ELECTROSPUN AND SOLVENT CASTED PCL-PLGA POROUS SCAFFOLDS EMBEDDED WITH INDUCED PLURIPOTENT STEM CELLS FOR TISSUE ENGINEERING APPLICATIONS: A PRELIMINARY STUDY

Tissue engineering (TE) is a specific branch of the much wider world of regenerative medicine. Precisely, TE is defined by the European Medicine Agency as “a medicine containing engineered cells or tissues, which is intended to regenerate, repair or replace a human tissue”. This goal can be achieved in many ways, one of which is to use cells placed on or within a matrix. In this context, the ambition and the challenge is to manufacture a scaffold able to replicate structurally, compositionally, and biologically, native tissues. Thus, to resemble the architecture of the native tissue both mechanically and architecturally, as well as to have the ability to support cell adhesion, proliferation, differentiation, and the production of extracellular matrix (ECM). When designing a scaffold for TE, it must be taken into consideration its biocompatibility, biodegradability, mechanical properties, and overall architecture. In this regard, the manufacturing technique and the material chosen for its production play a fundamental role in the final scaffold characteristics. As for the cell source, scaffolds are often used to culture cells in vitro and to be directly implanted in vivo. In both cases induced pluripotent stem cells (iPSCs) have been a wonderful and popular resource. iPSCs are under many aspects equivalent to embryonic stem cells (ESC), and have often been used in combination with 3-Dimensional (3-D) scaffolds. In fact, their lack of ethical issues, reduced immune rejection and the possibility to be pushed to differentiate towards many cell lines and tissues, have made them a favorite cell source. Our study aims to design, produce, and characterize 3-D scaffolds for TE applications made of Polylactic-co-glycolic acid (PLGA), Polycaprolactone (PCL) and their blends, trough electrospinning and solvent casting manufacturing techniques. Specifically, this preliminary study has the purpose to characterize these scaffolds from a physical, chemical, and biological point of view. To do so we performed a structural characterization of the scaffolds trough Scanning Electron Microscope (SEM) imaging, evaluated their tensile strength through tensile tests and the calculation of the Young Modulus (YM), assessed the surface hydrophobicity by performing contact angle measurements as well as deeper wettability evaluations with the water uptake analysis. Then, the most promising scaffolds were used to be seeded with iPSCs. Then, we performed an XTT Assay analysis to evaluate the cells metabolic activity, Reverse Transcription PCR (RT-PCR) and Real Time quantitative PCR (RT-qPCR) to evaluate cell pluripotency and integrin expression, as well as immunocytochemistry (ICC) and confocal microscope imaging to assess the pluripotency and general condition of the cells on the scaffolds. These analyses results brought us to conclude that while the scaffolds displayed different chemical and physical properties based on their composition and manufacturing technique, they also performed differently when embedded with iPSCs. Specifically, the solvent casted scaffolds resulted more suitable to be used with these cells. In conclusion, while the number of iPSCs present on the scaffold at the end of our analyses was indeed lower than the control, these cells still displayed a marked pluripotency and exhibited the expression of integrins. Thus suggesting promising results in future necessary analyses of process optimization and biological evaluation.