Hybrid functional biopolymers as advanced nanocomposite for catalytic drug delivery and sensing applications

Abstract

Nanocomposites offer unique combinations of property and design, a major limitation newlinein the conventional microcomposites. In this class, hybrid functional bionanocomposites newlinehave been introduced as an advanced and versatile generation providing miniaturisation newlineas well as hybridisation between organic and inorganic functions. Be it applications like newlinedrug delivery, sensing or catalysis, these hybrid bionanocomposites on par have proved newlinetheir excellence. newlineIn the thesis, these studies laid the grounds framing the main objective to investigate newlinethe feasibility of three different polysaccharides, viz., chitosan, alginate and agarose to newlineform hybrid bionanocomposites which are variedly functional. The initial work newlineintroduces chitosan gel and tea as two new precursors for the synthesis of carbon dots newline(CD) having particle size less than 10 nm. The CDs from both the sources showed newlinebright blue fluorescence under UV lamp with sharp peaks in their photoluminescence newline(PL) spectra. The unique property variance between these two carbon dots was observed newlinein their net surface charge with chitosan gel CDs showing positive value (and#950;= +27.8 mv), newlineand tea CDs showing negative value (and#950;= 39.2 mV). In addition, the photoluminescent newlineproperties of chitosan CDs at different pH conditions and on incorporation of silver and newlinegold nanoparticles were examined. Interestingly, when chitosan carbon dots combined newlinewith calcium alginate (CA) beads formed a protective coat on the beads. These carbon newlinedots coated alginate beads (CA-CD) showed exceptional stability at room temperature newline(even after 60 days) and also at higher temperature. The CA-CD beads showed their newlineproficiency as a pH dependent drug delivery vehicle taking tetracycline (TC) and newlinetetracycline:and#946;-cyclodextrin (ß-TC) as model drug systems. The TC loading was 35% for newlineCA and 77% for CA-CD, and ß-TC loading was 48% for CA and 90% for CA-CD. A newlinemaximum drug release at pH 1 was obtained with 70% for CA-CD and 37% CA at 96 h. newlineHowever, in case of ß-TC loading the delivery rates were slower showing 61% relea