Formulation and Complex Morphological Characterization of Core-Shell Fibrous Mats for Chronic Wound Healing

In the recent past, one of the major challenges of the pharmaceutical industry was to overcome the poor aqueous solubility and permeability of new drug candidates, leading to their low bioavailability [1]. To solve these problems, novel structures were developed involving the polymer-based nanofibrous drug delivery systems [2,3]. The unique properties of the nanofibers as the high porosity with interconnected pore network and the increased surface area of the fibrous sheets, together with the active pharmaceutical ingredients can be embedded into the polymeric matrix carrier in an amorphous state, could lead to an increased dissolution and thus the bioavailability of drugs with a lower solubility [4,5]. Due to their structure, the formulation of nanofibrous materials loaded with different drugs have been widely used as drug delivery systems, scaffolds for tissue engineering and wound bandage. Electrospinning is a well controllable, simple and cost-effective technique for preparing matrices with nanometer-sized fibers with similar features and morphologies to the extracellular matrix (ECM) [6]. The ECM is the non-cellular component presents within all tissues and organs and plays a vital role in the wound healing process [7]. Therefore from those materials which can mimic their structure are believed to stimulate cell proliferation and could help the wound healing [6]. The diverse field of application of the nanofibrous materials required adequate functionalityrelated characteristics. One of the emerging improvements is the development of a bi-component core-shell fiber structure [8], which can offer several benefits for these samples: the core polymer/ composite can provide the required mechanical, physicochemical properties, and can control the release of the incorporated drug(s). The shell materials could preserve the unstable active pharmaceutical ingredients embedded into the core from the unfavorable environmental effect, which can increase the hydrophilicity and the biocompatibility of the fibrous samples. Besides that, one of the significant advantages of this core-shell nanostructures lies in the potential to tailor release properties of the incorporated drug and combine features of different polymers to achieve the required functionality-related characteristic and mechanical properties also [5].