Chitosan-sodium percarbonate-based hydrogels with sustained oxygen release potential stimulated angiogenesis and accelerated wound healing.

The prolonged hypoxic conditions hinder chronic wounds from healing and lead to severe conditions such as delayed re-epithelialization and enhanced risk of infection. Multifunctional wound dressings are highly required to address the challenges of chronic wounds. Herein, we report polyurethane-coated sodium per carbonate-loaded chitosan hydrogel (CSPUO2 ) as a multifunctional dressing. The hydrogels (Control, CSPU, and CSPUO2 ) were prepared by freeze gelation method and the developed hydrogels showed high porosity, good absorption capacity, and adequate biodegradability. The release of oxygen from the CSPUO2 hydrogel was confirmed by the increase in pH and a sustained oxygen release was observed over the period of 21 days, due to polyurethane (CSPU) coating. The CSPUO2 hydrogel exhibited around 2-fold increased angiogenic potential in CAM assay when compared with Control and CSPU dressing. CSPUO2 also showed good level of antibacterial efficacy against E. coli and S. aureus. In a full-thickness rat wound model, CSPUO2 hydrogel considerably accelerated wound healing with exceptional re-epithelialization granulation tissue formation less inflammatory cells and improved skin architecture highlighting the tremendous therapeutic potential of this hydrogel when compared with control and CSPU to treat chronic diabetic and burn wounds.

A study of the comparative effect of cerium oxide and cerium peroxide on stimulation of angiogenesis: Design and synthesis of pro-angiogenic chitosan/collagen hydrogels.

Poor angiogenesis at injury site is a major problem in chronic wounds, which could lead to limbs amputation in adverse cases. To overcome this issue, several efforts have made in literature and by our group as well to develop pro-angiogenic agents. For this purpose, metal oxides due to their oxidative potential have been studied and found very attractive agents. Cerium oxides are proven to be non-toxic and their biological studies have already proved their importance in preventing chronic inflammation, and neurological diseases among several others by modulating the intracellular reactive oxygen species. In current study, we report the synthesis and neovascularization activity of cerium oxide and cerium peroxide nanoparticles when loaded into chitosan and collagen hydrogel. The hydrogels were characterized by FTIR, SEM and XRD. The pro-angiogenic behavior of these hydrogels was studied by in-vivo CAM assay. It was found that cerium peroxide loaded material showed significantly increase in angiogenesis as compared to cerium oxide loaded materials. It was demonstrated that cerium peroxide hydrogels enhanced the angiogenic capability in CAM assay as compared to cerium oxide and hence holds good potential for chronic ulcer and burn wounds healing.

Biomimetic nitrogen doped titania nanoparticles as a colorimetric platform for hydrogen peroxide detection.

Nanoparticles proved a viable alternative to the already used sensing and diagnostics methods due to their low cost, good stability, easy availability and easy synthesis. In the present approach, nitrogen doped titania nanoparticles are prepared through freeze drying method, and subsequently stabilized through ionic liquid. These nanoparticles were characterized through various techniques such as X-ray diffraction (XRD), Fourier transformation infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), BET pore size and surface area analyzer, X-ray photoelectron spectroscopy (XPS) and UV-Visible diffuse reflectance spectroscopy (UV-Vis. DRS). The synthesized nitrogen doped titania nanoparticles were proved to be a novel peroxidase mimetic with great potential to catalyze oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H2O2) to form a blue color product. As a proof of concept, this new enzyme mimic was used as a robust nanoprobe for the detection of hydrogen peroxide with improved analytical characteristics. A linear response for hydrogen peroxide detection was obtained in the range of 10-300µmol/L, with a detection limit of 2.5µmol/L. Taking into account the valuable intrinsic peroxidase activity, the present work may find widespread applications in the field of sensors and biosensors for diverse applications.