In vitro Characterization of Mesenchymal Stem Cell Biology on Biomimetic Poly-ε-caprolactone Nanofiber Scaffolding

Background: Myocardial infarction (MI) often results in permanent cardiac tissue necrosis and reduced heart functionality. Even with heart disease being the number one cause of death in the US, there are currently no effective methods of fully regenerating heart muscle post-myocardial infarction. Mesenchymal stem cells (MSCs) are a promising therapeutic option given their multi-potent nature and low host immune reaction. Bioengineered polymeric nanofiber scaffolds provide a structured growing environment and encourage cell elongation. Overview: This study characterizes MSC biology on poly-ε-caprolactone (PCL) nanofiber scaffolds in order to establish electrospun PCL nanofibers as a working biological scaffold for MSC growth, and to exhibit potential for further exploration of PCL nanofiber-grown MSC implants as a treatment for MI. Methods: MSCs were seeded on PCL scaffolds; cell viability was analyzed via XTT, cell apoptosis was analyzed via TUNEL/DAPI staining, and differentiation markers were analyzed via RT-PCR. Results: TUNEL/DAPI staining of confluent MSCs on PCL scaffolds showed low cell apoptosis over time. RT-PCR results showed no amplification of CD40 expression. Conclusion: PCL nanofibers seem to provide a suitable microenvironment for MSC seeding and proliferation. Further Direction: RT-PCR for CD80, CD86, COL1A1 (collagen), aSMA/Acta2 (smooth muscle), Flk1/VEGF2 (endothelial), Sparc (Osteonectin, osteogenic), Adipoq (Adiponectin, adipogenic), Agre-cano (chondrogenic).

Preparation of Silk Fibroin Nanofiber Scaffold and Its Application in Tendon-Bone Healing and Sports Rehabilitation

ABSTRACTIn this work, polylactic acid/polycaprolactone/silk fibroin (PLA/PCL/SF) nanofiber scaffolds with different mass ratios were prepared by electrospinning technology. The morphology and structure of the nanofiber scaffold were characterized with the scanning electron microscope (SEM), and its porosity and adsorption were tested using the Fourier transform infrared spectrometer (FTIR). 24 New Zealand white rabbits were rolled into control group (n = 8, with autologous tendons) and experimental group (n = 16) randomly. The PLA/PCL/SF nanofiber scaffolds were adopted to wrap autologous tendons to establish extra-articular models. Tendon-bone healing was evaluated six weeks after surgery through histological and biomechanical tests, and the related gene expressions in tissue cells were detected. It turned out that mass ratio of PLA/PCL and SF components had a considerable impact on the morphology of the nanofiber scaffold. The surface of nanofiber with a mass ratio of 3:1 was distributed with dense pores. As the content of SF increased, the porosity and adsorption of the nanofiber scaffold gradually decreased. Moreover, the experimental results suggested that the addition of SF improved the hydrophilicity of PLA/PCL/SF scaffold, which was beneficial to the adhesion and proliferation of NIH/3T3 (a mouse embryonic fibroblast cell line established by the National Institutes of Health (NIH)). In addition, histological observation results showed that the width of the tendon-bone interface (TBI) of rabbits in control group was still relatively large at the 6th week after the surgery, with poor healing effect and disordered collagen arrangement. The widths of the TBI of the material group and rehabilitation group were substantially narrower relative to that in control group, and the collagen was arranged regularly. It was suggested that the healing effects between tendon and bone in material group and rehabilitation group were accelerated, and the effect in the rehabilitation group was superior to that of material group, indicating that rehabilitation exercise could organize the negative effects of training in postoperative rehabilitation training and promote the healing between tendons and bones.