Research Progress of Carboxymethyl Chitosan-Based Haemostatic Materials and Their Haemostatic Mechanism --Review / 中国实验血液学杂志

Effective haemostatic materials can quickly control bleeding and achieve the purpose of saving patients' lives. In recent years, chitosan-based haemostatic materials have shown good haemostatic effects, but their application is limited because chitosan is almost insoluble in water. Carboxymethyl chitosan-based haemostatic materials can promote hemostasis by activating red blood cells and aggregating platelets. In addition, carboxymethyl chitosan can bind with Ca2+ to activate platelets and coagulation factors, and start endogenous coagulation pathways, which can adsorb fibrinogen in plasma to promote haemostasis. In this paper, the latest research progress of carboxymethyl chitosan-based haemostatic materials and their haemostatic mechanism were reviewed, in order to further strengthen the understanding of the haemostatic mechanism of carboxymethyl chitosan-based haemostatic materials, and provide new idea for the research and clinical application of carboxymethyl chitosan-based haemostatic materials.

A Novel Lyophilized PRP-Loaded Gel Based on Chitosan and PEG with Hemostatic and Antibacterial Properties / 中国实验血液学杂志

OBJECTIVE@#A dynamic gel loaded with lyophilized platelet-rich plasma-chitosan/difunctionalized polyethylene glycol (LPRP-CP) was prepared to investigate its hemostatic antibacterial and promoting wound healing of scald wounds through in vitro and in vivo experiments.@*METHODS@#In this study, normal gauze/blank tablet (Ctrl), LPRP-CP, Chitosan HUCHUANG Powder(Chito P)and ChitoGauze XP PRO group (Chito G group) were set. The hemostatic effect and promoting healing effect of the four groups of materials were evaluated by establishing rabbit ear artery hemorrhage model and superficial Ⅱ° scalded model of skin on the back. The hemostatic time and bleeding amount were calculated and the gross and histological results of scald healing were observed. The antibacterial effect of the four groups of materials was evaluated by antibacterial test in vitro.@*RESULTS@#In the rabbit ear arterial hemorrhage model, the hemostasis of all materials was successful. The hemostatic time of Ctrl, Chito P, LPRP-CP and Chito G groups was 213.33±38.30, 118.33±24.01, 115.00±8.37 and 111.67±11.69 s, respectively. The blood loss was 1233.83±992.27, 346.67±176.00, 193.33±121.47 and 147.50±80.66 mg, respectively. Compared with Ctrl, the hemostasis time of LPRP-CP, Chito P and Chito G group was significantly shorter (P<0.001), and the amount of blood loss of LPRP-CP and Chito G group was decreased (P<0.05). Compared with LPRP-CP, there were no significant differences in hemostatic time and blood loss between Chito P and Chito G group (P>0.05). In the model of superficial Ⅱ° scalded on the back of rabbit, the wound healing rate of LPRP-CP was faster than that of the other three groups at the same time, and the healing effect was perfect. In the antibacterial test in vitro, only LPRP-CP had better anti-S. aureus effect, and all groups had no anti-E. coli effect.@*CONCLUSION@#LPRP-CP is an excellent hemostatic material for superficial wounds, and has certain antibacterial and wound healing effects, which has a wide academic value and research prospects.

Preparation and intestinal absorption of Panax notoginseng saponins chitosan nanoparticles / 中国中药杂志

In this experiment, Panax notoginseng saponins chitosan nanoparticles(PNS-NPs) were prepared by self-assembly and their appearance, particle size, encapsulation efficiency, drug loading, polydispersity index(PDI), Zeta potential, and microstructure were characterized. The prepared PNS-NPs were intact in structure, with an average particle size of(209±0.258) nm, encapsulation efficiency of 42.34%±0.28%, a drug loading of 37.63%±0.85%, and a Zeta potential of(39.8±3.122) mV. The intestinal absorption of PNS-NPs in rats was further studied. The established HPLC method of PNS was employed to investigate the effects of pH, perfusion rate, and different drugs(PNS raw materials, Xuesaitong Capsules, and PNS-NPs). The absorption rate constant(K_a) and apparent permeability coefficient(P_(app)) in the duodenum, jejunum, ileum, and colon were calculated and analyzed. As illustrated by the results, the intestinal absorption of PNS-NPs was increased in the perfusion solution at pH 6.8(P<0.05), and perfusion rate had no significant effect on the K_a and P_(app) of PNS-NPs. The intestinal absorption of PNS-NPs was significantly different from that of PNS raw materials and Xuesaitong Capsules(P<0.05), and the intestinal absorption of PNS-NPs was significantly improved.

