Chitosan

Crustacean and seaweed materials combined in a unique way could provide a sustainable alternative to plastic films. Materials with enhanced structure derived from crustaceans and seaweed could be part of a next-generation answer to the challenge of replacing petroleum-based plastic films, according to new research from North Carolina State University. Combining chitosan, a biopolymer that makes crab shells hard, with agarose, a biopolymer extracted from seaweed that is used to make gels, creates unique biopolymer composite films with enhanced strength. The films are also biodegradable, have antibacterial properties, repel water and are transparent. The findings could eventually lead to sustainable packaging films for food and consumer goods. "How do we find sustainable replacements for synthetic polymers?" asked Orlin Velev, S. Frank and Doris Culberson Distinguished Professor of Chemical and Biomolecular Engineering at NC State and corresponding author of a paper describing the research. "Synthetic polymers make very good films, but we want to replace them with natural biopolymers. The question becomes how do we adjust the joint structure of these natural polymers -- in our case, agarose and chitosan -- so we can have all the desirable properties of synthetic polymers inside a sustainable, biodegradable film?" It may not be enough to simply mix chitosan and agarose together. Velev says previous efforts to produce such mixtures reported improvements in properties, but when dried created gritty films that may lack the right strength. Instead, Velev and his collaborators took a different approach, reinforcing the agarose films with fibrillated colloidal scale material -- called soft dendritic colloids -- made from chitosan. The strong chitosan micro- and nanoscale fibrils are hierarchically branched to provide strength and stability to the agarose film where they are embedded. "It is challenging to modify natural polymers chemically, but we can alter their morphology and use them as composites," said Yosra Kotb, an NC State Ph.D. graduate and first author of the paper. "We use chitosan dendritic particles to reinforce the agarose matrix because of the compatibility of both materials leading to good mechanical properties; chitosan particles also have an opposite charge to agarose. When mixed, these charges are neutralized so the resulting materials also become more resistant to water." The biopolymer composites are about four times stronger than agarose films alone, the research shows, and also resist E.coli, a commonly studied bacterium. The paper also showed that a sheet made from biopolymer composite films greatly degraded after a month underground, while, for comparison, a common plastic sandwich baggie remained completely intact after the same period underground. "Interestingly, our composite is initially strongly antibacterial," Velev said, "but because it is made from natural materials, after some time bacteria will still colonize it -- so after a month underground it will biodegrade readily." Velev added that his lab will continue working to make improvements in the structure of the biopolymer composite films with the goal of eventually matching the properties of synthetic polymer ones. "If you package food, you want the package to be impermeable to oxygen and water," he said. "But natural materials are permeable, so we will continue to work to make our films more impermeable to water and oxygen." Increasing the scalability of the material production process is also one of the future goals. "How do you make the polymer substitute film in a continuous process that is rapid enough to make it in large enough amounts -- like papermaking?" Velev said. The findings appear in Cell Reports Physical Science. NC State has filed a patent application on the new biopolymer composite films and the process for creating them. The research has been supported by the National Science Foundation under grant CMMI-2233399, and partially by EFMA-2029327, CMMI-1825476 and CMMI-2134664.

Vancouver, British Columbia--(News - October 17, 2023) - Defence Therapeutics Inc. (CSE: DTC) ("Defence" or the "Company"), a Canadian biopharmaceutical company specialized in the development of immune-oncology vaccines and drug delivery technologies, is pleased to announce that systemic administration of novel AccuTOXTM-chitosan encapsulated formulation inhibits the growth of pre-established solid lymphoma resulting in their progressive shrinking over time. The conducted study had two main objectives: i) to test whether AccuTOXTM can be delivered systemically if encapsulated in chitosan-based nanoparticles, and ii) to assess whether this modality can synergize with immune-checkpoint blockers commonly used in the oncology clinic. The formulation was delivered twice with a 2 weeks interval and treated animals were followed for up to 40 days. The tumors in animals treated with AccuTOXTM-Chitosan injections along with anti-PD-1 co-administration regressed and exhibited a prolonged survival rate. "The AccuTOXTM molecule can be toxic if delivered unconjugated and/or systemically. The Defence team was able to bypass this limitation by encapsulating it into chitosan-based nanoparticles. This is a simpler and cheaper method compared to the use of antibodies, and may represent a key component of Defence's future encapsulation strategies," says Mr. Plouffe, CEO of Defence Therapeutics. Chitosan is a linear polysaccharide composed of randomly distributed β-(1→4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit), and has a number of commercial and biomedical uses. In addition to its agricultural and industrial applications, chitosan is often useful in bandages to reduce bleeding and as an antibacterial agent. It can also be used to help deliver drugs through the skin. Therefore, exploiting it as a delivery vehicle for unconjugated Accum® or its variants could revolutionize the future of molecular medicine by increasing the compounds specificity to tumor site while minimizing the needed dosage and thus, associated side effects. About Defence: Defence Therapeutics is a publicly-traded biotechnology company working on engineering the next generation vaccines and ADC products using its proprietary platform. The core of Defence Therapeutics platform is the ACCUM® technology, which enables precision delivery of vaccine antigens or ADCs in their intact form to target cells. As a result, increased efficacy and potency can be reached against catastrophic illness such as cancer and infectious diseases. For further information: Sebastien Plouffe, President, CEO and Director P: (514) 947-2272 Splouffe@defencetherapeutics.com Cautionary Statement Regarding "Forward-Looking" Information This release includes certain statements that may be deemed "forward-looking statements". All statements in this release, other than statements of historical facts, that address events or developments that the Company expects to occur, are forward-looking statements. Forward-looking statements are statements that are not historical facts and are generally, but not always, identified by the words "expects", "plans", "anticipates", "believes", "intends", "estimates", "projects", "potential" and similar expressions, or that events or conditions "will", "would", "may", "could" or "should" occur. Although the Company believes the expectations expressed in such forward-looking statements are based on reasonable assumptions, such statements are not guarantees of future performance and actual results may differ materially from those in the forward-looking statements. Factors that could cause the actual results to differ materially from those in forward-looking statements include regulatory actions, market prices, and continued availability of capital and financing, and general economic, market or business conditions. Investors are cautioned that any such statements are not guarantees of future performance and actual results or developments may differ materially from those projected in the forward-looking statements. Forward-looking statements are based on the beliefs, estimates and opinions of the Company's management on the date the statements are made. Except as required by applicable securities laws, the Company undertakes no obligation to update these forward-looking statements in the event that management's beliefs, estimates or opinions, or other factors, should change. Neither the CSE nor its market regulator, as that term is defined in the policies of the CSE, accepts responsibility for the adequacy or accuracy of this release. To view the source version of this press release, please visit