Functional and structural optimization of electrospun scaffolds for the regeneration of ligaments and tendons

Tendons and ligaments are the connective tissues between muscles and bones that provide stability and support to joints. Current treatments for injuries to these tissues often have limited repair and, for the most part, do not recover full function, resulting in symptoms such as chronic pain, instability and impaired function. To address these limitations, electrospinning is a promising and versatile technique to produce nanofibrous scaffolds that mimic the natural extracellular matrix and biomechanical properties of tendons and ligaments. The specific objective of this research work was to optimise the structure and function of electrospun scaffolds for tendon and ligament regeneration. Two critical areas of scaffold optimisation are examined in this research work: the effects of gamma-ray sterilisation on scaffold properties and a novel approach to gradually mineralise an electrospun hierarchical bundle scaffold for enthesis regeneration. Gamma-ray radiations are one of the most suitable treatments to sterilise electrospun devices, but the amount of irradiation has to be carefully chosen to avoid polymeric nanofiber degradation and changes in biomaterial properties. The first study in the Thesis aimed to investigate the effects of gamma-irradiation on electrospun nanofibrous bundles of aligned nanofibers inspired by tendon/ligament fascicles which were irradiated at three different doses (5, 10, and 25 kGy). The effects of the irradiation were investigated by analysing the scaffold’s morphology, physicochemical properties and mechanical properties to identify the most suitable range of radiation that least affected scaffolds’ structure and mechanics, while granting effective sterilisation. The second study was aimed at gradient mineralisation of the fascicle-inspired electrospun bundles for enthesis regeneration. An alternative soaking method was used to deposit minerals in a gradient fashion to mimic the mineral gradient found in native entheses. Morphological, physicochemical and mechanical characterisation of these mineralised bundles showed that they were ideal candidates for repair of tendon and ligament enthesis.