Novas rotas químicas e físicas para o preparo de hidrogéis baseados em polissacarídeos para potencial uso como biomateriais

Abstract

Hydrogels are extensively used as biomaterials due to their versatile nature. The unique characteristics of hydrogels are closely tied to their crosslinking methods, and their properties can be fine-tuned by optimizing the preparation process. This thesis explores novel routes for creating hydrogels with specific properties. In the first Chapter, we introduce a fresh approach for preparing a chitosan (CHT) and methacrylated synthetic polymer (PVA-MA) hydrogel through aza-Michael crosslinking with boric acid as a catalyst. This method is not only straightforward but also results in a mechanically robust and stable hydrogel. The second Chapter details the creation of a pectin (Pct) hydrogel crosslinked by disulfide bonds, which can be broken and reformed in response to the redox conditions of the environment. This hydrogel exhibits redox responsiveness and self-healing properties, making it a potential candidate for drug release applications. Chapter three outlines the preparation of an imine-crosslinked hydrogel using carboxymethyl chitosan (CMCHT) and aldehyde-functionalized hydroxyethyl cellulose (HEC-Ald). This unique approach involves acetal grafting and subsequent acid hydrolysis to reveal the aldehydes, ensuring saccharide monomer preservation. The resulting hydrogel possesses in situ forming capabilities, self-healing properties, and pH-responsiveness. The final chapter presents a hydrogel formed through polyelectrolyte complexation between QT and Pct. This hydrogel is prepared using a novel semi-dissolution/acidification method, resulting in mechanically stable and uniform materials, highlighting the efficiency of this approach. In summary, this thesis investigates novel crosslinking methods and demonstrates their effectiveness in producing hydrogels with valuable properties for biomedical applications.