Research and Application Progress of Chitosan-based Hemostatic Materials---Review / 中国实验血液学杂志

Whether in war or peace, timely, effective and accurate hemostasis is an important measure to improve the survival rate and cure rate of the wounded. All the countries in the world are actively developing different types of hemostatic materials so as to reduce the amount of bleeding in an emergency and create favorable conditions for subsequent transport and treatment. At present, the commercialized hemostatic materials are mainly divided into natural biological, synthetic biological, mineral and coagulation components, but all these materials have their own limitations. In this article, the characteristics of chitosan and its derivatives are reviewed as the representatives of the natural organic macromolecular polysaccharide hemostasis materials. Their molecular structures, biomedical properties, domestic and foreign research and application progress as well as comparison with applications of other hemostatic materials are involved. The further research is prospected for optimization and innovation to develop composite chitosan hemostatic materials with the function of hemostasis, antibiosis, pain relief and promoting wound healing.

Preparation and characterization of a novel antimicrobial film dressing for wound healing application

Antibacterial activity and good mechanical properties are some of the characteristics required for an appropriate film dressing. A novel polymer blend was developed for wound healing application. Twenty-four formulations using the polymers chitosan, poly(vinyl alcohol) and/or ɛ-Polylysine and the plasticizer glycerol were designed using factorial design and then the films were prepared by the casting/solvent evaporation method. Seventeen films were obtained among the twenty-four proposed formulations that were characterized by Field Emission Scanning Electron Microscopy (FE-SEM) and Fourier Transform Infrared Spectroscopy (FTIR). Mechanical properties, such as tensile strength (σ), elongation at break (ɛ) and Young's modulus (Y) as well as antibacterial properties were determined. The best candidate was then further analyzed with regard to porosity, Water Vapor Transmission Rate (WVTR), swelling and cytotoxicity experiments. The results showed a film with semi-occlusive characteristics, good mechanical properties and no toxic. Incorporation of ɛ-Polylysine increased antibacterial activity against gram-negative (Escherichia coli) and gram-positive (Staphylococcus aureus) bacteria

Effect of Chitosan Addition in Whey-based Biodegradable Films

Abstract Whey, a by-product of dairy industry, is a feedstock widely employed in the production of biodegradable films. However, these films present some limitations when considering the performance of synthetic polymers, especially biological transformation by decomposition. This work aimed to evaluate the effects of chitosan addition to whey-based films to improve films physical-chemical properties and resistance to microbial degradation. The results showed that there was an interaction effect between the chitosan concentration and the storage time for the physical-chemical properties of elongation at break and opacity. There was statistical difference among the formulations; however, for the moisture content and film thickness, there was no interaction effect between the formulation and the storage time. The films with 1.5 and 3.0 wt.% chitosan presented a yellowish hue, characteristic of the polysaccharide; this could also be detected by SEM analysis. The films presented an excellent biodegradability, being decomposed in about 8 days. Considering all chitosan contents tested had similar performances, the chitosan content of 0.15 wt.% was the one with the better cost-benefit relation.

Efeito do laser de baixa intensidade na atividade biológica de células-tronco do ligamento periodontal humano cultivadas sobre arcabouços de quitosana / Effect of low-intensity laser on the biological activity of human periodontal ligament stem cells cultured on chitosan scaffolds

