Real-time label-free monitoring of adipose-derived stem cell differentiation with electric cell-substrate impedance sensing

TLDR

Real‑time, label‑free monitoring of stem‑cell differentiation is essential for scaling cell‑therapy production while preserving therapeutic potential. The authors cultured adipose‑derived stem cells on multielectrode arrays and recorded complex impedance (Z*) every 180 s for 17 days across 62.5–64 kHz with an ECIS Zθ instrument. Distinct impedance trajectories for osteogenic versus adipogenic differentiation emerged within 12 h, with barrier resistance and membrane capacitance changes enabling early lineage discrimination and demonstrating that impedance sensing can quantitatively track adult stem‑cell differentiation in real time.

Abstract

Real-time monitoring of stem cells (SCs) differentiation will be critical to scale-up SC technologies, while label-free techniques will be desirable to quality-control SCs without precluding their therapeutic potential. We cultured adipose-derived stem cells (ADSCs) on top of multielectrode arrays and measured variations in the complex impedance Z* throughout induction of ADSCs toward osteoblasts and adipocytes. Z* was measured up to 17 d, every 180 s, over a 62.5–64kHz frequency range with an ECIS Zθ instrument. We found that osteogenesis and adipogenesis were characterized by distinct Z* time-courses. Significant differences were found ( P = 0.007) as soon as 12 h post induction. An increase in the barrier resistance (Rb) up to 1.7 ohm·cm 2 was associated with early osteo-induction, whereas Rb peaked at 0.63 ohm·cm 2 for adipo-induced cells before falling to zero at t = 129 h. Dissimilarities in Z* throughout early induction (<24 h) were essentially attributed to variations in the cell-substrate parameter α. Four days after induction, cell membrane capacitance (Cm) of osteo-induced cells (Cm = 1.72 ± 0.10 μF/cm 2 ) was significantly different from that of adipo-induced cells (Cm = 2.25 ± 0.27 μF/cm 2 ), indicating that Cm could be used as an early marker of differentiation. Finally, we demonstrated long-term monitoring and measured a shift in the complex plane in the middle frequency range (1 kHz to 8 kHz) between early ( t = 100 h) and late induction ( t = 380 h). This study demonstrated that the osteoblast and adipocyte lineages have distinct dielectric properties and that such differences can be used to perform real-time label-free quantitative monitoring of adult stem cell differentiation with impedance sensing.