Development of hybrid bioactive nanofibers composed of star Poly(lactic acid) and gelatin by sol-gel crosslinking during the electrospinning process.

The design of a biomimetic scaffold is a major challenge in tissue engineering to promote tissue reconstruction. The use of synthetic polymer nanofibers is widely described as they provide biocompatible matrices whose topography mimics natural extracellular matrix (ECM). To closely match the biochemical composition of the ECM, bioactive molecules such as gelatin are added to the nanofibers to enhance cell adhesion and proliferation. To overcome the rapid solubilization of gelatin in biological fluids and to allow a lasting biological effect, the covalent crosslinking of this macromolecule in the network is crucial. The sol-gel route offers the possibility of gentle crosslinking during shaping but is rarely combined with electrospinning. In this study, we present the creation of Poly(lactic acid)/Gelatin hybrid nanofibers by sol-gel route during electrospinning. To enable sol-gel crosslinking, we synthesized star-shaped PLA and functionalized it with silane groups; then we functionalized gelatin with the same groups for their subsequent reaction with the polymer and thus the creation of the hybrid nanonetwork. We evaluated the impact of the presence of gelatin in Poly(lactic acid)/Gelatin hybrid nanofibers at different percentages on the mechanical properties, nanonetwork crosslinking, degradation and biological properties of the hybrid nanofibers. The addition of gelatin modulated nanonetwork crosslinking that impacted the stiffness of the nanofibers, resulting in softer materials for the cells. Moreover, these hybrid nanofibers also showed a significant improvement in fibroblast proliferation and present a degradation rate suitable for tissue reconstruction. Finally, the bioactive hybrid nanofibers possess versatile properties, interesting for various potential applications in tissue reconstruction.

Creation of a Stable Nanofibrillar Scaffold Composed of Star-Shaped PLA Network Using Sol-Gel Process during Electrospinning.

PLA nanofibers are of great interest in tissue engineering due to their biocompatibility and morphology; moreover, their physical properties can be tailored for long-lasting applications. One of the common and efficient methods to improve polymer properties and slow down their degradation is sol-gel covalent crosslinking. However, this method usually results in the formation of gels or films, which undervalues the advantages of nanofibers. Here, we describe a dual process sol-gel/electrospinning to improve the mechanical properties and stabilize the degradation of PLA scaffolds. For this purpose, we synthesized star-shaped PLAs and functionalized them with triethoxysilylpropyl groups (StarPLA-PTES) to covalently react during nanofibers formation. To achieve this, we evaluated the use of (1) a polymer diluent and (2) different molecular weights of StarPLA on electrospinnability, StarPLA-PTES condensation time and crosslinking efficiency. Our results show that the diluent allowed the fiber formation and reduced the condensation time, while the addition of low-molecular-weight StarPLA-PTES improved the crosslinking degree, resulting in stable matrices even after 6 months of degradation. Additionally, these materials showed biocompatibility and allowed the proliferation of fibroblasts. Overall, these results open the door to the fabrication of scaffolds with enhanced stability and prospective long-term applications.