A highly selective fluorescence sensor for cysteine/homocysteine and its application in bioimaging

Abstract

A new near-infrared (NIR) sensitive Cys/Hcy probe based on squaraine was rationally designed and synthesized.

A Squaraine Derivative for Cost‐Effective, Quick, and Highly Sensitive Determination of Mercury and Thiols and pH Sensing

“…Further absorbance measurements with selected thiols, in concentrations ranging from 5.0×10 −7 to 5.0×10 −4 m , were also performed in order to calculate the linear range and the limit of detection (LOD) for each thiol. The reduction of the absorbance of IndSq in the presence of, for example, cysteine was linear in the range of 1.0×10 −6 to 2.1×10 −5 m , while the detection limit of IndSq was determined to be 8.74×10 −7 m (3.3×SD blank ) [8.70×10 −7 m (3.3×SD y/x )], similar to the LOD (calculation based on SD blank ) of other squaraines reported in the most recent literature . Broader linear ranges can also be acquired to determine higher concentrations of thiols, however, at the expense of sensitivity, if log(Abs) or (Abs blank −Abs sample )/Abs sample is plotted against the thiol concentration .…”

“…The reduction of the absorbance of IndSq in the presence of, for example, cysteine was linear in the range of 1.0 10 À6 to 2.1 10 À5 m,w hile the detection limit of IndSq was determined to be 8.74 10 À7 m (3.3 SD blank )[ 8.70 10 À7 m (3.3 SD y/x )],s imilar to the LOD( calculation based on SD blank )o fo ther squaraines reported in the most recent literature. [27] Broader linear ranges can also be acquired to determine higherc oncentrationso ft hiols, however, at the expense of sensitivity,i fl og(Abs) or (Abs blank ÀAbs sample )/Abs sample is plotted against the thiol concentration. [8] Additionally,l ike most of the squaraine dyes, IndSq suffers from low solubility in completely aqueous media due to the formation of aggre-Scheme1.Structure of the conventional squaraines used as thiol and ion probes(left), as well as IndSq (right).…”

An off-on fluorescent probe for specifically detecting cysteine and its application in bioimaging

“…In recent times, fluorescent molecular probes have emerged as an attractive tool for selective detection of various chemical and biological components [6][7][8][9][10], including thiols [11][12][13][14][15][16][17]. Compared to traditional techniques, chemical probes based on absorption or fluorescence changes are more feasible for detecting analyses owing to their many appealing advantages such as low detection limit, high selectivity, its real-time monitoring and its potential for vivo imaging of living cells.…”

Highly sensitive fluorogenic sensing of L-Cysteine in live cells using gelatin-stabilized gold nanoparticles decorated graphene nanosheets

“…The resultant plot shows a linearity over the initial concentrations of L-Cys (Fig. This result suggests that our proposed sensor is better than that of the previous reports [9,18,19,25,28,[51][52][53][54][55][56][57][58][59][60][61][62][63]. The LOD of L-Cys was calculated to be 0.51 nM, revealing that this nanohybrid based sensor system showed a higher sensitivity towards the detection of L-Cys.…”