Aims: This study was designed to evaluate the effectiveness of the synthesised carvacrol loaded chitosan nanoparticles (CLCNPs) on the growing and pre-formed biofilms of Listeria monocytogenes isolated from slaughterhouses. Methodology and results: The swab samples were collected from knives, hocks and cutting tables representing slaughterhouses meat contact surfaces (MCS), while those samples from walls and floors represent slaughterhouses meat non-contact surfaces (MNCS). The bacteriological analysis revealed the existence of L. monocytogenes with a prevalence rate of 3.3, 10 and 6.7% for knives, hocks and cutting tables, respectively and 2.2 and 6.6% for walls and floors, respectively. The isolates L. monocytogenes were assayed for biofilm production by the crystal violet binding assay method. Among the 10 L. monocytogenes isolates, 10%, 50% and 30% of the isolates were found to be strong, moderate and weak biofilm producers, respectively. The activities of carvacrol, chitosan nanoparticles (NPs) and CLCNPs against the only strong biofilm producer strain of L. monocytogenes were tested by microtiter plate assay. The minimum inhibitory concentrations (MIC) values were 3.75 mg/mL for CAR, 5 mg/mL for chitosan NPs and 0.62 mg/mL for CLCNPs. CLCNPs inhibit the produced biofilm by 35.79, 73.37 and 77.76%, when 0.5 MIC, 1 MIC and 2 MIC were used, respectively. Furthermore, the pre-formed L. monocytogenes biofilms were significantly reduced from 1.01 (control) OD570 to 0.40 and 0.29 OD570 by applying 2 MIC and 4 MIC doses, respectively. Conclusion, significance and impact of study The data generated is promising to develop bio-green disinfectants to inhibit biofilm formation by L. monocytogenes in the food processing environment and control its adverse effects for consumers.
Chitosan--chemistry ; Listeria monocytogenes ; Nanoparticles

Microcrystalline cellulose and chitosan were applied to prepare ginkgolides component solid dispersions micro pill drug release unit and study the dissolution of GKS. Microcrystalline cellulose, chitosan as composite carrier, solvent method was used to prepare ginkgolides component solid dispersions. Differential scanning calorimetry was used to Characterization of ginkgolides component solid dispersions. Ginkgolides component solid dispersions as principle agent were prepared for micro-pellet. Comparison of different types, different doses of the adhesive, drug-polymer interactions, and disintegrating agent for the preparation of ginkgolides components of micro-pellet drug release unit, the optimum preparation ginkgolides components of micro-pellet drug release unit was screened by orthogonal design experiment. Preparation of ginkgolides components solid dispersions with microcrystalline cellulose and chitosan at ratio 1: 3. Drug cumulative dissolution was more than 80% in 60 min. Solid dispersion-micro-pellet drug release unit can significantly improve the dissolution of ginkgolides components, it has practical application value.
Cellulose ; chemistry ; Chitosan ; chemistry ; Drug Compounding ; methods ; Ginkgolides ; chemistry

Chitosan has natural abundance, unique bioactivity and attractive physicochemical properties. Recent years, the synthesis of chitosan-based metal nanomaterials has attracted increasing attention. The synthesis of metal nanoparticles utilizing biomolecular or organism offers a mild medium, and thus a greater degree of control over the nanoparticles produced, along with higher reproducibility. In particular, preparation of metal nanoparticles based on biomolecular or organism has its unique facility in integrating "minimum feature sizes" into labile biological components to an excellent synergy and bifunctional effect and consequently a more broad application. Herein, we review the new development of chitosan, chitosan-based synthesis of metal nanomaterials, and their application.
Catalysis ; Chitosan ; chemistry ; Metal Nanoparticles ; chemistry ; Oxidation-Reduction

OBJECTIVE: To characterize the silver in chitosan antibacterial gel, and to establish a method for the determination of silver content in samples. METHODS: The silver in the samples was analysed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and single particle inductively coupled plasma mass spectrometry (SP-ICP-MS). Microwave digestion was adopted to digest the chitosan antibacterial gel, and then the content of silver was determined by flame atomic absorption spectrometry. RESULTS: The analysises showed that the particle size of silver in chitosan antibacterial gel was about 150~ 200 nm. The silver showed good linearity in the concentration range of 25~250 μg/L (y=0.000 35x+0.001 7, r=0.999 9). The recovery rate (n=9) was 98.5%. CONCLUSIONS SEM, EDS and SP-ICP-MS can be used for the characterization of silver particles in chitosan antibacterial gel. Microwave digestion-flame atomic absorption spectrophotometry method is simple, practicable, high precision and high quantitative accuracy, which is suitable for the quantitative analysis of silver in chitosan antibacterial gel.
Anti-Bacterial Agents/pharmacology* ; Chitosan/chemistry* ; Microwaves ; Particle Size ; Silver

OBJECTIVETo study the effect of quaternary ammonium salt of chitosan (HACC) in purifying aqueous extracts of Zhisou Dingchuan oral solution.

