C. copticum essential oil in chitosan nanoparticles could protect its quality and bioactive compounds and improve the properties of the crucial oil.

Keywords: essential oils, Carum copticum, biological activities, nanotechnology

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Authors: Preeti Pal, Anjali Pal

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Chitosan is an effective sorbent for removal of contaminants from wastewater. However, the ability of pure chitosan is specific because of its cationic charge. It causes repulsion in the removal process of various cationic charged molecules. The present study has been carried out for the successful removal of Pb²⁺ ions from aqueous solution by modified chitosan beads. Surface modification of chitosan (CS) beads was performed by using the anionic surfactant (AS), sodium dodecyl sulfate (SDS). Micelle aggregation property of SDS has been utilized for the formation of bilayer over the CS beads to produce surfactant modified chitosan (SMCS) beads. Prepared adsorbents were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) in order to find out their composition and surface morphology. SMCS beads, when compared to the pure CS beads, showed three times higher adsorption. This higher adsorption is believed to be due to the adsolubilization of Pb²⁺ ions on SDS bilayer. This bilayer provides more adsorption sites for quick and effective removal of Pb²⁺ ions from the aqueous phase. Moreover, the kinetic and adsorption isotherm models were employed to the obtained data for the description of the lead adsorption processes. It was found that the removal kinetics follows pseudo-second order model. Adsorption isotherm data fits well to the Langmuir model. The maximum adsorption capacity obtained is 100 mg/g at the dosage of 0.675 g/L for 50 mg/L of Pb²⁺. The adsorption capacity is subject to increase with increasing the Pb²⁺ ions concentration in the solution. The results indicated that the prepared hydrogel beads are efficient adsorbent for removal of Pb²⁺ ions from the aqueous medium.

Keywords: adsolubilisation, anionic surfactant, bilayer, chitosan, Pb²⁺

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Authors: Courtney Evans, Yuto Morimitsu, Tsubasa Hisadome, Futo Inomoto, Masahiro Yoshida, Takayuki Takei

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Hydrogels are useful biomaterials due to their highly biocompatible nature and their ability to absorb large quantities of liquid and mimic soft tissue. They are often used as therapeutic drug delivery systems. However, it is sometimes difficult to sustain controlled release when using hydrophobic medicines, as hydrogels are frequently hydrophilic. As such, this research shows the success of chitosan hydrogels modified through hydrophobic interaction. This was done through the imide bonding of the alkyl groups in fatty aldehydes and the amino groups in chitosan, followed by reductive animation. The resulting cryogels could be optimized for strength as well as sorption and desorption (of a hydrophobic dye used to mimic hydrophobic medicine) by varying the alkyl chain length and the substitution degree of the fatty aldehyde. Optimized cryogels showed potential as biomedical materials, particularly as drug delivery systems.

Keywords: biomedical materials, chitosan, drug carriers, hydrophobic modification

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Authors: F. A. Abdel-Mohdy, M. K. El-Bisi, A. Abou-Okeil, A. A. Sleem, S. El-Sabbagh, Kawther El-Shafei, Hoda S. El-Sayed, S. M. ElSawy

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Chitosan/ polyacrylic acid membranes containing different amounts of Al2(SO4) and/or TiO2 were prepared. The prepared membranes were characterized by measuring mechanical properties, such as tensile strength and elongation at break, swelling properties, antimicrobial properties against gram-positive and gram-negative bacteria and blood clotting. The results obtained indicate that the presence of Al2(SO4) and TiO2 in the membrane formulations have an incremental effect on the antimicrobial properties and blood clotting in albino rate.

