Figure 3
From: A protonic biotransducer controlling mitochondrial ATP synthesis
pH control in mitochondrial matrix with pH modulation. (a) Schematic of the pH modulator integrated with BCECF-labeled mitochondria. BCECF dye is a hydrophilic, dual-excitation ratiometric pH indicator that is trapped in the matrix and indicates the local pH through a pH-dependent ratio of emitted fluorescence at excitation wavelengths of 480 and 405 nm (F480/F405 ratio). (b,c) Transmittance and fluorescence images of the adsorbed mitochondria on the comb SPA microelectrode fabricated on a glass substrate. Black lines are where the SPA microelectrodes block the light transmission. White lines are the exposed glass substrate where adsorbed mitochondria can be observed. Scale bar: 5 μm. (d) The matrix pH fluctuated in response to doping and dedoping of H+ from SPA microelectrode. At t = 0, pH was 7.7. Vr pulse for H+ doping was applied for 5 min at t = 0, 10 and 20 min. Vo pulse was applied at t = 5, 15 and 25 min. The pH in 19 individual mitochondria was monitored with time. *P < 0.05. (e) Pseudo color images of the matrix pH estimated from the BCECF ratio at t = 0, 5 10, 15, 20 and 25 min. Scale bar: 2 μm.
