Nitrogen-Vacancy Magnetic Relaxometry of Nanoclustered Cytochrome C Proteins
Suvechhya Lamichhane, Rupak Timalsina, Cody Schultz, Ilja Fescenko, Kapildeb Ambal, S. H. Liou, Rebecca Y. Lai, Abdelghani Laraoui
Abstract
Nitrogen-vacancy (NV) magnetometry offers an alternative tool to detect paramagnetic centers in cells with a favorable combination of magnetic sensitivity and spatial resolution. Here, we employ NV magnetic relaxometry to detect cytochrome C (Cyt-C) nanoclusters. Cyt-C is a water-soluble protein that plays a vital role in the electron transport chain of mitochondria. Under ambient conditions, the heme group in Cyt-C remains in the Fe 3+ state, which is paramagnetic. We vary the concentration of Cyt-C from 6 to 54 μM and observe a reduction of the NV spin–lattice relaxation time ( T 1 ) from 1.2 ms to 150 μs, which is attributed to the spin noise originating from the Fe 3+ spins. NV T 1 imaging of Cyt-C drop-casted on a nanostructured diamond chip allows us to detect the relaxation rates from the adsorbed Fe 3+ within Cyt-C.