Keywords: Chitosan, acrylic acid, antibacterial, blood clotting, membrane

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Authors: Gyati Shilakari Asthana, Abhay Asthana

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Purpose: The therapeutic potential of oligonucleotide (ODN) is primarily dependent upon its safe and efficient delivery to specific cells overcoming degradation and maximizing cellular uptake in vivo. The present study is focused to design low molecular weight chitosan nanoconstructs to meet the requirements of safe and effectual delivery of ODNs. LMW-chitosan is a biodegradable, water soluble, biocompatible polymer and is useful as a non-viral vector for gene delivery due to its better stability in water. Methods: LMW chitosan ODN nanoparticles (CHODN NPs) were formulated by self assembled method using various N/P ratios (moles ratio of amine groups of CH to phosphate moieties of ODNs; 0.5:1, 1:1, 3:1, 5:1 and 7:1) of CH to ODN. The developed CHODN NPs were evaluated with respect to gel retardation assay, particle size, zeta potential and cytotoxicity and transfection efficiency. Results: Complete complexation of CH/ODN was achieved at the charge ratio of 0.5:1 or above and CHODN NPs displayed resistance against DNase I. On increasing the N/P ratio of CH/ODN, particle size of the NPs decreased whereas zeta potential (ZV) value increased. No significant toxicity was observed at all CH concentrations. The transfection efficiency was increased on increasing N/P ratio from 1:1 to 3:1, whereas it was decreased with further increment in N/P ratio upto 7:1. Maximum transfection of CHODN NPs with both the cell lines (Raw 267.4 cells and Hela cells) was achieved at N/P ratio of 3:1. The results suggest that transfection efficiency of CHODN NPs is dependent on N/P ratio. Conclusion: Thus the present study states that LMW chitosan nanoparticulate carriers would be acceptable choice to improve transfection efficiency in vitro as well as in vivo delivery of oligonucleotide.

Keywords: LMW-chitosan, chitosan nanoparticles, biocompatibility, cytotoxicity study, transfection efficiency, oligonucleotide

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Authors: Xiao-Yin Liu, Liang-Xue Zhou

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Traumatic brain injury (TBI), as a kind of nerve trauma caused by an external force, affects people all over the world and is a global public health problem. Although there are various clinical treatments for brain injury, including surgery, drug therapy, and rehabilitation therapy, the therapeutic effect is very limited. To improve the therapeutic effect of TBI, scaffolds combined with exosomes are a promising but challenging method for TBI repair. In this study, we examined whether a novel 3D-printed collagen/chitosan scaffold/exosomes derived from neural stem cells (NSCs) pretreated with insulin growth factor-1 (IGF-I) scaffolds (3D-CC-INExos) could be used to improve TBI repair and functional recovery after TBI. Our results showed that composite scaffolds of collagen-, chitosan- and exosomes derived from NSCs pretreated with IGF-I (INExos) could continuously release the exosomes for two weeks. In the rat TBI model, 3D-CC-INExos scaffold transplantation significantly improved motor and cognitive function after TBI, as assessed by the Morris water maze test and modified neurological severity scores. In addition, immunofluorescence staining and transmission electron microscopy showed that the recovery of damaged nerve tissue in the injured area was significantly improved by 3D-CC-INExos implantation. In conclusion, our data suggest that 3D-CC-INExos might provide a potential strategy for the treatment of TBI and lay a solid foundation for clinical translation.

Keywords: traumatic brain injury, exosomes, insulin growth factor-1, neural stem cells, collagen, chitosan, 3D printing, neural regeneration, angiogenesis, functional recovery

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Authors: Simone F. Medeiros, Jessica M. Fonseca, Gizelda M. Alves, Danilo M. Santos, Sérgio P. Campana-Filho, Amilton M. Santos

