Hydrogels are suitable for osteochondral defect regeneration as they mimic the viscoelastic environment of cartilage. However, their biomechanical properties are not sufficient to withstand high mechanical forces. Therefore, we have prepared electrospun poly-ε-caprolactone-chitosan (PCL-chit) and poly(ethylene oxide)-chitosan (PEO-chit) nanofibers, and FTIR analysis confirmed successful blending of chitosan with other polymers. The biocompatibility of PCL-chit and PEO-chit scaffolds was tested; fibrochondrocytes and chondrocytes seeded on PCL-chit showed superior metabolic activity. The PCL-chit nanofibers were cryogenically grinded into microparticles (mean size of about 500 µm) and further modified by polyethylene glycol-biotin in order to bind the anti-CD44 antibody, a glycoprotein interacting with hyaluronic acid (PCL-chit-PEGb-antiCD44). The PCL-chit or PCL-chit-PEGb-antiCD44 microparticles were mixed with a composite gel (collagen/fibrin/platelet rich plasma) to improve its biomechanical properties. The storage modulus was higher in the composite gel with microparticles compared to fibrin. The Eloss of the composite gel and fibrin was higher than that of the composite gel with microparticles. The composite gel either with or without microparticles was further tested in vivo in a model of osteochondral defects in rabbits. PCL-chit-PEGb-antiCD44 significantly enhanced osteogenic regeneration, mainly by desmogenous ossification, but decreased chondrogenic differentiation in the defects. PCL-chit-PEGb showed a more homogeneous distribution of hyaline cartilage and enhanced hyaline cartilage differentiation.

• Keywords
• CD44 antibody, cartilage, collagen, fibrin, microparticles, poly-ε-caprolactone,
• Publication type
• Journal Article MeSH

Fibrin plays an important role during wound healing and skin regeneration. It is often applied in clinical practice for treatment of skin injuries or as a component of skin substitutes. We prepared electrospun nanofibrous membranes made from poly(l-lactide) modified with a thin fibrin nanocoating. Fibrin surrounded the individual fibers in the membrane and also formed a thin fibrous mesh on several places on the membrane surface. The cell-free fibrin nanocoating remained stable in the cell culture medium for 14 days and did not change its morphology. On membranes populated with human dermal fibroblasts, the rate of fibrin degradation correlated with the degree of cell proliferation. The cell spreading, mitochondrial activity, and cell population density were significantly higher on membranes coated with fibrin than on nonmodified membranes, and this cell performance was further improved by the addition of ascorbic acid in the cell culture medium. Similarly, fibrin stimulated the expression and synthesis of collagen I in human dermal fibroblasts, and this effect was further enhanced by ascorbic acid. The expression of beta1-integrins was also improved by fibrin, and on pure polylactide membranes, it was slightly enhanced by ascorbic acid. In addition, ascorbic acid promoted deposition of collagen I in the form of a fibrous extracellular matrix. Thus, the combination of nanofibrous membranes with a fibrin nanocoating and ascorbic acid seems to be particularly advantageous for skin tissue engineering.

• Keywords
• ascorbic acid, beta1-integrins, collagen I synthesis, electrospun nanofibers, fibrin, fibroblasts, nanocoating, nanomedicine, nanotechnology, skin tissue engineering,
• MeSH
• Cell Differentiation MeSH
• Electrochemistry methods   MeSH
• Extracellular Matrix metabolism   MeSH
• Fibrin chemistry   metabolism   MeSH
• Fibroblasts cytology   metabolism   MeSH
• Fluorescent Antibody Technique MeSH
• Immunoenzyme Techniques MeSH
• Collagen genetics   metabolism   MeSH
• Cells, Cultured MeSH
• Skin cytology   metabolism   MeSH
• Real-Time Polymerase Chain Reaction MeSH
• Humans MeSH
• RNA, Messenger genetics   MeSH
• Nanofibers chemistry   MeSH
• Polyesters chemistry   MeSH
• Reverse Transcriptase Polymerase Chain Reaction MeSH
• Cell Proliferation MeSH
• Regeneration physiology   MeSH
• Tissue Engineering methods   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Fibrin MeSH
• Collagen MeSH
• RNA, Messenger MeSH
• poly(lactide) MeSH Browser
• Polyesters MeSH