Hidrogelovi polivinil-alkohola i hitozana sa elektrohemijski sintetisanim nanočesticama srebra za medicinske primene

Abstract

Cilj ove doktorske disertacije bila je sinteza novih biomaterijala, hidrogelova polivinil-alkohola i hitozana, sa i bez grafena, sa elektrohemijski inkorporisanim nanočesticama srebra i njihova detaljna karakterizacija u cilju ispitivanja mogućnosti primene u obliku antibakterijskih obloga za rane. Hidrogelovi srebro/polivinil-alkohol/hitozan i srebro/polivinil-alkohol/hitozan/grafen su dobijeni metodom zamrzavanja i odmrzavanja, praćenom elektrohemijskom in situ sintezom nanočestica srebra unutar polimernih matrica hidrogelova, nakon bubrenja u rastvoru Ag+ jona. Detaljna karakterizacija dobijenih hidrogelova je izvršena u cilju ispitivanja njihove strukture, morfologije, hemijskog sastava, mehaničkih i termičkih svojstava, kao i oblika, dimenzija i strukture sintetisanih nanočestica srebra. Ispitan je uticaj sadržaja hitozana na efikasnost elektrohemijske sinteze nanočestica, kao i na strukturu i svojstva samih hidrogelova. Karakterizacija u in vitro uslovima je obuhvatala ispitivanje sposobnosti bubrenja svih dobijenih hidrogelova i kinetike otpuštanja srebra u fiziološki relevantnim uslovima (pH 7,4, 37 ºC), kao i određivanje antibakterijskih svojstava i biokompatibilnosti dobijenih materijala. Rezultati ove disertacije su pokazali da dobijeni nanokompozitni hidrogelovi imaju visok potencijal za primenu kao aktivne obloge za rane sa jakim antibakterijskim efektom, koji se postiže kontrolisanim otpuštanjem elektrohemijski sintetisanih nanočestica srebra. Dobijeni rezultati su takođe pokazali povoljan efekat hitozana, kako na samu elektrohemijsku sintezu nanočestica srebra, tako i na fizičko-hemijska i antibakterijska svojstva dobijenih hidrogelova, tako da se ovi materijali mogu smatrati pogodnim kandidatima za dalja ispitivanja u oblasti biomedicinskih materijala. Ključne

The aim of this doctoral dissertation was the synthesis of new biomaterials, poly(vinyl alcohol) and chitosan hydrogels, with and without graphene, with electrochemically incorporated silver nanoparticles, and their detailed characterization in terms of potential applications as antibacterial wound dressing materials. Silver/poly(vinyl alcohol)/chitosan and silver/poly(vinyl alcohol)/chitosan/graphene hydrogels were obtained via the freezing-thawing method, followed by in situ electrochemical synthesis of silver nanoparticles inside hydrogel matrices, previously swollen in Ag+ ion solutions. Extensive characterization of the obtained hydrogels was carried out in order to examine their structure, morphology, chemical composition, mechanical and thermal properties, as well as the shape, size and structure of the synthesized silver nanoparticles. The effect of chitosan content on the electrochemical synthesis yield and on the structure and properties of the synthesized hydrogels was also investigated. In vitro characterizations included the investigation of the hydrogels’ swelling properties and silver release kinetics in physiologically-relevant environment (pH 7.4, 37 ºC), as well as the determination of antibacterial properties and biocompatibility. The results of this dissertation demonstrated that the synthesized nanocomposite hydrogels exhibited compelling potential for applications as active wound dressings with potent antibacterial effect, achieved through controlled release of the electrochemically embedded silver nanoparticles. The significant beneficial chitosan influence on both the electrochemical synthesis of silver nanoparticles, and the physicochemical and antibacterial properties of the hydrogels was proven. Therefore, these materials could be considered as apt candidates for further research in biomedical materials field.