Electrospun PCL/BG composite scaffolds: processing, optimization and surface modification to improve wettability and...

The design of biomedical devices for tissue engineering has attracted significant research interest since the late twentieth century. Among the available fabrication techniques, electrospinning has emerged as a versatile approach for producing fibrous scaffolds for various applications, such as wound dressing and healing, as well as bone tissue regeneration. In this context, the synergistic use of bioactive glass (BG) has gained significant attention due to its well-established properties including osteogenesis, osteoinduction, angiogenesis, wound healing, soft tissue repair and antibacterial effects. In this work, S53P4_MS, (composition in mol.%: SiO₂ 53.8, P₂O₅ 1.7, Na₂O 7.7, CaO 21.8, MgO 5, SrO 10), a novel melt-derived composition with remarkable thermal and biological properties, was employed as a powdered ceramic filler in electrospun poly(ε-caprolactone) (PCL) mats. This study focused on optimizing previously developed procedures for producing electrospun PCL/BG scaffolds, with particular attention to overcoming the intrinsically hydrophobic nature of electrospun PCL, which may limit scaffold functionality. To this end, a chemical surface modification treatment based on immersion in a sodium hydroxide (NaOH) solution was integrated into the fabrication process, and the properties of the chemically treated samples were compared with those of the untreated counterparts. Although the NaOH treatment significantly reduced the contact angle, the resulting values (an average reductionin contact angle of 26%) remained close to the hydrophobic/hydrophilic threshold, indicating improved wettability rather than a complete transition to a strongly hydrophilic surface. Furthermore, the adhesion and spreading of osteosarcoma cell lines (Saos-2) and of human dermal fibroblasts (HDFs) on the PCL/BG scaffolds were markedly enhanced by NaOH treatment. This work ultimately aims to contribute to the optimization of particle-loaded electrospun scaffolds, which could have interesting application potentials in hard and soft tissue engineering and tissue repair, aspects that deserve to be further explored.