Effect of chromium(III) gallate complex on stabilization of collagen.

To improve the stability of the collagen, here we studied the interaction of chromium(III) polyphenolic complex, [Cr(GA)2] (GA: Gallic acid) with collagen using various spectroscopic techniques. Circular dichroism studies show that the [Cr(GA)2] and gallic acid did not induce any structural perturbations on the triple helix of the collagen. Both differential scanning calorimetric(DSC) data and micro-shrinkage temperature studies showed that [Cr(GA)2] stabilized the collagen by 6±1°C compared to gallic acid. Hydrodynamic studies revealed that the viscosity of collagen drastically reduced in the presence of [Cr(GA)2] while gallic acid did not. Fibrillation assay displayed a significant delay in fibril formation with Cr(III) complex compared to gallic acid treated collagen. The inhibition of fibril formation was further confirmed by microscopic data in which collagen fibres are seen with GA while [Cr(GA)2] treated collagen exhibit a thin microfibrils. From AFM studies, the d-periodicity of collagen was found to be decreased with [Cr(GA)2] while increased with gallic acid. The present study deliberate the advantage of metal complex containing polyphenolic ligand as crosslinking agent due to its synergistic effect of both metal center as well as polyphenolic groups in the stabilization of collagen structure.

Injectable alginate-O-carboxymethyl chitosan/nano fibrin composite hydrogels for adipose tissue engineering.

Injectable, biodegradable scaffolds are required for soft tissue reconstruction owing to its minimally invasive approach. Such a scaffold can mimic the native extracellular matrix (ECM), provide uniform distribution of cells and overcome limitations like donor site morbidity, volume loss, etc. So, here we report two classes of biocompatible and biodegradable hydrogel blend systems namely, Alginate/O-carboxymethyl chitosan (O-CMC) and Alginate/poly (vinyl alcohol) (PVA) with the inclusion of fibrin nanoparticles in each. The hydrogels were prepared by ionic cross-linking method. The developed hydrogels were compared in terms of its swelling ratio, degradation profile, compressive strength and elastic moduli. From these preliminary findings, it was concluded that Alginate/O-CMC formed a better blend for tissue engineering applications. The potential of the formed hydrogel as an injectable scaffold was revealed by the survival of adipose derived stem cells (ADSCs) on the scaffold by its adhesion, proliferation and differentiation into adipocytes. Cell differentiation studies of fibrin incorporated hydrogel scaffolds showed better differentiation was confirmed by Oil Red O staining technique. These injectable gels have potential in soft tissue regeneration.