Near-infrared fluorescent probe featuring a large Stokes shift for sensitive detection of NADH in diabetic models

Document Type

Article

Publication Date

12-1-2025

Abstract

Nicotinamide adenine dinucleotide (NADH) is a key metabolic and redox signaling molecule closely associated with metabolic disorders, including diabetes. Developing effective methods for monitoring NADH levels in cells and in vivo is critical for advancing early diagnostic strategies for such diseases. In this work, we report two novel fluorescent probes (A and B) for NADH detection, based on the conjugation of phenanthridinium and 1-methylquinolinium via a double bond. Upon reaction with NADH, the 1-methylquinolinium moiety undergoes specific reduction to form an electron-donating 2-hydroquinoline group, which initiates an intramolecular charge transfer (ICT) process, leading to significant fluorescence enhancement. Compared to Probe A, Probe B incorporates an additional N,N-diethylamine group on the phenanthridinium unit, acting as a second electron donor. This modification results in markedly improved sensing performance, including a rapid response time of 20 min, near-infrared fluorescence enhancement with large Stokes shift (130 nm), the lower detection limit, and excellent selectivity against interfering species. Probe B was effectively employed for visualization the NADH levels in both endogenous and exogenous cellular environments, as well as in diabetic cells. Furthermore, in vivo imaging studies in diabetic mice demonstrated its capability to monitor NADH fluctuations under pathological conditions. This study not only provides a novel design strategy for developing NADH fluorescent probes with large Stokes shifts, but also highlights the potential of Probe B as a powerful near-infrared fluorescent tool for real-time NADH imaging, offering promising applications in the early diagnosis and monitoring of diabetes.

Publication Title

Sensors and Actuators B Chemical

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