Fabrication of Chitosan-Alginate /Carboxymethyl Cellulose Microcarriers for Delivery of Bioactive Agents

Abstract

Recent advancements in developing an efficient system for delivery of bioactive particles viz. enzymes, therapeutic peptides and even nanoparticles are gaining importance nowadays. Particularly, microcarriers developed using biopolymeric systems are currently under investigation so as to deliver the required material with high efficiency, facilitating their controlled degradation-driven release without posing toxicological implications. Studies have been done in the recent past to develop an efficient carrier system employing biopolymers. The conventional approaches followed for their fabrication are either expensive or may cause toxicity, which restricts their widespread application. The main objective of this research was to emerge with a cost effective yet efficient template system for proficient delivery of various active ingredients ranging from enzyme to bactericidal silver nanoparticles. Microcarriers with a unique combination of biopolymeric system employing chitosan, alginate and carboxymethyl cellulose was synthesized through layer by layer assembly onto which α-amylase was immobilized through in-situ and ex-situ immobilization and silver nanoparticles were synthesized separately and surface immobilized. Immobilization of 73% and 75% of the highest feed amount was achieved by microcarriers based on chitosan-alginate complex and CMC-alginate complex respectively through surface immobilization. Through in-situ immobilization 83% of the feed amount was immobilized into the core particles. Total amount of enzyme immobilized through in-situ immobilization was 9 times higher than that immobilized through surface immobilization. Efficient controlled release profile was at pH7 was observed. Cumulative release of 96 % till day 6 was achieved for microcarriers with surface immobilized enzyme, whereas cumulative release of 40% and 25% was obtained by microcarrier of biopolymeric combination chitosan-alginate and CMC-alginate respectively with in-situ immobilized enzyme. On the basis of final concentration of biopolymer utilized to form biopolymeric layering, immobilization and release efficiency; microcarriers with chitosan-alginate biopolymeric layering illustrates better immobilization efficiency and release profile. As 0.1mg/ml concentration of chitosan with high molecular weight and 85% DD has more functional groups and chain length when compared to 1mg/ml Carboxymethyl cellulose. Better release profile of chitosan-alginate complex is due to increased porosity of the complex at pH7. The resulting microcarriers with biopolymeric combination of chitosan-alginate were utilized as a carrier for biogenically synthesized silver nanoparticles Biopolymeric microcarriers coated with silver nanoparticles were combined with chitosan solution to form bionanocomposite (BNC) film. The silver nanoparticles coated microcarriers as well as bionanocomposite films illustrated good antibacterial activity against diverse bacterial strains, i.e. against E.coli(gram negative) and B.substilis(gram positive).BNC film was used for the preservation of grapes under double layer (grape wrapped in film and placed in sealing bag) and single layer (grape wrapped only in film) preservation conditions. Under both the preservation conditions; grapes wrapped BNC film had better physical appearance than then negative and positive controls till day 7 .Conclusively, these preliminary findings suggest this co-polymeric system to be a versatile carrier which has a dual role for the controlled release of bioactive molecules without affecting its efficacy.