O laser de baixa intensidade (LBI) é capaz de estimular a proliferação de diferentes tipos celulares, porém pouco se sabe sobre sua eficácia na proliferação de células cultivadas na superfície dos biomateriais. O objetivo deste estudo foi avaliar a influência do LBI na proliferação e viabilidade de células-tronco do ligamento periodontal humano (PDLSCs) cultivadas em arcabouços de quitosana. A quitosana foi submetida a testes para identificação do teor real de massa e grau de desacetilação. Membranas de quitosana foram preparadas pela técnica de evaporação de solvente e submetidas a caracterização de morfologia e de superfície. PDLSCs previamente isoladas e caracterizadas foram cultivadas sobre quatro superfícies: (P) plástico da placa de cultivo, não irradiado, como controle positivo de crescimento celular; (Q) quitosana, não irradiado; (L1) quitosana, irradiado com dose de 1 J/cm²; e (L4) quitosana, irradiado com 4 J/cm². As irradiações foram realizadas com laser diodo InGaAlP, com comprimento de onda de 660 nm, potência de 30 Mw, diâmetro da ponta de 0.01cm² e modo de ação contínuo, em dose única. Os dados mostraram que a quitosana apresentou um teor real de massa de 88,08% e grau de desacetilação de 91,37±3,77%. A análise das membranas por MEV mostrou superfície uniforme e homogênea, com espessura média de 68,71 µm. A análise por microscopia de força atômica revelou uma rugosidade média de 285 nm. O peso das membranas variou de 0,03 a 0,04 g, indicando a sua uniformidade, e o pH de superfície exibiu média de 6,9±0,25, valor próximo ao pH da saliva. A viabilidade e a proliferação celular foram avaliadas através dos ensaios de Alamar Blue, Live/Dead, Annexin V/PI e Ki67, além da análise do ciclo celular, e a morfologia celular foi avaliada por microscopia eletrônica de varredura (MEV). O ensaio do Alamar Blue mostrou diferenças significativas na atividade mitocondrial entre os grupos nos intervalos de 24 h (L1>Q, p= 0,0118) e em 48 h (L1>Q, p= 0,0022; L4>Q, p=0,0002; L4>L1, p= 0,0022). O ensaio Live/Dead mostrou maior densidade de células vivas nos grupos irradiados (L1 e L4) em relação ao grupo sem irradiação (Q), o que foi comprovado pelo ensaio da Annexin V/PI, que mostrou um maior percentual de células viáveis em L4 (89,5%) e L1 (87,0%) em comparação com Q (78,4%) em 72 h. A imunoexpressão da proteína Ki67 foi maior em L4 e L1 e estes dois grupos apresentaram também um maior percentual de células nas fases proliferativas do ciclo celular (S e G2/M). A análise por MEV mostrou no grupo Q células com morfologia mais arredondada e com poucas projeções, além de debris celulares, enquanto nos grupos irradiados as células exibiram um arranjo mais plano, com projeções mais distribuídas e pontos de adesão focal, especialmente em L4. Em conjunto, os resultados do presente trabalho permitem concluir que a laserterapia nos padrões estudados, especialmente na dose de 4 J/cm², influencia positivamente a viabilidade e a proliferação de PDLSCs em membranas de quitosana, permitindo assim que as células superem eventuais efeitos adversos do microambiente do arcabouço (AU).

Low-level laser irradiation (LLLI) is able to stimulate the proliferation of various cell types, but little is known about its effectiveness on the proliferation of cells cultured on biomaterial surfaces. The aim of this study was to evaluate the influence of LLLI on the proliferation and viability of human periodontal ligament stem cells (PDLSCs) cultured on chitosan scaffolds. Chitosan was submitted to tests to identify the real mass content and degree of deacetylation. Chitosan membranes were prepared by solvent evaporation technique and submitted to morphology and surface characterization. PDLSCs previously isolated and characterized were grown on the surfaces of four groups: (P) culture plate plastic, non-irradiated, as a positive control of cell growth; (C) chitosan, non-irradiated; (L1) chitosan irradiated with a dose of 1 J/cm²; and (L4) chitosan, irradiated with 4 J/cm². The irradiations were performed with InGaAlP diode laser with wavelength of 660 nm, power 30 mW, tip diameter of 0.01cm², and continuous action mode in a single dose. Cell viability and proliferation were evaluated by Alamar Blue, Live/Dead, Annexin V/PI and Ki67 assays, as well as cell cycle analysis, whereas cell morphology was evaluated by MEV. The data showed that the chitosan presented a real mass content of 88.08% and degree of deacetylation of 91.37 ± 3.77%. SEM analysis showed membranes with uniform and homogeneous surface, with a mean thickness of 68.71 µm. Analysis by AFM revealed roughness around 285 nm. The weight of the membranes ranged from 0.03 to 0.04 g, indicating their uniformity, and the surface pH exhibited a mean of 6.9 ± 0.25, a value close to the pH of the saliva. The Alamar Blue assay showed significant differences in mitochondrial activity between groups at 24 h (L1> C, p = 0.0118) and at 48 h (L1> C, p = 0.0022; L4> C, p = 0.0002; L4>L1, p = 0.0022). The Live/Dead assay showed higher density of live cells in irradiated groups (L1 and L4) compared to the group without irradiation (C), which was confirmed by assay of Annexin V/PI, which showed a greater percentage of viable cells in L4 (89.5%) and L1 (87.0%) compared to C (78.4%) at 72 h. The Ki67 immunoexpression was higher in L4 and L1 and these two groups also showed a higher percentage of cells in the proliferative phases of the cell cycle (S and G2/M). The SEM analysis showed in group C cells with more rounded morphology and with few projections, as well as cell debris, whereas in the irradiated groups the cells exhibited a more flat arrangement, more distributed projections and focal adhesion points, especially in L4. Taken together, the results of the present study shown that laser therapy in the studied patterns, especially at the dose of 4 J/cm², has a positive effect on viability and proliferation of PDLSCs on chitosan membranes, thereby allowing the cells to overcome any adverse effects of the scaffold microenvironment (AU).

