Antibacterial Coatings Based on Chitosan for Pharmaceutical and Biomedical Applications.

The risk of bacterial colonization of abiotic surfaces of biomedical devices poses important challenges for the pharmaceutical and biomaterials science fields. In this scenario, antibacterial coatings have been developed, using a number of different molecules and materials. Among them, chitosan is a non-cytotoxic, biocompatible biopolymer with an inherent antimicrobial activity that has been already used in a wide variety of healthcare and industrial applications. Herein, chitosan-based antibacterial coatings are critically surveyed, with a special emphasis on their production methods, pharmaceutical and biomedical applications, along with their pros and cons, and finally highlighting the key challenges to be faced and future perspectives in this field.

In vitro evaluation of anti-calcification and anti-coagulation on sulfonated chitosan and carrageenan surfaces.

In recent years, great effort has been devoted to the development of biomaterials that come into contact with blood. The surfaces of these materials need to be of suitable mechanical strength, and present anti-thrombogenic and anti-calcification properties. Chitosan is a natural polymer that has attracted attention due to its potential to act as a biomaterial. However, chitosan contains amino groups in its structure that may promote thrombogenesis and calcification. A strategy to reduce these properties constitutes the introduction of sulfonate groups (R-SO3-) in the chitosan chain. Another interesting biopolymer with similar characteristics to those of heparin is carrageenan, which has sulfate groups in its structure. As such, we evaluated "in vitro" calcification and thrombogenic processes on surfaces of pristine and sulfonated chitosan and on polyelectrolyte complexes (PEC) of chitosan and carrageenan. Results indicate that PEC demonstrate significant reductions in calcification and thrombogenic potential, probably due to the presence of sulfonate groups in both the carrageenan and treated chitosan.