An overview on the development of different optical sensing platforms for adenosine triphosphate (ATP) recognition

Adenosine triphosphate (ATP), one of the biological anions, plays a crucial role in several biological processes including energy transduction, cellular respiration, enzyme catalysis and signaling. ATP is a bioactive phosphate molecule, recognized as an important extracellular signaling agent. Apart from serving as a universal energy currency for various cellular events, ATP is also considered a factor responsible for numerous physiological activities. It regulates cellular metabolism by breaking phosphoanhydride bonds. Several diseases have been reported widely based on the levels and behavior of ATP. The variation of ATP concentration usually causes a foreseeable impact on mitochondrial physiological function. Mitochondrial dysfunction is responsible for the occurrence of many severe diseases such as angiocardiopathy, malignant tumors and Parkinson's disease. Therefore, there is high demand for developing a sensitive, fast-responsive, nontoxic and versatile detection platform for the detection of ATP. To this end, considerable efforts have been employed by several research groups throughout the world to develop specific and sensitive detection platforms to recognize ATP. Although a repertoire of optical chemosensors (both colorimetric and fluorescent) for ATP has been developed, many of them are not arrayed appropriately. Therefore, in this present review, we focused on the design and sensing strategy of some chemosensors including metal-free, metal-based, sequential sensors, aptamer-based sensors, nanoparticle-based sensors etc. for ATP recognition via diverse binding mechanisms.

Imidazolium Based Probes for Recognition of Biologically and Medically Relevant Anions

The imidazolium derivatives due to their positive charge possess one of the most polarized and positively charged proton at C2-H to form strong ionic hydrogen bond (also termed as double ionic hydrogen bond) with anions and also provide opportunities for anion - π interactions with electron-deficient imidazolium ring. In the present review article, imidazolium based molecular probes for their ability to recognize inorganic anions like halides, cyanide, perchlorate, carboxylic acids, phosphate, sulfate etc. and their derived molecules viz. nucleotides, DNA, RNA, surfactants, proteins, etc have been discussed. The review covers the literature published after year 2009 and has > 130 references. The previous literature has already been discussed by Yoon et al. in two review articles published in Chem. Soc. Rev. 2006 and 2010.

1,8-naphthalimide modified [12]aneN₃ compounds as selective and sensitive probes for Cu²⁺ ions and ATP in aqueous solution and living cells

A new fluorescent probe 1 featuring one 1,8-naphthalimide and two [12]aneN3 units was synthesized. In the presence of Cu(2+) ions, the fluorescence emission of 1 was quenched by a factor of 127-fold and no interference by other metal ions was observed under physiological conditions. By means of titration and a Job's plot it was established that 1 forms a complex with Cu(2+) ions in a 1:2 ratio. The fluorescence of the 1-Cu(2+) complex was recovered by the addition of Adenosine-5'-triphosphate (ATP) in aqueous solution. Due to its low cytotoxicity, good water solubility, and high sensitivity, probe 1 was successfully applied in the sequential recognition of Cu(2+) and ATP in aqueous solution and HeLa cells. The highly selective and sensitive ability of 1-Cu(2+) complex to detect ATP even enables its bio-analytical applications in real-time imaging in living cells.

Pyridinum-based flexible tripodal cleft: a case of fluorescence sensing of ATP and dihydrogenphosphate under different conditions and cell imaging

Pyridinium-based chemosensor 1 built on tris(aminomethyl)amine (tren) has been designed, synthesized and established as a chemosensor for ATP over ADP, AMP and a series of other anions in aqueous CH₃CN at pH 6.5.