Effect of iodonium salt and chitosan on the physical and antibacterial properties of experimental infiltrants

Abstract Resinous infiltrants are indicated in the treatment of incipient carious lesions, and further development of these materials may contribute to greater control of these lesions. The aim of this study was to analyze the physical and antibacterial properties of experimental infiltrants containing iodonium salt and chitosan. Nine experimental infiltrants were formulated by varying the concentration of the diphenyliodonium salt (DPI) at 0, 0.5 and 1 mol%; and chitosan at 0, 0.12 and 0.25 g%. The infiltrants contained the monomeric base of triethylene glycol dimethacrylate and bisphenol-A dimethacrylate ethoxylate in a 75 and 25% proportion by weight, respectively; 0.5 mol% camphorquinone and 1 mol% ethyl 4-dimethylaminobenzoate. The degree of conversion was evaluated using Fourier transformer infrared spectroscopy, and the flexural strength and elastic modulus using the three-point bending test. Sorption and solubility in water, and antibacterial analysis (minimum inhibitory concentration and minimum bactericidal concentration) were also analyzed. Data was analyzed statistically by two-way ANOVA and Tukey's test (p<0.05), with the exception of the antibacterial test, which was evaluated by visual inspection. In general, the infiltrant group containing 0.5% DPI and 0.12% chitosan showed high values of degree of conversion, higher values of elastic modulus and flexural strength, and lower sorption values in relation to the other groups. Antibacterial activity was observed in all the groups with DPI, regardless of the concentration of chitosan. The addition of DPI and chitosan to experimental infiltrants represents a valid option for producing infiltrants with desirable physical and antibacterial characteristics.

The efficacy of sustained-release chitosan microspheres containing recombinant human parathyroid hormone on MRONJ

Abstract Treatment of patients with bisphosphonate usage is a significant concern for oral surgeons because it interferes with jaw bone turnover and regeneration. In case of adverse effects manifesting related to bisphosphonate use, oral surgeons are usually treating and keep the patient's symptoms under control. In this study, we aimed to investigate a new treatment protocol for medication-related osteonecrosis of the jaw (MRONJ). This treatment protocol consisted of administering human parathyroid hormone (hPTH) loaded chitosan microspheres which were prepared by ionotropic gelation method or/and the prepared microspheres were suspended in a poloxamer gel. After in-vitro optimization studies, the efficacy of the chosen formulations was evaluated in-vivo studies. Zoledronic acid was administered daily to forty-eight adult female Sprague-Dawley rats, divided into four experimental groups, at a daily concentration of 0.11 mg/kg over three weeks to induce the MRONJ model. At the end of this period, maxillary left molar teeth were extracted. In the first group, the subjects received no treatment. In the negative control group, poloxamer hydrogel containing empty microspheres were immediately applied to the soft tissues surrounding the extraction socket. The treatment group-1 was treated with local injections of poloxamer hydrogel containing hPTH. The treatment group-2 was treated with a single local injection of poloxamer hydrogel containing hPTH-loaded chitosan microspheres. Both treatment groups received a total of 7 µg of hPTH at the end of the treatment protocol. Our study demonstrates successful attenuation of MRONJ through a local drug delivery system combined with hPTH, as opposed to previously attempted treatment strategies.

