Nanochannel Trap Arrays for Monitoring Single Mitochondrion Behavior

We present a nanofluidic device for trapping and fluorescence imaging of individual isolated mitochondria. The device consists of an array of 10 parallel nanochannels fabricated out of PDMS each with a cross section of 500 nm x 2 µm. Mitochondria are isolated from a human cervical cancer cell line (HeLa). Respiration buffer containing the mitochondria is pumped into the device using a syringe pump. Due to the small height of the trap channels individual mitochondria get immobilized one by one along the channels. Time lapsed fluorescence microscopy of JC-1 and TMRM stained mitochondria reveals that trapped mitochondria maintain their membrane potential. The effect of adding substrates and calcium on the membrane potential is studied and the results indicate that mitochondria remain vital and functional in this trapped state. Flickering of membrane potential in some substrate fed mitochondria is observed.