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Stimuli responsive and biocompatible hydrogel nanoparticles have gained special attention as systems for potential applications in controlled release of drugs to improve their therapeutic efficacy while minimizing side effects. In this work, novel solid dispersions based on thermo- and pH-responsive poly(N-vinylcaprolactam-co-itaconic acid-co-ethylene- glycol dimethacrylate) hydrogel nanoparticles embedded in chitosan matrices were prepared via spray drying for controlled release of ketoprofen. Firstly, the hydrogel nanoparticles containing ketoprofen were prepared via precipitation polymerization and their stimuli-responsive behavior, thermal properties, chemical composition, encapsulation efficiency and morphology were characterized. Then, hydrogel nanoparticles with different particles size were embedded into chitosan matrices via spray-drying. Scanning electron microscopy (SEM) analyses were performed to investigate the particles size, dispersity and morphology. Finally, ketoprofen release profiles were studied as a function of pH and temperature. Chitosan/poly(NVCL-co-IA-co-EGDMA)-ketoprofen microparticles presented spherical shape, rough surface and pronounced agglomeration, indicating that hydrogels nanoparticles loaded with ketoprofen modified the surface of chitosan matrix. The maximum encapsulation efficiency of ketoprofen into hydrogel nanoparticles was 57.8% and the electrostatic interactions between amino groups from chitosan and carboxylic groups from hydrogel nanoparticles were able to control ketoprofen release. The hydrogel nanoparticles themselves were capable to retard the release of ketoprofen-loaded until 48h of in vitro release tests, while their incorporation into chitosan matrix achieved a maximum percentage of drug release of 45%, using a mass ratio of chitosan: poly(NVCL-co-IA-co-EGDMA equal to 10:7, and 69%, using a mass ratio of chitosan: poly(NVCL-co-IA-co-EGDMA equal to 5:2.

Keywords: hydrogel nanoparticles, poly(N-vinylcaprolactam-co-itaconic acid-co-ethylene- glycol dimethacrylate), chitosan, ketoprofen, spray-drying

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Authors: Amir Amiri, Naghmeh Morakabati

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During the recent years the six-fold growth of cancer in Iran has led the production of healthy products to become a challenge in the food industry. Due to the young population in the country, the consumption of fast foods is growing. The chemical cancer-causing preservatives are used to produce these products more than the standard; so using an appropriate alternative seems to be important. On the one hand, the plant essential oils show the high antimicrobial potential against pathogenic and spoilage microorganisms and on the other hand they are highly volatile and decomposed under the processing conditions. The study aims to produce the loaded chitosan nanoparticles with different concentrations of savory essential oil to improve the anti-microbial property and increase the resistance of essential oil to oxygen and heat. The encapsulation efficiency was obtained in the range of 32.07% to 39.93% and the particle size distribution of the samples was observed in the range of 159 to 210 nm. The range of Zeta potential was obtained between -11.9 to -23.1 mV. The essential oil loaded in chitosan showed stronger antifungal activity against Rhizopus stolonifer. The results showed that the antioxidant property is directly related to the concentration of loaded essential oil so that the antioxidant property increases by increasing the concentration of essential oil. In general, it seems that the savory essential oil loaded in chitosan particles can be used as a food processor.

Keywords: chitosan, encapsulation, essential oil, nanogel

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Authors: Pyar Singh Jassal, Priti Rani, Rajni Johar

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The adsorption of Pb(II) ions from wastewater using ethylene glycol diglycidyl ether cross-linked magnetic chitosan beads (EGDE-MCB) was carried out by considering a number of parameters. The removal efficiency of the metal ion by magnetic chitosan beads (MCB) and its cross-linked derivatives depended on viz contact time, dose of the adsorbent, pH, temperature, etc. The concentration of Cd( II) at different time intervals was estimated by differential pulse anodic stripping voltammetry (DPSAV) using 797 voltametric analyzer computrace. The adsorption data could be well interpreted by Langmuir and Freundlich adsorption model. The equilibrium parameter, RL values, support that the adsorption (0Keywords: magnetic chitosan beads, ethylene glycol diglycidyl ether, equilibrium parameters, desorption

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Authors: Gyati Shilakari Asthana, Abhay Asthana, Dharm Veer Kohli, Suresh Prasad Vyas

Abstract:

Purpose: The therapeutic potential of oligonucleotide (ODN) is primarily dependent upon its safe and efficient delivery to specific cells overcoming degradation and maximizing cellular uptake in vivo. The present study is focused to design low molecular weight chitosan nanoconstructs to meet the requirements of safe and effectual delivery of ODNs. LMW-chitosan is a biodegradable, water soluble, biocompatible polymer and is useful as a non-viral vector for gene delivery due to its better stability in water. Methods: LMW chitosan ODN nanoparticles (CHODN NPs) were formulated by self-assembled method using various N/P ratios (moles ratio of amine groups of CH to phosphate moieties of ODNs; 0.5:1, 1:1, 3:1, 5:1, and 7:1) of CH to ODN. The developed CHODN NPs were evaluated with respect to gel retardation assay, particle size, zeta potential and cytotoxicity and transfection efficiency. Results: Complete complexation of CH/ODN was achieved at the charge ratio of 0.5:1 or above and CHODN NPs displayed resistance against DNase I. On increasing the N/P ratio of CH/ODN, the particle size of the NPs decreased whereas zeta potential (ZV) value increased. No significant toxicity was observed at all CH concentrations. The transfection efficiency was increased on increasing N/P ratio from 1:1 to 3:1, whereas it was decreased with further increment in N/P ratio upto 7:1. Maximum transfection of CHODN NPs with both the cell lines (Raw 267.4 cells and Hela cells) was achieved at N/P ratio of 3:1. The results suggest that transfection efficiency of CHODN NPs is dependent on N/P ratio. Conclusion: Thus the present study states that LMW chitosan nanoparticulate carriers would be acceptable choice to improve transfection efficiency in vitro as well as in vivo delivery of oligonucleotide.

Keywords: LMW-chitosan, chitosan nanoparticles, biocompatibility, cytotoxicity study, transfection efficiency, oligonucleotide

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Authors: Kittisak Jantanasakulwong, Toshiaki Ougizawa

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Thermoplastic starch (TPS) was prepared by melt-blending of cassava starch with glycerol (70/30 wt%/wt%) at 130 ◦C for 10 min. Chitosan (CTS) was used as a compatibilizer. TPS/CTS blend was melt-blended with maleic anhydride grafted ethylene-1-butene rubber (EB-MAH) in the composition of 80/20 respectively. Addition of CTS in TPS/EB-MAH blend decreased particles size of EB-MAH rubber to 1µm in TPS matrix. Mechanical properties, solubility, swelling property, morphology, and water contact angle of TPS/EB-MAH blend were improved by CTS incorporation. FTIR confirmed a reaction had occurred between amino groups (-NH2) of CTS and the MAH groups of EB-MAH. This reaction and the enhanced miscibility between TPS and CTS improved morphology and properties of the TPS/EB-MAH/CTS blend.

Keywords: thermoplastic starch, rubber, reactive blending, chitosan

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Authors: Hyemi Kim, Jay Kim, Kyunghoon Han, Ra-Yeong Choi, In-Woo Kim, Hyung Joo Suh, Ki-Bae Hong, Sung Hee Han

Abstract:

