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In this paper, a novel nanocomposite fluorescence detector that was synthesized from gold nanoclusters (AuNCs) and a ten-amino acid peptide CCYRGHDHCY was successfully generated for the determination of Allura red (AR) for the first time. Allura red can quench the fluorescence of AuNCs via the Forster resonance energy transfer (FRET) mechanism. Upon addition of Allura red, the red fluorescence intensity of peptide–AuNCs was dramatically quenched and had a linear relationship over the range of 2–90 μM of Allura red with high sensitivity. The results show that the detection limit is 0.667 μmol L−1 (S/N = 3), and the correlation coefficient of the standard curve is 0.998. Compared to the cumbersome and difficult operation of paper chromatography for the detection of Allura red, this method is simple to use and has a high recovery rate and good stability. Moreover, this proposed peptide–AuNCs fluorescence detector has the potential to be used for detecting Allura red in real samples with accurate results.

Superoxide anions (O2˙−) and hydrogen ions (H+) have attracted considerable attention in studies on cellular dysfunction. A newly synthesized reaction-based near-infrared imaging probe (IR-747-SAPH), which is composed of a superoxide anion responsive group and a H+ responsive group, exhibits high selectivity to O2˙− and H+ fluxes in vivo. The fluorescence intensity of IR-747-SAPH changes as O2˙− and H+ concentrations vary. IR-747-SAPH is characterized by sensitivity to changes in H+, high photostability, and strong near-infrared properties, including high temporal resolution, deep penetration, and low background interference. The probe also provides reliable near-infrared fluorescence signals that alter O2˙−and H+ levels in vivo. Therefore, IR-747-SAPH fluorescence imaging is a promising detection method for monitoring the changes in O2˙− and H+ in various biological environments.