Multiplexing Quantum Biosensing with DNA-Functionalized Diamond Surfaces

Ignacio Chi-Durán The University of Chicago

Nitrogen-vacancy (NV) centers in diamonds offer unprecedented sensitivity in detecting magnetic fields and other physical quantities, making them highly promising for diagnostic assays [1]. Over the past decades, sensor technology has trended towards miniaturization, parallelization in arrays, and reduced limits of detection. As a proof of concept, we fabricated an array of 49 distinct DNA spots on a 2x2 mm2 diamond surface to detect binding between complementary DNA strands (Figure 1a). Our optimized surface functionalization method immobilized DNA strands at a density of 0.01 DNA/nm2, with less than 10 nm separation between the DNA and the quantum sensor layer [2]. Using T1 relaxometry, we detected DNA binding by displacing a partially complementary Gd3+- labeled strand. The reduction in magnetic noise near the NV center, indicated by the recovery of NV T1 time, confirmed the specific binding of DNA strands (Figure 1b). Our results demonstrate that the hybridization efficiency of our DNA microarray on the diamond surface is comparable to those reported in the literature. Combining this multiplexed sensing platform with T1-based imaging microscopy techniques presents a convenient route to developing a high-throughput diagnostic quantum sensing device for complex biological samples.

[1] Aslam, Nabeel, et al. “Quantum sensors for biomedical applications.” Nature Reviews Physics 5.3 (2023): 157-169.

[2] Xie, Mouzhe, et al. “Biocompatible surface functionalization architecture for a diamond quantum sensor.” Proceedings of the National Academy of Sciences 119.8 (2022): e2114186119.