Organic–Inorganic Hybrid Nanofiber Membranes by Electrospinning: Engineering Features and Cytocompatibility

Organic–inorganic (O/I) hybrid fibrous scaffolds represent a cutting-edge attempt for replicating the extracellular matrix (ECM) in tissue engineering. This study introduces an O/I hybrid composed of borosilicate-calcium elements incorporated with poly(ε-caprolactone) (PCL) using an eco-friendly, in situ sol–gel process. The purpose of this research was to electrospin this hybrid composition into nanofibrous mats and investigate the impact of the electrospinning parameters on membrane properties. Critical electrospinning parameters (distance, flow rate, and voltage) were optimized to refine spinning behavior and assess their influence on fiber’s morphology and diameter, being optimal conditions were achieved with a distance of 12 cm, a flow rate between 125 and 150 μL·h –1, and a voltage in the range of 14–17 kV. Based on these conditions, two scaffolds with different fiber diameters (∼65 and 116 nm) were fabricated and compared. A homogeneous distribution of the inorganic phase inside the PCL matrix was successfully achieved, and the presence of hydrogen-bonding interactions between the polymer and the silica network was confirmed. Mechanical properties were improved by the introduction of borosilicate compositions, while the scaffold with the thinnest fibers presented the higher Young’s modulus and tensile strength. Contrary to polymer membrane control, the fibrous O/I hybrid showed a hydrophilic character, with distinct wetting properties depending on fiber diameter. In vitro acellular studies proved superior degradability and bioactivity of the hybrids, confirmed by surface apatite formation, compared with the neat PCL membrane. Higher cell proliferation was exhibited by the hybrids and the best cytocompatibility was favored by the lower fiber diameter. This sustainable, interdisciplinary approach to material design strengthens the development of green, next-generation materials with potential for bionanohybrid applications, particularly for tissue engineering.