A Cellular No Sensor Based on Aggregation-Induced Electrochemiluminescence and Photoelectron Transfer of a Novel Ruthenium(Ii) Complex

Abstract

Herein, we proposed a dual amplification strategy based on aggregation-induced and photoelectron transfer (PET) inhibition using a designed ruthenium-based complex for ultra-sensitive detection of nitric oxide (NO). [Ru(phen)2(DA-phen)]2+ (DA-phen: 5,6-diamino-1,10-phenanthroline) as a novel ruthenium(II) complex, was synthesized that uses the O-diaminophenyl group for specific recognition of NO. In the first step, the 1,10-phenanthroline groups function as the aggregation part. Increasing the volume fraction of a poor solution (H2O: fw, v%) in the DMSO mixture system yielded an increase in the fluorescence (FL) intensities by 3-fold when compared with the FL in pure DMSO. The second step involves a PET process. The complex reacting with NO under aerobic conditions to afford its triazole derivative in physiological pH aqueous media, [Ru(phen)2(5,6-triazole-phen)]2+, inhibited the electron transfer process, yielding a remarkable further increase in the FL and ECL efficiencies of the Ru(II) complex. The FL and ECL intensities were 51- and 86-fold higher in the presence of NO, respectively. This dual amplification strategy enabled the sensitive detection of NO from 1.8 × 10–10 to 1.8 × 10–4 M with a detection limit of 60 pM (S/N = 3) and good anti-interference. Furthermore, this assay is suitable for selective NO detection in cells.

Keywords: Aggregation, electrochemiluminescence (ECL), photoelectron transfer (PET), ruthenium (II) complexes, nitric oxide