Lactoferrin, chitosan and Melaleuca alternifolia-natural products that show promise in candidiasis treatment

Abstract The evolution of microorganisms resistant to many medicines has become a major challenge for the scientific community around the world. Motivated by the gravity of such a situation, the World Health Organization released a report in 2014 with the aim of providing updated information on this critical scenario. Among the most worrying microorganisms, species from the genus Candida have exhibited a high rate of resistance to antifungal drugs. Therefore, the objective of this review is to show that the use of natural products (extracts or isolated biomolecules), along with conventional antifungal therapy, can be a very promising strategy to overcome microbial multiresistance. Some promising alternatives are essential oils of Melaleuca alternifolia (mainly composed of terpinen-4-ol, a type of monoterpene), lactoferrin (a peptide isolated from milk) and chitosan (a copolymer from chitin). Such products have great potential to increase antifungal therapy efficacy, mitigate side effects and provide a wide range of action in antifungal therapy.

The effects of chitosan oligosaccharides on OPG and RANKL expression in a rat osteoarthritis model

Abstract Purpose: To investigate the effect of chitosan oligosaccharides (COS) against osteoarthritis (OA) and preliminarily discuss the osteoprotegerin (OPG), receptor activator of NF-κB ligand (RANKL) and RANK expression in a rat OA model. Methods: Thirty-six 6-week-old Male SD rats were randomly divided into three groups: sham-operated group(CON), OA-induction group(OA), COS intervention group(n=12/group). At 4 weeks after the operation, COS (50 ul) intervention weekily for consecutive 5 weeks. The OA and CON groups received an injection of 50 ul physiological saline. At death, 11 weeks following surgery, cartilage was harvested and total RNA and protein were extracted. Both the morphological changes of the cartilage were observed and harvested the total RNA and protein. Meanwhile, the expression of OPG, RANKL and RANK in cartilage were determined. Results: The expression of OPG and RANKL were both enhanced in the cartilage of the OA model. Compared with the OA group, COS treatment improved the cartilage damage (both extent and grade). Furthermore, the COS group showed highly OPG and lower RANKL. Simultaneously, COS treatment upregulated the ratio of OPG/RANKL and downregulated the RANKL/RANK. Conclusion: Chitosan oligosaccharides may be used as a unique biological agent to prevent and treat osteoarthritis, and this effect is associated with modulation of the expression of osteoprotegerin and receptor activator of NF-κB ligand.

The anti-caries activity and toxicity of an experimental propolis-containing varnish

Abstract We investigated the anti-caries effects of an experimental propolis varnish in vivo, and further tested its toxicity against fibroblasts. Fifty-six SPF female Wistar rats were infected with Streptococcus mutans UA159 (SM) and allocated into four groups (n = 14/group): G1, propolis varnish (15%/PV); G2, chitosan varnish (CV/vehicle); G3, gold standard (GS/Duraphat®); and G4, untreated. The animals received a single varnish application on their molars and were submitted to a high cariogenic challenge (Diet-2000, 56% sucrose, and 5% sucrose-added water, ad libitum) for 4 weeks. Total cultivable microbiota and SM were counted, and smooth-surface and sulcal caries were scored. PV, CV and GS cytotoxic effects were tested against fibroblasts. The data were analyzed using ANOVA with the Tukey-Kramer test (p ≤ 0.05). Total microbiota and SM counts did not differ among the treatments (p = 0.78), or in relation to the untreated group (p = 0.52). PV reduced development of smooth-surface enamel caries compared with the untreated group (p = 0.0018), with no significant difference from GS (p = 0.92); however, the PV effects were no longer observed when the dentin was affected. Neither PV nor GS prevented enamel sulcal lesion onset, but GS significantly reduced the severity of dentinal sulcal lesions (p < 0.0001). No significant difference was observed in fibroblast viability between PV and GS (p < 0.0001). In conclusion, PV prevented smooth-surface enamel caries and showed low cell toxicity. Nevertheless, due to the high cariogenic challenge, its effects were not sustained throughout the experiment. Further studies are encouraged to establish a protocol to sustain the long-term anti-caries activity of PV in the oral cavity.

Design and preparation of a novel colon-targeted tablet of hydrocortisone

ABSTRACT The objective of this research was to design a new colon-targeted drug delivery system based on chitosan. The properties of the films were studied to obtain useful information about the possible applications of composite films. The composite films were used in a bilayer system to investigate their feasibility as coating materials. Tensile strength, swelling degree, solubility, biodegradation degree, Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), Scanning Electron Microscope (SEM) investigations showed that the composite film was formed when chitosan and gelatin were reacted jointly. The results showed that a 6:4 blend ratio was the optimal chitosan/gelatin blend ratio. In vitro drug release results indicated that the Eudragit- and chitosan/gelatin-bilayer coating system prevented drug release in simulated intestinal fluid (SIF) and simulated gastric fluid (SGF). However, the drug release from a bilayer-coated tablet in SCF increased over time, and the drug was almost completely released after 24h. Overall, colon-targeted drug delivery was achieved by using a chitosan/gelatin complex film and a multilayer coating system.

