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Performance Enhancement of Chitosan Filled Silver Vanadate Nano-rods
摘要： Silver vanadate nanorods synthesized via chemical precipitation route at room temperature were characterized using UV/Vis. optical electronic spectra, fourier transform infrared (FTIR) spectroscopy, transmission and scanning electron microscopy (TEM, SEM), Zeta potential and X-ray diffraction (XRD). XRD indicates the presence of both β and α phases of silver vanadate. Chitosan samples filled with pre-calculated amounts of synthesized silver vanadate nano-rods were prepared via ordinary casting route. XRD of the prepared polymeric samples reveals amorphous nature and indicating a homogenous distribution of inorganic filler within the matrix without any tendency for crystallization. FTIR shows maintenance of chitosan characteristic bands in all samples. Optical energy gap for both direct and indirect transitions generally indicates a gradual decrease with increasing inorganic filler content. The biological activity against two-gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis), two gram-negative bacteria (Escherichia coli, Pseudomonas aeuroginosa) in addition to one fungus (Candida albicans) were also studied and correlated with both optical energy gap and nanoparticle dopant concentration.
关键词： UV/Vis.,Zeta Potential,Silver vanadate,FTIR,Chitosan,XRD
更新于2025-09-11 14:15:04
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Improvement of electrochemical and structural properties of polycarbazole by simultaneous electrodeposition of chitosan
摘要： Polycarbazole/chitosan composite materials were synthesized electrochemically at various loadings of chitosan (Chi). Their electrochemical, structural, thermal, and morphological characterizations were investigated by cyclic voltammetry, chronoamperometry, electrochemical impedance spectroscopy, Fourier transform infrared spectroscopy, thermal gravimetry, and scanning electron microscopy. Further electrical conductivity was measured using a four-point probe technique. The electrochemical results showed that the electrical conductivity of the polymeric composite (cid:12)lm was increased by increasing the amount of Chi in the electrolyte medium. The as-prepared composite (cid:12)lms exhibited enhanced electrical conductivity and structural properties of polycarbazole due to the presence of Chi in the composite (cid:12)lms.
关键词： chitosan,electropolymerization,electrical properties,Polycarbazole,conducting composite
更新于2025-09-10 09:29:36
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Characterization of Chitosan Particles via Attenuated Total Reflection Fourier Transform Infrared Spectroscopy, Conductometric Titration, Viscosity Average Molecular Weight and X-ray Photoelectron Spectroscopy
摘要： This paper reports the characterization of chitosan particles with a 1.0 × 106 viscosity average molecular weight via attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, conductometric titration, viscosity average molecular weight and X-ray photoelectron spectroscopy. The viscosity average molecular weight (Mv) of chitosan was determined based on conductometric titration. The degree of deacetylation which was calculated with the help of acid base titration method was used to determine k and α values. Then the average viscosity molecular weight was calculated with the help of [η], k and α by the Mark-Houwink Sakurada equation. Molecular and packing structures of the chitosan chains in the crystal were observed using polarized light microscopy to evaluate the crystal structure of the anhydrous form of chitosan.
关键词： XPS,FTIR,Conductometric titration,Packing structure,Viscosity,Chitosan
更新于2025-09-10 09:29:36
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Synthesis, characterization, swelling-deswelling properties of Novel nanoparticle-hydrogel containing core chitosan and their cyclohexanone-crosslinked counterparts
摘要： Novel Chitosan-cyclohexanone Mannich based hydrogel nanoparticles (CCMb1-4) were prepare via the reaction of chitosan with different concentration of 2, 6-bis (piperidin-1-ylmethyl) cyclohexanone. 2HCl (1%, 5%, 10% and 15% wt/wt) at 70–80°C for 7 h. These hydrogels were subjected to equilibrium swelling studies at room temperature in solutions of pH 2, 4, 6 and 8. The (CCMb1-4) showed maximum percent swellability at pH = 2.0. Furthermore, the swelling of the (CCMb1-4) followed Fickian diffusion. This preliminary investigation of chitosan-based interpolymeric hydrogels showed that they may be exploited to expand the utilization of these systems in drug delivery applications.