Chitosan is used in various industries such as food and medical care because it is known to have various functions such as anti-obesity, anti-inflammatory and anti-cancer benefits. Most of the commercial chitosan is extracted from crustaceans. As the harvest rate of snow crabs and red snow crabs decreases and safety issues arise due to environmental pollution, research is underway to extract chitosan from insects. In this study, we used Response Surface Methodology (RSM) to predict the optimal conditions to produce chitosan oligosaccharides from mealworms (MCOS), which can be absorbed through the intestine as low-molecular-weight chitosan. The experimentally confirmed optimal conditions for MCOS production using chitosanase were found to be a substrate concentration of 2.5%, enzyme addition of 30 mg/g and a reaction time of 6 hours. The chemical structure and physicochemical properties of the produced MCOS were measured using MALDI-TOF mass spectra and FTIR spectra. The MALDI-TOF mass spectra revealed peaks corresponding to the dimer (375.045), trimer (525.214), tetramer (693.243), pentamer (826.296), and hexamer (987.360). In the FTIR spectra, commercial chitosan oligosaccharides exhibited a weak peak pattern at 3500-2500 cm-1, unlike chitosan or chitosan oligosaccharides. There was a difference in the peak at 3200~3500 cm-1, where different vibrations corresponding to OH and amine groups overlapped. Chitosan, chitosan oligosaccharide, and commercial chitosan oligosaccharide showed peaks at 2849, 2884, and 2885 cm-1, respectively, attributed to the absorption of the C-H stretching vibration of methyl or methine. The amide I, amide II, and amide III bands of chitosan, chitosan oligosaccharide, and commercial chitosan oligosaccharide exhibited peaks at 1620/1620/1602, 1553/1555/1505, and 1310/1309/1317 cm-1, respectively. Furthermore, the solubility of MCOS was 45.15±3.43, water binding capacity (WBC) was 299.25±4.57, and fat binding capacity (FBC) was 325.61±2.28 and the solubility of commercial chitosan oligosaccharides was 49.04±9.52, WBC was 280.55±0.50, and FBC was 157.22±18.15. Thus, the characteristics of MCOS and commercial chitosan oligosaccharides are similar. The results of investigating the impact of chitosan oligosaccharide on the proliferation of probiotics revealed increased growth in L. casei, L. acidophilus, and Bif. Bifidum. Therefore, the major short-chain fatty acids produced by gut microorganisms, such as acetic acid, propionic acid, and butyric acid, increased within 24 hours of adding 1% (p<0.01) and 2% (p<0.001) MCOS. The impact of MCOS on the overall gut microbiota was assessed, revealing that the Chao1 index did not show significant differences, but the Simpson index decreased in a concentration-dependent manner, indicating a higher species diversity. The addition of MCOS resulted in changes in the overall microbial composition, with an increase in Firmicutes and Verrucomicrobia (p<0.05) compared to the control group, while Proteobacteria and Actinobacteria (p<0.05) decreased. At the genus level, changes in microbiota due to MCOS supplementation showed an increase in beneficial bacteria like lactobacillus, Romboutsia, Turicibacter, and Akkermansia (p<0.0001) while harmful bacteria like Enterococcus, Morganella, Proterus, and Bacteroides (p<0.0001) decreased. In this study, chitosan oligosaccharides were successfully produced under established conditions from mealworms, and these chitosan oligosaccharides are expected to have prebiotic effects, similar to those obtained from crabs.

Keywords: mealworms, chitosan, chitosan oligosaccharide, prebiotics

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Authors: Bingjie Wang, Su-Yeon Kwon, Ik-Joong Kang

Abstract:

A Surface-enhanced Raman Scattering (SERS) as the principle for enhancing Raman scattering by molecules adsorbed on rough metal surfaces or by nanostructures is used to detect the concentration change of γ-Aminobutyric Acid (GABA). As for the gold-chitosan nanoshell, it is made by using chitosan nanoparticles crosslinking with sodium tripolyphosphate(TPP) for the first step to form the chitosan nanoparticles, which would be covered with the gold sequentially. The size of the fabricated product was around 100nm. Based on the method that the sulfur end of the MPA linked to gold can form the very strong S–Au bond, and the carboxyl group, the other end of the MPA, can easily absorb the GABA. GABA is the mainly inhibitory neurotransmitter in the mammalian central nervous system in the human body. It plays such significant role in reducing neuronal excitability throughout the nervous system. When the system formed, it generated SERS, which made a clear difference in the intensity of Raman scattering within the range of GABA concentration. So it is obtained from the experiment that the calibration curve according to the GABA concentration relevant with the SERS scattering. In this study, DLS, SEM, FT-IR, UV, SERS were used to analyze the products to obtain the conclusion.

