Noninvasive measurement of viable cell number in tissue-engineered constructs in vitro, using ¹H nuclear magnetic resonance spectroscopy

Noninvasive monitoring of tissue-engineered constructs is of critical importance for accurate characterization of constructs and their remodeling in vitro and in vivo. This study investigated the utility of ¹H NMR spectroscopy to noninvasively quantify viable cell number in tissue-engineered substitutes in vitro. Agarose disk-shaped constructs containing βTC3 cells were employed as the model tissue-engineered system. Two construct prototypes containing different initial cell numbers were monitored by localized, water-suppressed ¹H NMR spectroscopy over the course of 13 days. ¹H NMR measurements of the total choline resonance at 3.2 ppm were compared with results from the traditional cell viability assay MTT and with insulin secretion rates. Results show a strong linear correlation between total choline and MTT (R² = 0.86), and between total choline and insulin secretion rate (R² = 0.90). Overall, this study found noninvasive measurement of total choline to be an accurate and nondestructive assay for monitoring viable βTC3 cell numbers in tissue-engineered constructs. The applicability of this method to in vivo monitoring is also discussed.