Albumin is the most abundant serum protein and shows variation in its synthesis rate in different physiological and pathophysiological conditions. Thus, there might be an association expected between serum albumin concentration and body health. A library of NIR probes engineered with the optimum hydrophobicity has been developed and characterized using spectroscopy techniques and was employed to understand the variation of hepatic albumin synthesis rates on physiological and pathophysiological states. Given the importance of hydrophobicity in rendering an effective interaction of small molecules with biomolecules, strategic structure interaction relationship studies led us toward the development of a potent emissive molecular probe through chemical library development. By exploration of these newly developed molecular probes, our study elegantly showed how a pathophysiological condition like the hyperinsulinemic state significantly downregulates albumin biosynthesis in HepG2 cells using fluorescence microscopy as a tool. An excellent correlation between the albumin transcript level and fluorescence intensity inside the cells has been observed. The key role of hydrophobicity resulting in an effective interaction of the probes with albumin, thus leading to strong optical signals, has been experimentally demonstrated in this report. Also, a siRNA interference technique has been utilized to establish the excellent selectivity of the developed probes with excitation as well as emission in the NIR region. We therefore have established through our experimental findings that suitable cell permeable emissive molecular markers with a high degree of albumin specificity can be used as a good optical tool for studying the effect of hyperinsulinemia on albumin biosynthesis modulation.

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With the promising advantages of the near-infrared region (NIR) emissive markers for serum albumin becoming very prominent recently, we devised CyG-NHS as the cyanine derived longest NIR-I emissive optical marker possessing albumin selective recognition ability in diverse biological milieu.

Despite its murderous act, carbon monoxide (CO) is found to be a very crucial small gaseous messenger molecule in dictating prime biological and physiological processes. Determination of endogenous or exhaled CO levels can throw significant light on smoking status and can be used as a breath biomarker of inflammatory diseases. Therefore, fluorescence imaging of CO in biofluids will empower one with the minute details of various disease states that involve CO. Unfortunately, such efficient fluorescent probes are less in number and also associated with tedious protocols. This enticed our attention and inspired us to look upon developing perceptive imaging agents for CO in a living system. In this report, a resorufin-based "turn-on" orange emissive molecular probe has been successfully utilized to detect CO in an aqueous system. The mono protection of a resorufin unit with an allyl chloroformate furnished a weakly fluorescent small molecular probe P1. Further, the P1+Pd 2+ ensemble has been successfully developed in situ using PdCl 2 (as Pd 2+ ) and utilized as a light-up signaling mechanism tool for the sensing of CO at the nanomolar level (62 nM) through deprotection mechanism. The probe selectively detects CO without any interference from other anions, gasotransmitters and fatty acids. The present integrated probe P1+Pd 2+ system has been found to be highly sensitive to detect CO in cellular systems as well.

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