Optimization of nanocomposite hydrogels for the treatment of diabetic foot ulcers

Abstract

In the present, diabetic foot ulcers are a very common pathology all around the world, and most products in the market offer to solve a specific need for the patient such as battling infection or allowing wound debridement. In such regard biomaterial-based nano cues with multi-functional characteristics have been engineered with high interests around the globe. The ease in fine tunability with maintained compliance makes an array of nanocomposite biomaterials outstanding candidates for the biomedical sector of the modern world. In this context, the present work intends to tackle the necessity of alternatives for the treatment of diabetic foot ulcers through the formulation of nanoclay/polymer-based nanocomposite hydrogels. Laponite RD, a synthetic 2-Dimensional nanoclay that becomes inert when in physiological environment, while mixed with water, becomes a clear gel with interesting shear-thinning properties. Optimization of the hydrogel formulation is approached by preparing the samples at several concentration ratios (Nanoclay-Chitosan and Nanoclay-Gelatin; 35-95% of nanoclay in steps of 15%), where the mechanical properties such as viscosity, shear-thinning and injectability are observed to change. Zero shear viscosity of the samples was calculated by the Cross Model Equation, and was observed to increase for the chitosan samples as the nanoclay ratio increased (3.41x103 - 6.44x104 Pa⋅s at 35-65% of nanoclay, respectively) and then decreasing after that concentration of nanoclay. Gelatin had the opposite behavior, while both formulations having a zero shear viscosity of ~3.5x104 Pa⋅s at 95% of nanoclay. Injection force values of the samples in 3 mL plastic syringes with 20G needles, ranged between 1 and 4 N in average, approximately. Adding Laponite RD to chitosan or gelatin, allows for the modification of mechanical properties of such materials. The setup explored in this research allows for a promising polymeric matrix that can potentially be loaded with active compounds for antibacterial support in foot ulcers, as well as enzymes for wound debridement.