Stimuli-responsive electrospun nanofibers with core-shell design for bioactive wound healing

Electrospun nanofibrous mats are widely investigated for wound-care applications due to their extracellular-matrix-like architecture, high surface area, and interconnected porosity, which support exudate management and gas exchange. Beyond passive coverage, advanced wound dressings increasingly aim to incorporate bioactive functions and stimuli-responsive behavior to better match the dynamic wound microenvironment. Here, we present a hybrid core–shell nanofibrous platform combining a thermo-responsive poly(N-isopropylacrylamide) (PNIPAM) core with a poly(ε-caprolactone) (PCL) shell. PNIPAM was synthesized in-house and formulated with glycine as a model amino-acid potentially relevant to wound-healing pathways. Coaxial electrospinning was employed to fabricate core–shell fibers in which the PNIPAM/glycine phase acts as an internal reservoir, while the external PCL layer provides mechanical integrity and a biodegradable protective interface. This architecture is designed to integrate responsiveness with structural stability in moist environments, enabling the development of biofunctional nanofibrous systems for localized drug delivery. The fabrication route avoids toxic solvents, supporting safer translation toward biomedical applications. Morphological uniformity and fiber distribution were evaluated by SEM, confirming continuous nanofibrous networks and homogeneous mat formation. FTIR spectroscopy was used to verify the characteristic chemical signatures of PNIPAM and PCL and to investigate glycine incorporation within the electrospun structure. Differential scanning calorimetry (DSC) was used to investigate the thermo-responsive behavior of the system in the physiological range, with particular focus on the volume phase transition temperature (VPTT) of PNIPAM and the influence of the core–shell architecture on the transition. Finally, in vitro degradation tests were performed under simulated physiological conditions to assess mass loss and structural integrity over time. Overall, this work highlights electrospun stimuli-responsive core–shell nanofibers as an innovative and green approach for wound management, integrating a biodegradable protective shell with a thermo-responsive core designed for the incorporation of bioactive components while avoiding toxic solvents during fabrication.