Quantitative diffuse reflectance spectroscopy (DRS) was developed for label-free, noninvasive, and real-time assessment of implanted tissue-engineered devices manufactured from primary human oral keratinocytes (six batches in two 5-patient cohorts). Constructs were implanted in a murine model for 1 and 3 weeks. DRS evaluated construct success in situ using optical absorption (hemoglobin concentration and oxygenation, attributed to revascularization) and optical scattering (attributed to cellular density and layer thickness). Destructive pre- and postimplantation histology distinguished experimental control from stressed constructs, whereas noninvasive preimplantation measures of keratinocyte glucose consumption and residual glucose in spent culture media did not. In constructs implanted for 1 week, DRS distinguished control due to stressed and compromised from healthy constructs. In constructs implanted for 3 weeks, DRS identified constructs with higher postimplantation success. These results suggest that quantitative DRS is a promising, clinically compatible technology for rapid, noninvasive, and localized tissue assessment to characterize tissue-engineered construct success in vivo. Impact statement Despite the recent advance in tissue engineering and regenerative medicine, there is still a lack of nondestructive tools to longitudinally monitor the implanted tissue-engineered devices. In this study, we demonstrate the potential of quantitative diffuse reflectance spectroscopy as a clinically viable technique for noninvasive, label-free, and rapid characterization of graft success in situ.
Keywords: AlloDerm; EVPOME; diffuse reflectance spectroscopy; light propagation in tissues; optical diagnostics for medicine; tissue diagnostics; tissue engineering and regenerative medicine.