A stability-indicating HPLC-PDA method for the determination of ferulic acid in chitosan-coated poly(lactide-co-glycolide) nanoparticles

ABSTRACT The development and validation of a simple and efficient method for the quantification of ferulic acid in poly (D,L-lactide-co-glycolide) (PLGA) nanoparticles coated with chitosan (CS) by reverse phase high performance liquid chromatography coupled to photodiode array detection was described. For the chromatographic analysis, a reverse phase C-18 column was used, mobile phase consisting of acetonitrile and 0.5% acetic acid (37:63, v/v), isocratically eluted at a flow rate of 1 mL/min. Drug determination was performed at 320 nm. The method was validated in terms of the selectivity, linearity, precision, accuracy, robustness, limits of detection and quantification. The method was linear in the range of 10 to 100 µg/mL (r=0.999) and presented limit of detection and quantification of 102 ng/mL and 310 ng/mL, respectively. The method was precise (intra and inter-day) based on relative standard deviation values (less than 3.20%). The recovery was between 101.06 and 102.10%. Robustness was demonstrated considering change in mobile phase proportion. Specificity assay showed no interference from the components of nanoparticles or from the degradation products derived from acidic and oxidative conditions. The proposed method was suitable to be applied in determining the encapsulation efficiency of ferulic acid in PLGA-CS nanoparticles and can be employed as stability indicating one.

Effects of the protective, curative, and eradicative applications of chitosan against Penicillium expansum in apples

Abstract Apple is one of the most important temperate fruit to Brazil economy, and the use of synthetic chemicals has been the main method for reducing postharvest diseases, such as the blue mold, caused by Penicillium expansum. This work intends to evaluate the practical utilization of chitosan for blue mold control. For this purpose, fruits were treated in a preventive and curative way, immersing the fruits in chitosan solution (5 or 10 mg mL-1), or adding a single drop of this solution (10 mg mL-1) directly into the injuries. The eradicative effect of the polysaccharide was also evaluated in vitro and in vivo. Chitosan did not show a curative effect against the blue mold, and its eradicative effect was only evidenced on the higher concentration (10 mg mL-1). On the other hand, preventively, without the addition of adjuvants, chitosan reduced blue mold incidence in fruits by 24% and 93%, through the immersion or the single drop methods, respectively. Thus, it was found that, for long scale utilization, some improvements in the physico-chemical properties of the chitosan are needed, since it was only capable to prevent the infection by P. expansum when directly added on the fruit injury.

The use of chitosan in protecting wooden artifacts from damage by mold fungi

Background: Many buildings in Egypt e.g. museums, mosques and churches, do not possess controlled environments for minimizing the risks of damage of wooden artifacts due to the growth of fungi. Fungal damage usually appears as change in wood color, appearance of stains, and sometimes deformation of wooden surfaces. In this study we focused on the effect that some fungi exert on the properties of wooden artifacts and evaluated the effectiveness of different concentrations of chitosan on their protection against damage by mold fungi. Results: Samples were collected from different monuments and environments, and fungi growing on them were isolated and identified. The isolated Penicillium chrysogenum, Aspergillus flavus and /Aspergillus niger strains were used for the infestation of new pitch pine samples. The results revealed that the lightness of samples infected with any of the tested fungi decreased with increasing incubation times. XRD analysis showed that the crystallinity of incubated samples treated individually with the different concentrations of chitosan was lower than the crystallinity of infected samples. The crystallinity index measured by the first and the second method decreased after the first and second months but increased after the third and fourth months. This may due to the reducing of amorphous part by enzymes or acids produced by fungi in wooden samples. Conclusions: The growth of fungi on the treated wood samples decreased with increasing the concentration of chitosan. Hence, it was demonstrated that chitosan prevented fungal growth, and its use could be recommended for the protection of archeological wooden artifacts.