关键词： Chitosan,mannish base,hydrogels,drug delivery,swellability
更新于2025-09-10 09:29:36
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Comparative study on the behaviour of Chitosan-Gelatin based Hydrogel and nanocomposite ion exchanger synthesized under microwave conditions towards photocatalytic removal of cationic dyes
摘要： The present work reports the comparison study of Chitosan-Gelatin based hydrogels with their nanocomposite ion exchangers synthesized under microwave conditions for the adsorption and photodegradation of the cationic dyes. In this report, the hydrogel based on Chitosan-Gelatin, more selective for anionic dyes is modified to nanocomposite ion exchanger by incorporating the zirconium (IV) selenophosphate1 to make it selective for cationic dyes. The nanocomposite was investigated with a tremendous hike in the degradation capacity (99% from 12%) of MB after being modified to nanocomposite ion exchanger. Adsorption process followed Langmuir adsorption (Qo = 10.46 mgg-1) and non linear PFO kinetic model with k1, qe (calculated), R2, RMSE = 0.011, 1.02 (mgg-1), 0.996, and 0.01709 respectively.
关键词： nonlinear PFO,ion exchanger,cationic dye,nanocomposite,Chitosan,Langmuir
更新于2025-09-10 09:29:36
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pH Variation as a Simple and Selective Pathway for Obtaining Nanoparticle or Nanocapsule Polysaccharides
摘要： The fabrication of polysaccharides to be nanoparticles or nanocapsules is quite specific due to various parameters and factors. The present work demonstrates a simple pathway to selectively prepare the ionic polysaccharide flakes to be nanoparticles or nanocapsules. The systematic studies on the model cases of cationic polysaccharide (i.e. chitosan) and anionic polysaccharide (i.e. alginate) confirm that pKa is the key point to tune the polysaccharides to be nanoparticles or nanocapsules. When the ionic polysaccharides were in an oil/water emulsion system, the pH close to pKa leads to the densely packed polysaccharide chains under the hydrogen bond networks, and as a result the crosslink occurs all through the chains to be nanoparticles. On the other hand, when pH was adjusted to the lower or higher than pKa depending on the types of ionic polysaccharide, the polysaccharide chains are under charge-charge repulsive force, resulting in the alignment of polysaccharide chains to be hollow nanospheres, and at that time the crosslink initiates the formation of nanocapsules. The present work, for the first time, clarifies that pH variation is the key to selectively prepare nanoparticles or nanocapsules, and this is important for delivery systems, coatings, sensors, etc.
关键词： pH-tunable morphology,chitosan,alginate,emulsion system,Polysaccharide
更新于2025-09-10 09:29:36
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Colorimetric detection of cysteine based on dispersion - aggregation of chitosan stabilized gold nanoparticles
摘要： A simple and selective colorimetric method of detection of cysteine using chitosan stabilized gold nanoparticles has been developed. L-cysteine is a sulfur containing amino acid. Cysteine binds with the gold nanoparticles through sulfur group and induces aggregation of the nanoparticles which leads to an apparently visible color change from pale red to blue. A good linearity was observed from 0.1 to 30 μM (R=0.9958) cysteine and the limit of detection was found to be 0.1 μM. The gold nanoparticles showed a high selectivity towards the detection of cysteine even in the presence of 10,000 fold higher concentration of common interferences such as glutathione, methionine and homocysteine. A plausible mechanism for the selective detection of cysteine in presence of interferences based on a dispersion-aggregation mechanism has been proposed.
