Quantitative estimates of vascularity in a collagen-based cell scaffold containing basic fibroblast growth factor by non-invasive near-infrared spectroscopy for regenerative medicine

Successful tissue regeneration required both cells with high proliferative and differentiation potential and an environment permissive for regeneration. These conditions can be achieved by providing cell scaffolds and growth factors that induce angiogenesis and cell proliferation. Angiogenenis within cell scaffolds is typically determined by histological examination with immunohistochemical markers for endothelium. Unfortunately, this approach requires removal of tissue and the scaffold In this study, we examined the hemoglobin content of implanted collagen-based cell scaffolds containing basic fibroblast growth factor (bFGF) in vivo by non-invasive near infrared spectroscopy (NIRS). We also compared the hemoglobin levels measured by MRS to the hemoglobin content measured with a conventional biological assay. Non-invasive NIRS recordings were performed with a custom-built near-infrared spectrometer using light guide-coupled reflectance measurements. MRS recordings revealed that absorbance increased after implantation of collagen scaffolds containing bFGF. This result correlated (R-2=0.93) with our subsequent conventional hemoglobin assay. The MRS technique provides a non-invasive method for measuring the degree of vascularization in cell scaffolds. This technique may be advantageous for monitoring angiogenesis within different cell scaffolds, a prerequisite for effective tissue regeneration.