Optimized electro- and wet-spinning techniques for the production of polymeric fibrous scaffolds loaded with bisphosphonate and hydroxyapatite

This research activity was aimed at the development of composite bioactive scaffolds made of biodegradable three-arm branched-star poly(epsilon-caprolactone) (*PCL), hydroxyapatite nanoparticles (HNPs) and clodronate (CD), a bisphosphonate that has demonstrated efficacy in the treatment of various bone diseases and as an anti-inflammatory drug. During the experimental work, the processing conditions for the fabrication of fibrous meshes, by either electrospinning or wet-spinning, were optimized. Stemming from a previous research activity on electrospinning of *PCL, *PCL/HNPs 3D meshes were developed, evaluating the influence of fabrication parameters on the fibres' morphology. By exploiting the binding affinity of bisphosphonates for hydroxyapatite, a methodology was set up for obtaining a physical linkage between CD and HNPs, with the aim of having a dual bioactive system loaded into *PCL fibrous mats. Fibres loaded with either CD or CD-HNP particles were thus produced and analysed by scanning electron microscopy for their morphology and by energy dispersive X-ray spectroscopy for their elemental composition.