Scanning microwave microscopy of vital mitochondria in respiration buffer

Jinfeng Li (1) , Zahra Nemati , Kamel Haddadi (2, 3) , Douglas C. Wallace , Peter J. Burke

1 Supply Chain Management and Logistics Research
2 IEMN - Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520
3 CSAM - IEMN - Circuits Systèmes Applications des Micro-ondes - IEMN

We demonstrate imaging using scanning microwave microscopy (SMM) of vital mitochondria in respiration buffer. The mitochondria are isolated from cultured HeLa cells and tethered to a solid graphene support. The mitochondria are kept vital (alive) using a respiration buffer, which provides nutrients to sustain the Krebs cycle. We verify that the mitochondria are "alive" by measuring the membrane potential using a voltage sensitive fluorescent dye (TMRE). The organelles are measured capacitively at 7 GHz. Several technical advances are demonstrated which enable this work: 1) The SMM operates in an electrophysiologically relevant liquid (hence conducting) environment; 2) The SMM operates in tapping mode, averaging the microwave reflection measurement over many tapping periods; 3) A tuned reflectometer enables increased sensitivity; 4) Variable frequencies up to 18 GHz are used; 5) In contrast with traditional matching/resonant methods that exhibit high quality factor that fail in the presence of liquids, interferometric/tuned reflectometer gives the possibility to adjust the quality factor or sensitivity even in the presence of the liquid.

Domaines: Sciences de l'ingénieur [physics]

Jinfeng Li, Zahra Nemati, Kamel Haddadi, Douglas C. Wallace, Peter J. Burke. Scanning microwave microscopy of vital mitochondria in respiration buffer. IEEE/MTT-S International Microwave Symposium, IMS 2018, Jun 2018, Philadelphia, PA, United States. pp.115-118, ⟨10.1109/MWSYM.2018.8439645⟩. ⟨hal-03224648⟩