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The present manuscript reports a lucrative design of a colorimetric and ratiometric chemodosimeter, 9-O-(2,4-dinitrobenzenesulfonyl)berberrubine (BER-S), with excellent water solubility for the superb selective detection of sulfides through a color alteration from yellow to red with a good limit of detection (LOD) of 56 nM in CP buffer solution (10 mM, pH 7.2). Interestingly, this work also includes a smart “turn-on” emission probe (BER-S/DNA complex) showing good linearity with an excellent LOD of 46 nM for recognizing sulfide anions. The probes, BER-S, and BER-S/DNA complex, displayed no interfering effect by other analytes or sulfur-containing inorganic compounds, like thiols. Characterization was carried out using IR, HRMS, and DFT for the BER-S probe, and time-resolved fluorescence lifetime measurement and fluorescence titration for the BER-S/DNA complex probe for elucidating their sensing mechanism. The detection of S2− in waste, tap, and drinking water by BER-S indicated its potential application in real sample analysis, while concentration variant cell imaging experiments (naked-eye red fluorescence) verified its cell-membrane permeability and capability for S2− imaging in living cells. This reaction-based sensing strategy in the presence of DNA may provide a potential platform for the design of a fluorescent chemodosimeter for extensive anion targets. [ABSTRACT FROM AUTHOR]

Quantitative determination of hemoglobin (Hb) level is an obligatory part of diagnostic proceedings and an undisputed health index for a number of chronic diseases. In this study, we have tried to introduce a new 9-N-substituted berberine analogue (BR-N) as a triumphant fluorescent sensor for aptly selective and extremely sensitive nanomolar detection of Hb. The probe was found to endure a rampant quenching in its highly intensified inherent fluorescence emission with successive addition of Hb. Though, the other available proteins and biomolecules were proved to be failure in causing any significant change in fluorescence of BR-N under equivalent experimental condition. Again, the sensitivity of the probe was such that it provided an astonishing detection limit of 0.41 nM having linearity range 1–70 nM. Noteworthy, the presence of Hb caused significant alternation in the nature of the intrinsic fluorescence curve of the probe which was also a differentiating aspect during Hb identification. Experiments revealed that ground state probe-protein complex formation was behind the reduction of fluorescence intensity through static quenching mechanism. The interaction study unearthed the binding constant value to be 2.8 × 105 M−1. Moreover, the probe was also successful when applied in real samples for quantitative Hb determination which spoke for its reliable practical utility in the field of clinical diagnosis from today onwards. Unlabelled Image • Single-step synthesis of a novel 9-N-substituted berberine derivative. • Selective static quenching of the inherently elevated fluorescence intensity by Hb. • Sensitive Hb recognition with 0.41 nM detection limit and 1–70 nM linearity range. • Fast, facile, fluorometric Hb detection with reliable real sample application. [ABSTRACT FROM AUTHOR]