Preparação e caracterização de matrizes nanoparticuladas na base de óxido de zinco e polímeros biodegradáveis para a liberação controlada de antimicrobianos

Abstract

In the present work three systems of controlled release of doxycycline and curcumin for agricultural use were developed as nanoparticles of zinc oxide (ZnO) carrying doxycycline, alginate-chitosan nanoparticles carrying curcuma and polymeric nanofibers of polycaprolactone-alginate and gelatin carrying curcuma. The antimicrobial activity and release kinetics were evaluated in each system under study. Nanoparticles of zinc oxide (ZnO) were prepared and characterized by microwave-assisted sol-gel, hydrothermal methods. The compounds were tested against the bacteria E. carotovora, Pantoea sp, E. coli and S. aureus that exhibited antimicrobial action. The antimicrobial effect was also evaluated by photocatalytic effect, where the efficiency of the treatment was evidenced by the formation of surface defects such as oxygen and interstitial zinc vacancies. EPR "Spin Trap" studies have demonstrated the relationship between surface defect density and free radical production as the hydroxyl radical. Studies of doxycycline desorption uptake in zinc oxide (ZnO) nanoparticles have shown matrix efficiency as a platform for the controlled release of cationic drugs such as doxycycline. The alginate-chitosan polymer nanoparticles carrying curcuma had particle sizes between 125 and 500 nm. They were assessed against the E. coli and S. aureus bacteria that exhibited no antimicrobial activity. The release studies showed pH dependence. The obtained polymer nano-fibers had diameters between 215-1000 nm. Coating of polycaprolactone-alginate concentric fiber extended the in vitro release time of curcuma. The polymer fibers exhibited no antimicrobial action on the tested bacteria.