The corona virus disease COVID-19 has changed the world. To combat the pandemic, researchers and companies around the world are working to develop vaccines and medicines. Chitosan also has potential in the area of vaccine development and functionalization of protective equipment such as respirators. We have prepared summaries of recent publications on chitosan as an aid in the fight against corona.

Hepatocellular carcinoma is a solid tumor that exhibits severe angiogenesis, cell cycle dysregulation, and evasion of apoptosis. Late diagnosis in a large proportion of patients is making the carcinomas inoperable, and various chemotherapeutic agents are used. Due to the numerous side effects of known chemotherapeutic agents, intensive research is performed on the use of natural products and their synthetic analogues. The authors of the presented study investigated the effect of carboxymethyl chitosan oligosaccharides on the growth of hepatocellular tumors in mice.

The global spread of SARS-CoV-2 can only be contained through vaccine development. Vector vaccines (DNA and viral) can be produced rapidly and inexpensively with current synthesis technologies. Challenges with DNA vaccines include degradation by DNases, inefficient uptake by antigen-presenting cells, and low immunogenicity. The Quil-A-loaded chitosan particulate adjuvant system (QAC) enables transport of plasmid DNA directly to target cells and delayed release over time. Here, we present two recent studies about chitosan-based delivery systems for vaccines.

Chitosan and chitosan derivatives are promising biopolymers for nasal or vaginal drug delivery using micro- or nanoparticles. However, the pH-dependent solubility of chitosan and excessive water uptake in the presence of ions is suboptimal. Water uptake can result in rapid initial release of the drug due to collapse of the chitosan-based transport vehicle. To stabilize the drug release, research is being conducted to modify the polymer structure by physical crosslinking. Aim of the presented study was to investigate the influence of microparticle composition, in particular the amount of ion crosslinker (CF) introduced, on the release profile of water-soluble drugs from the chitosan matrix.