Nano/micro-structured poly(ϵ-caprolactone)/gelatin nanofibers with biomimetically-grown hydroxyapatite spherules: High protein adsorption, controlled protein delivery and sustained bioactive ions release designed as a multifunctional bone regenerative membrane

Bioactive and biodegradable fibrous membranes are highly attractive for periodontal bone regeneration. Herein, we demonstrate a new approach for fabrication of a novel nano/micro-structured fibrous membrane made of biodegradable poly(ϵ-caprolactone)/gelatin (PCL/GEL) nanofibers and biomemtically-grown hydroxyapatite spherules (HAs). The proposed approach includes electrospinning fabrication of PCL/GEL nanofibers containing nanobioglass (NBG) agglomerates and their biomimetic transformation into HAs. The NBG agglomerates (~1.9 μm in diameter) enabled the growth of biomimetic HAs (~4 μm in diameter) around the PCL/GEL nanofibers and generated a unique nano/micro-structure. Interestingly, the biomimetically-grown HAs imparted the PCL/GEL-HAs nanofibrous membrane with several remarkable properties including nano/micro-topography, bone-mimetic composition (Ca/P = 1.60), large specific surface area (~31 m2/g), high protein adsorption capacity (~157 μg protein/mg membrane) and controlled protein delivery with zero-order release kinetics; along with sustained release of therapeutic ions (Ca2+ ~ 37 ppm, PO 4 3− ~ 24 ppm, and SiO 4 4− ~ 61 ppm). Furthermore, the PCL/GEL-HAs membrane exhibited enhanced wettability, good biodegradability and adequate mechanical properties. Collectively, the PCL/GEL-HAs demonstrated unique properties and it can be considered as a novel multifunctional bioactive/biodegradable membrane for periodontal bone regeneration. [Display omitted] • Novel nano/micro-structured PCL/GEL-HAs fibrous membrane was prepared by a two-step process. • The presence of HA spherules resulted in a high specific surface area and a high protein adsorption capacity. • PCL/GEL-HAs membrane releases bioactive ions including Ca2+, PO 4 3− and SiO 4 4−. • PCL/GEL-HAs membrane releases cytochrome c with zero-order release kinetics. • PCL/GEL-HAs is considered as a novel multifunctional bioactive/biodegradable membrane for periodontal bone regeneration. [ABSTRACT FROM AUTHOR]