Click chemistryan efficient toolbox for the design of chitosand-based hydrogels for biomedicine

Abstract

The present thesis was focused on the development of new gel-type biomaterials form chitosan withexcellent stimuli-responsive properties using different click reactions. To this end, in the first place,chitosan was endowed with specific functionalities, after the controlled insertion of furan, maleimide,thiol or tetrazole groups in the main chain of the biopolymer, maintaining its original biocompatiblecharacter. Hereafter, hydrogels with different size and chemical structure were synthesized by means ofclick type cross-linking reactions (Diels-Alder, thiol-Michael addition or nitrile imine-mediated tetrazoleenecycloaddition). The final physico-chemical, swelling, viscoelastic and morphological properties ofthe different hydrogel systems were studied. So that the new developed biomaterials would be competentin the biomedical field, biodegradability studies under specific enzymes, controlled drug release assays,mucoadhesion experiments with mucin, antibacterial studies against Escherichia coli and Staphylococcusaureus and short-term cytotoxicity assays were conducted, depending on the intended final application.