On-Chip NADH\nDetection in Multicellular Models Using\nan AlGaN/GaN Photodetector Array with Enhanced Sensitivity

Nicotinamide adenine dinucleotide (NAD) is a pivotal\ncoenzyme,\nexisting in its oxidized form (NAD<sup>+</sup>) and reduced form (NADH).\nBoth are essential in cellular redox reactions and are implicated\nin energy production and cancer. Current NADH detection methods often\ninvolve complex optical measurements. We propose a miniaturized, on-chip\nphotoelectric sensor array using AlGaN/GaN two-dimensional electron\ngas (2DEG) photodetectors for NADH quantification. The device exhibits\nan ultralow dark current and ultrahigh UV light responsivity, enabling\nsensitive NADH detection. By exploiting the absorbance disparity between\nNADH and NAD<sup>+</sup>, our sensor achieves rapid, sensitive detection,\nsurpassing commercial assays. It effectively detects NADH levels in\n3D multicellular models, promising cancer screening and monitoring.\nThis sensor platform offers a significant advancement in NADH quantification,\nwith the potential for high-throughput testing and point-of-care diagnostics.\nOur study presents an efficient approach for NADH sensing, addressing\nthe need for rapid and sensitive detection methods in biomedical research\nand clinical practice.