METHODModified quaternary ammonium salt of chitosan was used to flocculate aqueous extracts of Zhisou dingchuan oral solution, with turbidity degree and the retention rate of ephedrine and glycyrrhizin as indicators, to detect the influences of flocculant dosage, suspension temperature, mixing speed and time on flocculation effect. The optimum process conditions were found through orthogonal experimental design.

RESULTThe optimum process conditions: the flocculation temperature 30 degrees C, HACC's dosage 0.4 g x L(-1), the fast mixing speed 500 r x min(-1) and its time 1 min, the slow mixing speed 50 r x min(-1) and it time 2.4 10 min. Under the conditions, the retention rate of ephedrine was 97.6%, the turbidity degree was 1.1 NTU and 2.8 NTU after 30 days.

CONCLUSIONHACC can be used to purify aqueous extracts of Zhisou Dingchuan oral solution.

Chitosan ; chemistry ; Drugs, Chinese Herbal ; chemistry ; Flocculation ; Quaternary Ammonium Compounds ; chemistry ; Solutions ; chemistry

Activity losing during the covalent immobilization of enzyme is a serious problem. Here we studied organic phase immobilization by using glucose oxidase (GOD) as a model. After lyophilized at optimum pH, GOD is covalently immobilized onto glutaraldhyde-activated chitosan microsphere carrier under the condition of water, 1, 4-dioxane, ether and ethanol separately. The special activities, enzyme characterization and kinetic parameters are determined. Results show that all of the organic phase immobilized GODs have higher special activities and larger K(cat) than that of aqueous phase. Under the conditions of 0.1% of glutaraldehyde, 1.6% moisture content with 80 mg of GOD added to per gram of carrier, 2.9-fold of the special activity and 3-fold of the effective activity recovery ratio were obtained, and 3-fold of the residue activity was demonstrated after 7 runs when compares 1, 4-dioxane phase immobilized GOD with water phase immobilized one. In addition, kinetic study shows that 1,4-dioxane immobilized GOD (Km(app) = 5.63 mmol/L, V(max) = 1.70 micromol/(min x mg GOD), K(cat) = 0.304 s(-1) was superior to water immobilized GOD (Km(app) = 7.33 mmol/L, V(max) = 1.02 micromol/(min x mg GOD), K(cat) = 0.221 s(-1)). All above indicated GOD immobilized in proper organic media presented a better activity with improved catalytic performance. Organic phase immobilization might be one of the ways to overcome the conformational denature of enzyme protein during covalent modification.
Chitosan ; chemistry ; Dioxanes ; chemistry ; Enzymes, Immobilized ; chemistry ; Freeze Drying ; Glucose Oxidase ; chemistry ; Kinetics ; Microspheres

Comparing to Chitosan, Chitosan-oligosaccharides have several special functions, such as water-soluble, antitumor activity, immunostimulating effects, and antimicrobial activity. The chitosan-oligosaccharide, the molecular weight of which was about 5000, was used as research model. According to the agarose gel electrophoresis and UV spectrophotometer it was proved that electrostatic interaction was playing a very important role in the formation process of chitosan-oligosaccharide/DNA complex. The potential of adsorbing DNA on chitosan-oligosaccharide was analyzed by gel electrophoresis and UV spectrophotometer, and it was indicated that chitosan-oligosaccharide can improve the storage and structure stability of DNA. To check its protection ability to DNA by DNase I digestive experiment, the result showed that chitosan-oligosaccharide could load with plasmid effectively and protect DNA from being digested by DNase I. It was proved that chitosan-oligosacchide was safe and effective for gene delivery and will have a very good future in the field of gene therapy.
Chitosan ; chemistry ; DNA ; chemistry ; Gene Transfer Techniques ; Genetic Vectors ; Nanoparticles ; chemistry ; Oligosaccharides ; chemistry

