Adult tendons/ligaments have low oxygen and nutrient requirements, low cell density and poor regenerative capacity and often surgical intervention is needed to promote healing of these tissues. Delivery of soluble growth factors to these tissues is known to promote and enhance the healing process, however this is accomplished with supraphysiological concentrations of growth factors. One way to overcome this problem is to immobilize the growth factors in biomaterials, however very little research exploiting this strategy has been done for tendons and ligaments. Here we present for the first time a non-covalent method for the delivery of growth factors to promote and enhance the healing process of these tissues. In this work we functionalized polycaprolactone with synthetic peptides that display affinity for specific growth factors. Growth factor binding peptides were synthetized using FMOC-Solid Phase Peptide Synthesis and purified using standard HPLC methods. We demonstrated that it is possible to specifically immobilize TGF-β1, BMP-2 and VEGF on PCL functionalized with the respective affinity binding peptide and confirmed this by antibody staining and ELISAs. Our data shows that the immobilized growth factors retained their bioactivity and activated the respective signaling pathways. Immobilized TGF-β1 induced Smad2/3 translocation to the nucleus, activation of tendon/ligaments related genes and led to a 2,5 fold increase in collagen protein content in human Hamstring cells while Immobilized BMP-2 activated Smad1/5/8 phosphorylation and induced ALP expression in C2C12 in vitro. Further experiments will be conducted in vivo and with combination of different growth factor binding peptides within the same material.
|Journal||Tissue engineering. Part A|
|Publication status||Published - 2015|
|Event||2015 4th TERMIS World Congress, 8-11 September 2015, Boston, Massachusetts, USA - Boston, United States|
Duration: 8 Sep 2015 → 11 Sep 2015