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The present work describes the development of a novel wound dressing material based on nano-biotechnological intervention by caging plumbagin on silver nanoparticle (PCSN) as a multi-site cross-linking agent of collagen scaffolds with potent anti-microbial and wound healing activity. Cross-linking of collagen with PCSN enhanced the physical, thermal, and mechanical properties along with the kinetics of micro structural fibril assembly of the collagen molecule. FTIR and CD analysis revealed that cross-linking of collagen using PCSN did not induce any structural changes in the collagen molecule. Further, cross-linking of collagen with PCSN resulted in uniform alignment of collagen fibrils to form orderly aligned porous structured scaffolds with potent anti-bacterial activity that in turn enhanced its ability to promote cell proliferation and wound healing. The cross-linking ability, and biochemical and therapeutic properties of plumbagin caged silver nanoparticles were attributed to the cumulative effect of plumbagin and silver nanoparticles because individual molecules had minimal effect on these parameters.

Stabilization of collagen for various applications employs chemicals such as aldehydes, metal ions, polyphenols, etc. Stability against enzymatic, thermal and mechanical degradation is required for a range of biomedical applications. The premise of this research is to explore the use of nanoparticles with suitable functionalization/encapsulation to crosslink with collagen, such that the three dimensional architecture had the desired stability. Collagen solution prepared as per standard protocols is treated with chromium(III) oxide nanoparticules encapsulated within a polymeric matrix (polystyrene-block-polyacrylic acid copolymer). Selectivity towards encapsulation was ensured by the reaction in dimethyl sulfoxide, where the PS groups popped out and encapsulated the Cr(2)O(3). Subsequently when immersed in aqueous solution, PAA units popped up to react with functional groups of collagen. The interaction with collagen was monitored through techniques such as CD, FTIR, viscosity measurements, stress analysis. CD studies and FTIR showed no degradation of collagen. Thermal stability was enhanced upon interaction of nanostructures with collagen. Self-assembly of collagen was delayed but not inhibited, indicating a compete binding of the metal oxide encapsulated polymer to collagen. Metal oxide nanoparticles encapsulated within a polymeric matrix could provide thermal and mechanical stability to collagen. The formed fibrils of collagen could serve as ideal material for various smart applications such as slow/sustained drug release. The study is also relevant to the leather industry in that the nanostructures can diffuse through the highly networked collagen fibre bundles in skin matrix easily, thus overcoming the rate limiting step of diffusion., (Copyright © 2012 Elsevier B.V. All rights reserved.)

The in vitro susceptibility pattern with respect to lomefloxacin was determined in case of 1009 bacterial isolates from clinical specimens with varying susceptibility to commonly used antimicrobial agents. The MIC50 and MIC90 values of lomefloxacin for the Gram negative bacilli showed susceptibility value ranging between 0.12 to 4.0 micrograms/ml, while 90 per cent of the streptococci tested were inhibited only at 16 micrograms/ml. Lomefloxacin was comparable in activity to enoxacin and ciprofloxacin but it was more active than norfloxacin and nalidixic acid.