Novo sistema de entrega a base de um hidrogel injetável fotopolimerizável (GelMA) como estratégia de desinfeção endodôntica inteligente (on-demand)e regeneração de tecidos orais

Abstract

This study aimed to synthesize, characterize and evaluate a new on-demand drug delivery system for endodontic disinfection in regenerative endodontics. The synthesis of the gelatin methacrylate hydrogel (GelMA) was carried out and subsequently different potentially antimicrobial particles were added. The analysis in Scanning Electron Microscopy / Dispersion Spectroscopy (SEM / EDS) characterized the morphology and functionalization of GelMA. The properties of the GelMA evaluated were: sorption, degradation, drug release, compression module, and cytotoxicity. The antimicrobial properties were evaluated through the inhibition halo, direct contact test, and inhibition of the formation of bacterial biofilm on the surface of the materials, through the counting of colony-forming units (CFU) and visualization of images in confocal microscopy. The biocompatibility and biodegradation in vivo were analyzed using an optical microscope, for the presence of luminous structures containing red blood and inflammatory cells, at the same time that the biodegradation of the hydrogel was evaluated, after filling small subcutaneous pockets. Statistical analyzes were performed according to each analysis, considering p <0.05 as statistically significant. Results: GelMA modified with chlorhexidine-loaded halloysite nanotubes (CHX) showed adequate mechanical properties, degradation rate sustained release of CHX for ablation of infection, and good biocompatibility. The modified GelMA showed minimal localized inflammatory responses, supporting its ability for drug delivery applications. Besides, the incorporation of nanotubes loaded with CHX reduced the mechanical properties, increased the sorption ratio, and decreased the degradation rate of the hydrogels. It is important to note that the presence of CHX-loaded nanotubes inhibits bacterial growth with minimal cellular toxicity. Aliquots containing antibiotics led to a reduction in the viability of SHEDs but were not considered toxic. Considering the initial characterization provided in this study, it is possible to affirm that we have developed a new strategy for delivering on-demand drugs for regenerative endodontic therapy through the modification of a GelMA hydrogel loaded with antimicrobial agents.