Antimicrobial activity of chitosan coatings and films against Listeria monocytogenes on black radish / Actividad antimicrobiana de coberturas y películas de quitosano contra Listeria monocytogenes en rábano negro

The antibacterial activity of chitosan coatings prepared with acetic or lactic acid, as well as of composite chitosan-gelatin films prepared with essential oils, was evaluated in fresh shredded black radish samples inoculated with Listeria monocytogenes ATCC 19115 and L. monocytogenes ATCC 19112 during seven days of storage at 4 °C. The chitosan coating prepared with acetic acid showed the most effective antibacterial activity. All tested formulations of chitosan films exhibited strong antimicrobial activity on the growth of L. monocytogenes on black radish, although a higher inhibition of pathogens was achieved at higher concentrations of chitosan. The antimicrobial effect of chitosan films was even more pronounced with the addition of essential oils. Chitosan-gelatin films with thyme essential oils showed the most effective antimicrobial activity. A reduction of 2.4 log10 CFU/g for L. monocytogenes ATCC 19115 and 2.1 log10 CFU/g for L. monocytogenes ATCC 19112 was achieved in the presence of 1% chitosan film containing 0.2% of thyme essential oil after 24 h of storage.

Se evaluó la actividad antimicrobiana de coberturas del quitosano y de películas compuestas de quitosano-gelatina en muestras frescas de rábano negro cortado inoculadas con las cepas de Listeria monocytogenes ATCC 19115 y ATCC 19112, almacenadas durante 7 días a 4 °C. Las primeras fueron preparadas con ácido acético o ácido láctico, las segundas con aceites esenciales. Las coberturas de quitosano preparadas con ácido acético mostraron la actividad antimicrobiana más eficaz. Todas las formulaciones de películas de quitosano exploradas mostraron una fuerte actividad antimicrobiana sobre el crecimiento de L. monocytogenes, aunque la mayor inhibición de estos patógenos se logró con las mayores concentraciones de quitosano. La actividad antimicrobiana de las películas de quitosano fue mayor con la adición de aceite esencial. Las películas de quitosano-gelatina con aceite esencial del tomillo fueron las que mostraron la actividad antimicrobiana más eficiente. A las 24 h de almacenamiento, la película con 1% de quitosano y 0,2% de aceite esencial de tomillo produjo una reducción de 2,4 log10 UFC/g en L. monocytogenes ATCC 19115, y de 2,1 log10 UFC/g en L. monocytogenes ATCC 19112.

Effects and molecular mechanism of chitosan-coated levodopa nanoliposomes on behavior of dyskinesia rats

BACKGROUND: Chitosan, the N-deacetylated derivative of chitin, is a cationic polyelectrolyte due to the presence of amino groups, one of the few occurring in nature. The use of chitosan in protein and drug delivery systems is being actively researched and reported in the literature RESULTS: In this study, we used chitosan-coated levodopa liposomes to investigate the behavioral character and the expression of phosphorylated extracellular signal-regulated kinase (ERK1/2), dopamine- and cAMP-regulated phos-phoprotein of 32 kDa (DARPP-32) and FosB/AFosB in striatum of rat model of levodopa-induced dyskinesia (LID). We found that scores of abnormal involuntary movement (AIM) decreased significantly in liposome group (P < 0.05), compared with levodopa group. Levels of phospho-ERK1/2, phospho-Thr34 DARPP-32 and FosB/AFosB in striatum decreased significantly in liposome group lesion side compared with levodopa group (P < 0.05). However, both of two groups above have significantly differences compared with the control group (P < 0.05). CONCLUSION: Chitosan-coated levodopa liposomes may be useful in reducing dyskinesias inducing for Parkinson disease. The mechanism might be involved the pathway of signaling molecular phospho-ERK1/2, phospho-Thr34 DARPP-32 and AFosB in striatum

Chitosan-collagen biomembrane embedded with calcium-aluminate enhances dentinogenic potential of pulp cells

