Proceedings Article | 14 March 2018
KEYWORDS: Tissue optics, Diffuse reflectance spectroscopy, In vitro testing, In vivo imaging, Manufacturing, Microscopy, Tissue engineering, Regenerative medicine, Light wave propagation, Diagnostics
Quantitative diffuse reflectance spectroscopy was developed for label-free, noninvasive, and real-time assessment of implanted tissue-engineered devices manufactured from primary human oral keratinocytes. Studies have shown that implanting manufactured tissue-engineered devices developed from a patient’s own cells have healed oral wounds up to twice as fast as the current clinical standard-of-care. Regulatory approval for such cell-based combinational devices requires reliable methods to assess pre-implantation construct viability in vitro and post-implantation construct success in vivo. Unfortunately, current evaluation methods are limited, either being qualitative, destructive, time-consuming, unreliable, lacking in spatial information, or a combination thereof. For example, we previously characterized the viability of such tissue-engineered construct in vitro with nonlinear optical microscopy [5]. While the microscopy successfully characterized construct viability in vitro, limitations persist about its adaptability and suitability for in vivo use, including high cost, slow measurement time, and high level of operator expertise required for accurate, repeatable measurements. However, there remains no obvious path to determine which devices are most likely to succeed after implantation and what markers may predict successful implantation. To address this need, we assessed devices implanted in a murine model for either one or three weeks with diffuse reflectance spectroscopy to evaluate construct success in situ using optical absorption and scattering (assessing revascularization, cellular density, and cell layer thickness) and compared with destructive histology. Quantitative diffuse reflectance spectroscopy is a promising, clinically-compatible technology for rapid, noninvasive, and localized tissue assessment to characterize tissue-engineered construct success in vivo.
