One‑Step fabrication method of insulin‑loaded polycaprolactone nanofibres by blend electrospinning for diabetic wound care

Effective management of diabetic wounds is a significant clinical challenge. Topical insulin shows therapeutic promise, but its delivery and stability require the use of advanced systems. This study aimed to develop and comprehensively characterise insulin-loaded Poly(ε-caprolactone) (PCL) nanofibres fabricated via a one-step blend electrospinning technique, as a potential platform for sustained insulin delivery in diabetic wound care. PCL nanofibres containing varying insulin concentrations were prepared using hexafluoroisopropanol (HFIP). The nanofibres were extensively characterised for their morphology, physicochemical properties (including thermal and chemical integrity), mechanical strength, surface wettability, insulin encapsulation efficiency (EE), and in vitro release kinetics. The stability of free insulin in solution was also assessed for comparison. Insulin incorporation significantly reduced nanofibre diameter (to ∼ 250 nm) and markedly enhanced tensile strength and Young's modulus without compromising elasticity, yielding mechanical properties within reported physiological ranges. An EE of approximately 78 % was achieved. In vitro studies demonstrated sustained insulin release over 14 days. Crucially, comparative analyses of release samples, contextualised by free insulin degradation studies, revealed that PCL nanofibre encapsulation conferred significant protection against insulin degradation compared to insulin in solution. The developed insulin-loaded PCL nanofibres, combining favourable physicochemical and mechanical properties with sustained release and enhanced protein stability, represent a promising approach for advanced diabetic wound dressings, potentially reducing dressing change frequency and improving therapeutic outcomes.