A Multi‐Signaling Performance for Simultaneous Surveillance and Accretion of Cysteine and Serine in Human Cancer Cell

Differential detection of aspartic acid in MCF-7 breast cancer cells

Aspartic acid is a non-essential amino acid obtained in the neuroendocrine tissues of vertebrates and invertebrates. Aspartic acid, a major excitatory neurotransmitter in the mammalian central nervous system, plays a key role in memory and acts in many other normal and abnormal physiological processes. In this work, we have developed an efficient chemosensor (PCF) based on the pyridine-carbazole moiety for the differential detection of aspartic acid in biological systems. PCF has a strong binding affinity towards aspartic acid, with a detection limit in the nanomolar range. The binding stoichiometry of aspartic aid and PCF was obtained as 1 : 1 from a Jobs plot analysis. Furthermore, the efficacy of PCF has been successfully demonstrated in in vitro experiments in MCF-7 breast cancer cells.

In vivo 'turn on' fluorescence detection of free cysteine in zebrafish kidney and liver

Cysteine is directly associated with a wide range of biological processes. Besides its essential role in protein synthesis, cysteine undergoes a variety of post-translational modifications which modulate several physiological processes. Dysregulated cysteine metabolism is associated with several neurodegenerative disorders. Accordingly, restoring cysteine balance has therapeutic benefits. It is therefore essential to detect the presence of endogenous free cysteine in order to understand different physiological modes of action inside the cell. Here, a carbazole-pyridoxal conjugate system (CPLC) has been developed to detect endogenous free cysteine in the liver and kidney of an adult zebrafish. In consequence, we have also determined the fluorescence intensity statistics of zebrafish kidney and liver images. CPLC interacts in a very fascinating way with two cysteine molecules through chemodosimetric and chemosensing approaches which are conclusively proved by different spectroscopic analyses (UV-vis, fluorescence, NMR) and theoretical calculations (DFT). The detection limit of CPLC towards cysteine is 0.20 μM. Moreover, this preliminary experiment has been done using HuH-7 cell line to check the permeability of CPLC, interaction with cysteine intracellularly, and assessment of the toxicity of CPLC, if any, before performing details in-vivo experiments in zebrafish model.

A handy and accessible tool for identification of Sn(II) in toothpaste

An easily accessible colorimetric probe, a carbazole-naphthaldehyde conjugate (CNP), was successfully prepared for the selective and sensitive recognition of Sn(II) in different commercially-available toothpaste and mouth wash samples. The binding mechanism of CNP for Sn2+ was confirmed by UV-Vis, 1H, and 13C NMR titrations. The proposed sensing mechanism was supported by quantum chemical calculations. Selective detection of Sn(II) in the nanomolar range (85 nM), among other interfering metal ions, makes it exclusive. Moreover, Sn2+ can be detected with a simple paper strip from toothpaste, which makes this method handy and easily accessible. The potential application of this system for monitoring Sn2+ can be used as an expedient tool for environmental and industrial purposes.

Fluorescence ‘off–on–off’ signaling with zinc ensemble: a new array of investigating prevalence of ATP in liver cancer cells

2-Hydroxy naphthaldehyde–picolylamine conjugate (NPAC) ensemble with Zn²⁺ (NPAC–Zn2+) has been synthesized for the selective recognition and estimation of ATP in human liver cancer cells.

A “turn-on” fluorescent sensor for cytosine in aqueous media based on diamino-bridged biphenyl acrylonitrile

A “turn-on” fluorescent sensor for cytosine in aqueous media was prepared.