9-N-substituted novel berberine derivative for selective and sensitive nanomolar level fluorometric detection of human hemoglobin: A synthesis, sensing and interaction study

Quantitative determination of hemoglobin (Fib) 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 x 10(5) 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. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

A new fluorescent sensor, BR-N, was introduced for highly selective and sensitive detection of Hb. The probe showed significant changes in fluorescence emission with the addition of Hb, demonstrating its potential for practical use in clinical diagnosis. The interactions between the probe and Hb were characterized by a static quenching mechanism with a binding constant value of 2.8 x 10(5) M-1.