With low molecular weight chitosan and poloxamer 188 as the joint carriers, ginsenoside Rg3 solid dispersions were prepared by using the solvent evaporation method for an in vitro dissolution test. Subsequently, differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and X-ray diffraction (X-RD) were adopted for a phase analysis. The results showed that the 60 min in vitro cumulative dissolution rate of ginsenoside Rg3 solid dispersions prepared with low molecular weight chitosan and poloxamer 188 at the ratio of 2:1 exceeded 90%, and the drug was dispersed in carriers in an amorphous state. Therefore, ginsenoside Rg3 solid dispersions prepared with low molecular weight chitosan and poloxamer 188 could help significantly improve the drug dissolution, with a practical application value.
Chitosan ; chemistry ; Drug Compounding ; methods ; Ginsenosides ; chemistry ; Molecular Weight ; Poloxamer ; chemistry ; Solvents ; chemistry

Pulpitis, periodontitis, jaw bone defect, and temporomandibular joint damage are common oral and maxillofacial diseases in clinic, but traditional treatments are unable to restore the structure and function of the injured tissues. Due to their good biocompatibility, biodegradability, antioxidant effect, anti-inflammatory activity, and broad-spectrum antimicrobial property, chitosan-based hydrogels have shown broad applicable prospects in the field of oral tissue engineering. Quaternization, carboxymethylation, and sulfonation are common chemical modification strategies to improve the physicochemical properties and biological functions of chitosan-based hydrogels, while the construction of hydrogel composite systems via carrying porous microspheres or nanoparticles can achieve local sequential delivery of diverse drugs or bioactive factors, laying a solid foundation for the well-organized regeneration of defective tissues. Chemical cross-linking is commonly employed to fabricate irreversible permanent chitosan gels, and physical cross-linking enables the formation of reversible gel networks. Representing suitable scaffold biomaterials, several chitosan-based hydrogels transplanted with stem cells, growth factors or exosomes have been used in an attempt to regenerate oral soft and hard tissues. Currently, remarkable advances have been made in promoting the regeneration of pulp-dentin complex, cementum-periodontium-alveolar bone complex, jaw bone, and cartilage. However, the clinical translation of chitosan-based hydrogels still encounters multiple challenges. In future, more in vivo clinical exploration under the conditions of oral complex microenvironments should be performed, and the combined application of chitosan-based hydrogels and a variety of bioactive factors, biomaterials, and state-of-the-art biotechnologies can be pursued in order to realize multifaceted complete regeneration of oral tissue.
Chitosan/chemistry* ; Tissue Engineering ; Hydrogels/chemistry* ; Biocompatible Materials/chemistry* ; Cartilage ; Tissue Scaffolds/chemistry*

OBJECTIVETo prepare kappa-carrageenan-chitosan polyelectrolyte gel pellets and detect the effects of formulation and preparation factors on in vitro drug release from the pellets.

METHODThe K-carrageenan-chitosan polyelectrolyte gel pellets with baicalin as model drug were prepared by ionotropic gelation technique. The ratio of kappa-carrageenan/chitosan in pellets was determined with the composite of K-carrageenan and chitosan. The effects of the concentration of K-carrageenan, the ratio of drug/kappa-carrageenan, the concentration of gelling solution, gelling time and drying method on the release of pellets were determined by in vitro drug release.

RESULTThe mass ratio of K-carrageenan/chitosan in pellets was 6: 4. Release of the pellets in 0.1 mol x L(-1) HCl was about 10% for 2 hours and fast in PBS, indicating a typical sustained release property. The pellets released less with the increase in the concentration of K-carrageenan, the ratio of drug/kappa-carrageenan and the concentration of KCl. They also released less with the increase in gelling time, but showed little effect until 1 hour. The release of the pellets prepared by the freeze-drying method was much faster than those by vacuum drying and atmospheric drying methods which had little influence on drug release.

CONCLUSIONThe K-carrageenan-chitosan polyelectrolyte gel pellets had sustained release property. Their drug release rate could be regulated with different formulation and preparation factors.

Carrageenan ; chemistry ; Chemistry, Pharmaceutical ; Chitosan ; chemistry ; Desiccation ; Drug Carriers ; chemistry ; Electrolytes ; chemistry ; Gels ; Microspheres ; Potassium Chloride ; chemistry ; Time Factors