Nitrogen-Vacancy Magnetic Relaxometry of Nanoclustered Cytochrome C Proteins.

Lamichhane, Suvechhya; Timalsina, Rupak; Schultz, Cody; Fescenko, Ilja; Ambal, Kapildeb; Liou, Sy-Hwang; Lai, Rebecca Y; Laraoui, Abdelghani · Nano Lett · 2024

basic_science · Level V

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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<sup>3+</sup> 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 (<i>T</i><sub>1</sub>) from 1.2 ms to 150 μs, which is attributed to the spin noise originating from the Fe<sup>3+</sup> spins. NV <i>T</i><sub>1</sub> imaging of Cyt-C drop-casted on a nanostructured diamond chip allows us to detect the relaxation rates from the adsorbed Fe<sup>3+</sup> within Cyt-C.

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