关键词： Sensitivity,Chitosan,Gold nanoparticles,Colorimetric sensor,Cysteine
更新于2025-09-09 09:28:46
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INVESTIGATION OF rGO AND CHITOSAN EFFECTS ON OPTICAL AND ELECTRICAL PROPERTIES OF THE CONDUCTIVE POLYMERS FOR ADVANCED APPLICATIONS
摘要： A simple and fast method for preparing chitosan (CH)/conducting polymer (CP) composite film with and without reduced graphene oxide (rGO) was realized to investigate the effect of rGO on an optoelectrochemical system. For this purpose, firstly rGO was successfully dispersed in the acidic aqueous solution of CH by ultrasonic agitation. One by one CH and CH/rGO blend deposited on an indium tin-oxide (ITO) coated glass electrode by drop-casting method. After that, N1,N4-bis(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)terephthalamide (m(BT)) electroactive monomer was deposited onto CH and CH/rGO modified ITO electrode surfaces via electrochemical polymerization. Electrochemical and optical properties of the composite structures were investigated by cyclic voltammetry (CV) technique and UV-vis spectroscopy. The surface characterizations of nanocomposites have been performed by scanning electron microscopy. It was observed that, chemical functionalities of CH, rGO and p(BT) provide excellent compatibility. Therefore, the CH/rGO/p(BT) electroactive nanocomposite has better conductivity, stability, charge density, electrochromic switching kinetics and electrochemical properties than the CH/p(BT) and p(BT)/rGO composites. This is due to more efficient synergistic effect between CH, rGO and p(BT) which provide larger active surface area and ease ion transport. This method for producing composite films with novel optical, electrical and stability properties has been gaining a new perspective in the material world, which enables smart and advanced material design in various practical applications especially for designing molecular detection systems.
关键词： conducting polymer,rGO,spectroelectrochemistry,chitosan
更新于2025-09-09 09:28:46
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A blue fluorescent labeling technique utilizing micro- and nanoparticles for tracking in LIVE/DEAD® stained pathogenic biofilms of Staphylococcus aureus and Burkholderia cepacia
摘要： Strategies that target and treat biofilms are widely applied to bacterial cultures using popular live/dead staining techniques with mostly red or green fluorescent markers (eg, with SYTO? 9, propidium iodide, fluorescein). Therefore, visualizing drugs or micro- and nanoparticulate delivery systems to analyze their distribution and effects in biofilms requires a third fluorescent dye that does not interfere with the properties of the live/dead markers. The present study establishes and evaluates a model for tracking polymeric particles in fluorescently stained biological material. To this end, poly(d,l-lactide-co-glycolide) (PLGA)-based micro- and nanoparticles were used as well-established model systems, which, because of their favorable safety profiles, are expected to play important future roles with regard to drug delivery via inhalation. PLGA was covalently and stably labeled with 7-amino-4-methyl-3-coumarinylacetic acid (AMCA), after which blue fluorescent poly(ethylene glycol)-block-PLGA (PEG-PLGA) particles were prepared using a mixture of fluorescent AMCA-PLGA and PEG-PLGA. Because chitosan is known to reduce negative surface charge, blue fluorescent PEG-PLGA-particles with chitosan were also prepared. These micro- and nanoparticles were physicochemically characterized and could be clearly distinguished from live/dead stained bacteria in biofilms using confocal laser scanning microscopy.
关键词： 7-amino-4-methyl-3-coumarinylacetic acid,cystic fibrosis,PEG,PLGA,chitosan,hydrodynamic diameter,confocal laser scanning microscopy
更新于2025-09-09 09:28:46
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Hydroxypropyl Methacrylate Interaction and Chitosan Coating for Enhanced UV Detection Sensitivity of Colloidal Nanoparticles in Capillary Electrophoresis Analysis
摘要： The binding interactions between silica (SiO2), titania (TiO2) or polymeric nanoparticles with hydroxypropyl methacrylate (HPMA) were investigated for enhancing the ultraviolet (UV) detection sensitivity of these nanoparticles in capillary electrophoresis (CE) analysis. HPMA interacted with colloidal SiO2 nanoparticles, producing a larger CE-UV peak at a slightly shorter migration time. An increase in particle size with HPMA binding was validated using dynamic light scattering. The interaction was selective as HPMA did not interact with TiO2 nanoparticles in aqueous suspension. Chitosan coating of SiO2 or TiO2 nanoparticles produced significantly larger hydrodynamic diameters to further enhance the sensitivity of their UV detection. The analytical technique, which involves coating SiO2 nanoparticles with chitosan first and binding with HPMA next, is novel. It has allowed us to achieve a significant enhancement of 50 folds in detection sensitivity.
关键词： Titania,Colloid,Nanoparticles,Capillary electrophoresis,Chitosan,Hydroxypropyl methacrylate,Silica,Polymer,Dynamic light scattering
更新于2025-09-09 09:28:46