Abstract The development of biomaterials capable of driving dental pulp stem cell differentiation into odontoblast-like cells able to secrete reparative dentin is the goal of current conservative dentistry. In the present investigation, a biomembrane (BM) composed of a chitosan/collagen matrix embedded with calcium-aluminate microparticles was tested. The BM was produced by mixing collagen gel with a chitosan solution (2:1), and then adding bioactive calcium-aluminate cement as the mineral phase. An inert material (polystyrene) was used as the negative control. Human dental pulp cells were seeded onto the surface of certain materials, and the cytocompatibility was evaluated by cell proliferation and cell morphology, assessed after 1, 7, 14 and 28 days in culture. The odontoblastic differentiation was evaluated by measuring alkaline phosphatase (ALP) activity, total protein production, gene expression of DMP-1/DSPP and mineralized nodule deposition. The pulp cells were able to attach onto the BM surface and spread, displaying a faster proliferative rate at initial periods than that of the control cells. The BM also acted on the cells to induce more intense ALP activity, protein production at 14 days, and higher gene expression of DSPP and DMP-1 at 28 days, leading to the deposition of about five times more mineralized matrix than the cells in the control group. Therefore, the experimental biomembrane induced the differentiation of pulp cells into odontoblast-like cells featuring a highly secretory phenotype. This innovative bioactive material can drive other protocols for dental pulp exposure treatment by inducing the regeneration of dentin tissue mediated by resident cells.

Efeito das nanopartículas de quitosana e da variação da concentração, temperatura e pH do hipoclorito de sódio sobre biofilmes orais formados in situ / Effect of chitosan nanoparticles and the temperature and pH variations of sodium hypochlorite on biofilms formed in situ

O objetivo deste estudo foi avaliar se a variação da temperatura e pH do hipoclorito de sódio (NaOCl), incrementa sua capacidade antibacteriana e de dissolução. Foi avaliado também, se as nanopartículas de Quitosana (CNPs) inibem o crescimento bacteriano e removem a lama dentinária. Foram utilizados 260 blocos de dentina bovina infetados intra-oralmente. As soluções experimentais foram NaOCl a 1% e 2.5%, a temperatura ambiente e 37oC e acidificado a pH 5 e 7. Os tempos de exposição foram 5 e 20 min. Os espécimes foram analisados pré (controle) e pósirrigação. Após esta análise, as amostras foram incubadas em BHI por 24 horas e analisadas novamente quanto a reativação bacteriana. Estes procedimentos foram realizados em duplicado para poder determinar a porcentagem de limpeza dentinária. Para analisar o efeito quelante das CNPs sobre a dentina infetada in situ, as amostras receberam uma irrigação final com CNPs em solução e analisadas imediatamente ou infetadas intra-oralmente para avaliar o efeito antibacteriano. O NaOCl apresentou poder antibacteriano e foi capaz de dissolver significativamente o biofilme sem importar sua temperatura. O NaOCl em pHs ácidos apresentaram alto poder antibacteriano, contudo seu poder de dissolução decresceu. As CNPs foram capazes de significativamente remover a lama dentinária e interferir com o crescimento bacteriano sobre dentina. Portanto, a temperatura do NaOCl não é relevante quando é testada sobre biofilmes multi-espécies. O poder antibacteriano do NaOCl foi inversamente proporcional a seu pH, enquanto que a sua capacidade de dissolução foi diretamente proporcional. As CNPs podem ser uma alternativa para o uso de EDTA devido a suas propriedades quelantes e de interferir com a adesão inicial das bactérias sobre dentina.

The aim of this study was to evaluate if the variation of the sodium hypochlorite (NaOCl) temperature and pH increase its antibacterial and dissolution abilities. It was also evaluated if the chitosan nanoparticles (CNPs) inhibit the bacterial growth and remove smear layer. Two hundred-sixty bovine dentin blocks were infected intraorally. The experimental solutions were 1% and 2.5% NaOCl at room temperature and 37oC. the solution was acidified at pH 5 and 7. The exposure times were 5 and 20 min. The specimens were analyzed pre- (control) and postirrigation. After that, the samples were incubated in BHI and analyzed again to evaluate the bacterial recolonization. These procedures were performed in duplicate to access the percentage of dentinal cleaning. The samples were rinsed with a final irrigation of CNPs and analyzed immediately to determine the chelating effect, or infected intraorally to evaluate its antibacterial ability. NaOCl showed antibacterial power and was able to significantly dissolve the biofilm regardless its temperature. NaOCl at acid pHs showed great antibacterial properties, however its dissolution ability decreased. The CNPs were able to remove significantly the smear layer and interfere with the bacterial growth on dentin. Therefore, the NaOCl temperature is not relevant when the solution was tested on multi-specie biofilms. The antibacterial power of NaOCl was inversely proportional to its pH, while its dissolution capacity was directly proportional. CNPs could be an alternative instead of EDTA due to its chelating properties and ability to interfere with the earlier bacterial adhesion on dentin.