Department of Electronics, University of Glasgow, UK.
Electrophoresis. 2010 Apr;31(8):1405-13. doi: 10.1002/elps.200900579.
An array of PDMS microchambers was aligned to an array of sensor electrodes and stimulating microelectrodes, which was used for the electrochemical monitoring of the metabolic activity of single isolated adult ventricular myocytes inside the chamber array, stimulated within a transient electric field. The effect of the accumulation of metabolic byproducts in the limited extracellular volume of the picolitre chambers was demonstrated by measuring single muscle cell contraction optically, while concomitant changes in intracellular calcium transients and pH were recorded independently using fluorescent indicator dyes. Both the amplitude of the cell shortening and the magnitude of the intracellular calcium transients decreased over time and both nearly ceased after 20 min of continuous stimulation in the limited extracellullar volume. The intracellular pH decreased gradually during 20 min of continuous stimulation after which a dramatic pH drop was observed, indicating the breakdown of the intracellular buffering capacity. After continuous stimulation, intracellular lactate was released into the microchamber through cell electroporation and was detected electrochemically at a lactate microbiosensor, within the chamber. A mitochondrial uncoupler was used to mimic ischaemia and thus to enhance the cellular content of lactate. Under these circumstances, intracellular lactate concentrations were found to have risen to approximately 15 mM. This array system has the potential of simultaneous electrochemical and optical monitoring of extracellular and intracellular metabolites from single beating heart cells at a controlled metabolic state.
PDMS 微腔阵列与传感器电极和刺激微电极对齐，用于在瞬变电场中刺激腔阵列内的单个分离成年心室肌细胞的代谢活性的电化学监测。通过光学测量单个肌肉细胞的收缩来证明代谢副产物在皮升腔有限的细胞外体积中的积累的影响，同时使用荧光指示剂染料独立记录细胞内钙瞬变和 pH 的伴随变化。细胞缩短的幅度和细胞内钙瞬变的幅度随时间推移而降低，并且在有限的细胞外体积中连续刺激 20 分钟后几乎停止。在连续刺激 20 分钟期间，细胞内 pH 值逐渐下降，随后观察到 pH 值急剧下降，表明细胞内缓冲能力的崩溃。连续刺激后，细胞内乳酸通过细胞电穿孔释放到微腔中，并在腔内的乳酸微生物传感器中电化学检测到。使用线粒体解偶联剂模拟缺血，从而提高细胞内乳酸含量。在这些情况下，发现细胞内乳酸浓度升高到约 15mM。该阵列系统具有在受控代谢状态下同时电化学和光学监测单个搏动心脏细胞的细胞外和细胞内代谢物的潜力。
