High Substitution Synthesis of Carboxymethyl Chitosan for Properties Improvement of Carboxymethyl Chitosan Films Depending on Particle Sizes

This study investigated the effect of chitosan particle sizes on the properties of carboxymethyl chitosan (CMCh) powders and films. Chitosan powders with different particle sizes (75, 125, 250, 450 and 850 µm) were used to synthesize the CMCh powders. The yield, degree of substitution (DS), and water solubility of the CMCh powders were then determined. The CMCh films prepared with CMCh based on chitosan with different particle sizes were fabricated by a solution casting technique. The water solubility, mechanical properties, and water vapor transmission rate (WVTR) of the CMCh films were measured. As the chitosan particle size decreased, the yield, DS, and water solubility of the synthesized CMCh powders increased. The increase in water solubility was due to an increase in the polarity of the CMCh powder, from a higher conversion of chitosan into CMCh. In addition, the higher conversion of chitosan was also related to a higher surface area in the substitution reaction provided by chitosan powder with a smaller particle size. As the particle size of chitosan decreased, the tensile strength, elongation at break, and WVTR of the CMCh films increased. This study demonstrated that a greater improvement in water solubility of the CMCh powders and films can be achieved by using chitosan powder with a smaller size.

Protective Efficacy of Novel Oral Biofilm Vaccines against Lactococcus garvieae Infection in Mullet, Mugil cephalus

Lactococcus garvieae (L. garvieae) is an important pathogen that causes enormous economic losses in both marine and freshwater aquaculture. At present, antibiotics are the only option for farmers to reduce the losses caused by L. garvieae. However, the usage of antibiotics leads to environmental pollution and the production of drug-resistant strains of bacteria. Therefore, vaccination is preferred as an alternative method to prevent infectious diseases. In this study, we describe an effective approach to the production of an oral biofilm vaccine, using bacteria grown on chitosan particles to form biofilms, and thus providing an inactive pathogen that enhances the immune response in fish. We observed the formation of a biofilm on chitosan particles and administered the novel oral biofilm vaccine to fish. We analyzed the immune responses, including antibody production, phagocytic ability, albumin/globulin ratio and immune-related genes, of vaccinated and control groups of black mullet. Our results show that the phagocytic ability of the biofilm vaccine group was 84%, which is significantly higher than that of the control group, and the antibody production in this group was significantly higher compared with the other group. The mRNA expression levels of immune-related genes (TLR2, IL-1β, TNF-α) were significantly upregulated in the spleen after vaccination. In challenge experiments, the relative percent survival (RPS) was 77% in the biofilm vaccine group, 18% in the whole-cell vaccine group, and 0% in the chitosan particle group at 32 days post-vaccination. In addition, we also found that the relative percent survival (RPS) at 1 day post-vaccination was 74% in the biofilm vaccine group, 42% in the whole-cell vaccine group, and 26% in the chitosan particle group. In both long-term and short-term challenge experiments, the viability of the biofilm vaccine group was significantly higher than that of the whole-cell, chitosan particle and PBS groups. We conclude that based on its protective effect, the L. garvieae biofilm vaccine is better than the whole-cell vaccine when challenged several weeks after vaccination. In addition, the biofilm vaccine also has a greater protective effect than the whole-cell vaccine when challenged immediately after vaccination. Therefore, the biofilm vaccine might represent a novel method for the prevention and treatment of L. garvieae infection.

Kitosan Teradiasi Gamma 5 kGy Mempengaruhi Muatan Permukaan Nanopartikel MikroRNA

Nanoparticles are non-viral vectors with biodegradability and controlled release abilities that are widely used in gene transfer. Nanoparticles are said to be able to effectively combine and concentrate DNA and RNA in products to be delivered to various cells. Based on changes in microRNA expression in cancer, delivery using microRNA nanoparticles from outside the body is expected to be one of the therapeutic solutions. Irradiated chitosan is assumed to undergo cutting off the main polysaccharide group to produce a smaller molecular weight compared to nonirradiated chitosan. The desired irradiation process to reduce chitosan particle size so that it has better absorption efficiency into the cell needs to be further evaluated including looking at its effect on the final potential zeta. Zeta potential is important to ensure that the nanoparticles are positive enough to be able to enter the negatively charged cell membrane. Chitosan used was irradiated at a dose of 5kGy mixed with 1: 1 nucleic acid ratio. The results of zeta potential measurements showed the highest zeta potential values ​​of 15.27 mV and 13.63 mV obtained in the formula with chitosan-microRNA composition only. The measurement result of zeta potential of irradiated chitosan nanoparticles decreases the surface charge of the particles, this can reduce the potential of nanoparticles for the process of delivery into the cell. Keyword : Irradiated chitosan; nanoparticle; zeta potential

Alginate/Chitosan Particle-Based Drug Delivery Systems for Pulmonary Applications

Cystic fibrosis (CF) is a complex, potentially life-threatening disease that is most effectively treated through the administration of antibiotics (e.g., colistimethate sodium). Chronic infection with Pseudomonas aeruginosa is one of the most significant events in the pathogenesis of cystic fibrosis, and tobramycin is the treatment of choice for those patients with chronic P. aeruginosa infection who are deteriorating despite regular administration of colistimethate sodium. Effective treatment can be challenging due to the accumulation of thickened mucus in the pulmonary environment, and here we describe the results of our investigation into the development of alginate/chitosan particles prepared via precipitation for such environments. Tobramycin loading and release from the alginate/chitosan particles was investigated, with evidence of both uptake and release of sufficient tobramycin to inhibit P. aeruginosa in vitro. Functionalisation of the alginate/chitosan particles with secretory leukocyte protease inhibitor (SLPI) was shown to help inhibit the inflammatory response associated with lung infections (via inhibition of neutrophil elastase activity) and enhance their interaction with cystic fibrosis mucus (assayed via reduction of the depth of particle penetration into the mucus) in vitro, which have prospects to enhance their efficacy in vivo.

A nano-sized chitosan particle based electrochemical aptasensor for sensitive detection of P. aeruginosa

In this research, a glassy carbon electrode (GCE) was modified with nano-sized chitosan particles (NCs) by the drop-casting method for ultrasensitive detection of Pseudomonas aeruginosa (P. aeruginosa).

Utilization and Characterization of Oyster Shell as Chitosan and Nanochitosan

Oyster is one of bivalve groups widely consumed by human, thus, it results in producing huge waste shells affecting the environment. One way to increase the value of oyster shells is to process them into chitosan. This study aims to isolate chitin then synthesize it into chitosan and convert chitosan into nano-sized chitosan and analyze the characteristics. The steps to produce chitosan from waste shells included demineralization using HCl 1 N and deproteinization using NaOH 3%. The next step was to convert chitin into chitosan through a deacetylation process using NaOH 50%. After chitosan was formed, it was continued to convert chitosan into nano chitosan particles using ion gelation method with the addition of surfactant (tween 80) and crosslinker (TPP 0.1% and 0.5%). The results showed that yield of transformation chitin into chitosan was 61.1%. Meanwhile, the yield calculated from initial weight of raw material was 18.33% with deacetylation degree value equal to 89.14%. Based on morphological analysis using SEM, the size of chitosan particles was not distributed homogeneously that was in the range of 892 nm-1.54 μm, while the nano chitosan particle size obtained was uniformly formed in the range of 679 nm-910 nm.