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.

Fungal infection with Candida of dentures is a common complication. The adhesion of microorganisms such as Candida is influenced by material properties such as surface charge, hydrophobicity and roughness. The formation of oral biofilms is associated with caries, periodontitis or denture stomatitis. It is therefore important to prevent the formation of biofilms, also because antifungal agents are of little help.
The polymer polymethyl methacrylate (PMMA) is widely used for denture fabrication due to its biocompatibility, but it is susceptible to biofilm formation. Therefore, research into strategies to endow dentures with antifungal properties is important.

Listeriosis is a foodborne infectious disease caused by the pathogen Listeria monocytogenes and is particularly serious for pregnant women and immunocompromised persons. The pathogen is spread mainly through spoiled and contaminated food or animal feed. Methods for the detection of Listeria monocytogenes (LM) on surfaces in the food industry have been developed to control the spread of the pathogen, but these are time-consuming and require special equipment. In the presented study, a fluorescence sandwich immunoassay was developed using a chitosan cellulose nanocrystal (CNC) membrane to detect Listeria monocytogenes on surfaces.

Dental erosion is the demineralization of the hard tooth substance caused by acids. Particularly in industrialized countries this is an increasing problem due to changes in drinking and eating habits in recent decades. Additionally, the teeth surface is eroded by mechanical interaction like brushing. To substantially reharden demineralized enamel, the development of appropriate prophylaxis and therapy is important. HMC presents two studies that tested toothpaste and mouth rinses containing chitosan.

In recent decades, there have been major advances in regenerative medicine, such as the treatment of severe nerve injuries. Implants used as scaffolds for nerve cell regeneration are often made of biodegradable polymers, such as chitosan. Below, we present a study that investigated the degradation and stability of tubular chitosan-based implants.