Keywords: chitosan-gold nanoshell, mercaptopropionic acid, γ-aminobutyric acid, surface-enhanced Raman scattering

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Authors: Ko-Shao Chen, Yun Tsao, Chia-Hsuan Tsen, Chien-Chung Chen, Shu-Chuan Liao

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Electrospun microtube array membranes (MTAMs) made of PLLA (poly-L-lactic acid) have wide potential applications in tissue engineering. However, their surface hydrophobicity and poor biocompatability have limited their further usage. In this study, the surface of PLLA MTAMs were made hydrophilic by introducing extra functional groups, such as peroxide, via an acetic acid plasma (AAP). UV-graft polymerization of acrylic acid (G-AAc) was then used to produce carboxyl group on MTAMs surface, which bonded covalently with chitosan through EDC / NHS crosslinking agents. To evaluate the effects of the surface modification on PLLA MTAMs, water contact angle (WCA) measurement and cell compatibility tests were carried out. We found that AAP treated electrospun PLLA MTAMs grafted with AAc and, finally, with chitosan immobilized via crosslinking agent, exhibited improved hydrophilic and cell compatibility.

Keywords: plasma, EDC/NHS, UV grafting, Chitosan, microtube array membrane (MTAMs)

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Authors: Sang-Myung Jung, Gwang Heum Yoon, Hoo Chul Lee, Hwa Sung Shin

Abstract:

Ceramide, a component of stratum corneum at epidermis, helps to construct a rigid and dense skin barrier to prevent pathogens that cause atopic dermatitis. However, ceramide was too hydrophobic to be directly absorbed into stratum corneum and has risks of side effects by excessive treatment. To overcome the obstacles, ceramide was embedded into PLGA nanoparticles coated with chitosan. PLGA and chitosan have been known as biocompatible materials. PLGA was squeezed when faced with water and pumped ceramide out of PLGA nanoparticle. In addition, the chitosan coating layer helped initial adherence of nanoparticles to skin and regulate ceramide release until removed. This coating was degraded at weakly acid state like skin surface, finally ceramide release could be controlled. Finally, the nanoparticle was demonstrated to be non-cytotoxic and regenerate stratum corneum of atopic dermatitis model. Overall the nanoparticle is suggested as a novel and effective nanodrug to apply atopic dermatitis.

Keywords: nanoparticle, controlled release, atopic dermatitis, chitosan coating, ceramide

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Authors: Akhtar Aman, Abida Raza, Shumaila Bashir, Mehboob Alam

Abstract:

The development of efficient delivery systems remains a major concern in cancer chemotherapy as many efficacious anticancer drugs are hydrophobic and difficult to formulate. Nanomedicines based on drug-loaded amphiphilic glycol chitosan micelles offer potential advantages for the formulation of drugs such as etoposide that may improve the pharmacokinetics and reduce the formulation-related adverse effects observed with current formulations. Amphiphilic derivatives of glycol chitosan were synthesized by chemical grafting of palmitic acid N-hydroxysuccinimide and quaternization to glycol chitosan backbone. To this end, a 7.9 kDa glycol chitosan was modified by palmitoylation and quaternization, yielding a 13 kDa amphiphilic polymer. Micelles prepared from this amphiphilic polymer had a size of 162nm and were able to encapsulate up to 3 mg/ml etoposide. Pharmacokinetic results indicated that the GCPQ micelles transformed the biodistribution pattern and increased etoposide concentration in the brain significantly compared to free drugs after intravenous administration. AUC 0.5-24h showed statistically significant difference in ETP-GCPQ vs. Commercial preparation in liver (25 vs.70, p<0.001), spleen (27 vs.36, p<0.05), lungs (42 vs.136,p<0.001),kidneys(25 vs.70,p< 0.05),and brain(19 vs.9,p<0.001). ETP-GCPQ crossed the blood-brain barrier, and 4, 3.5, 2.6, 1.8, 1.7, 1.5, and 2.5 fold higher levels of etoposide were observed at 0.5, 1, 2, 4, 6, 12, and 24hrs; respectively suggesting these systems could deliver hydrophobic anticancer drugs such as etoposide to tumors but also increased their transport through the biological barriers, thus making it a good delivery system

Keywords: glycol chitosan, micelles, pharmacokinetics, tissue distribution

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