Dual‐Mode Optical Sensing of Histamine at Nanomolar Concentrations in Complex Biological Fluids and Living Cells

Bhattacharya

2017

Anal. Chem.

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A pyrene based amphiphilic receptor has been utilized in the nanomolar detection of uric acid at physiological pH in water. The compound shows a unique concentration-dependent modulation in optical response toward uric acid. In intramolecular/static excimer form (low concentration range), it displays a ratiometric response, while a "turn-off" sensing is observed specifically in the presence of intermolecular/dynamic excimer (high concentration range). The present protocol is then employed for the estimation of uric acid in blood serum samples of healthy individuals. Bland-Altman analysis in comparison to clinically approved uricase assay indicated the high accuracy of the present method. Additionally, the extent of insect infestation in stored grain samples was determined by measuring the uric acid content of their aqueous extracts. Low-cost color strips were developed for on-site detection of uric acid without involving any sophisticated instrument or trained personnel.

“…Subsequently, compound 1 was employed for imaging intracellular UA in HeLa cells . For this, the first cytotoxicity of the probe was assayed using MTT as the indicator dye (Figure S20b).…”

Section: Resultsmentioning

confidence: 99%

Nanomolar Level Detection of Uric Acid in Blood Serum and Pest-Infested Grain Samples by an Amphiphilic Probe

Bhattacharya

2017

Anal. Chem.

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“…The changes in emission color were further quantified by ImageJ software (Figure S46). 34 As the sensing using paper strips does not require any expensive visualizing tool, this method will be suitable for on-site detection at open markets or other distant locations (rural areas). The price of each strip will be much less and can even be recycled upon washing with EDTA solution (Figure 11a).…”

Section: Acs Sustainable Chemistry and Engineeringmentioning

confidence: 99%

Microenvironment Sensitive Charge-Transfer Dye for Tandem Sensing of Multiple Analytes at Mesoscopic Interfaces

ACS Sustainable Chem. Eng.

Biswakarma

Gulyani

et al. 2018

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An easy to synthesize amphiphilic dye is developed whose sensing behavior in surfactant assemblies can be modulated through surface-charge, micropolarity, and local pH, etc. Thus, the micelle-bound probe shows remarkable ion-dependent bathochromic shifts in the charge-transfer band, enabling simultaneous ratiometric detection of four different metal ions, such as Cu2+, Ni2+, Hg2+, and Zn2+, at parts per billion (ppb) level in water. This is indeed a striking observation since naked-eye sensing of multiple metal ions at the mesoscopic interface is not known to date. Moreover, the probe even shows distinct color response against copper ion in different oxidation states, which is also unheard of. Further, the in situ formed metal complexes can be employed for naked-eye screening of three different amino acids, such as histidine, cysteine, and aspartic acid, in aqueous medium. Probes of this class, which are capable of multiplexing, offer new ways of efficiently screening multiple analytes in complex, real-life samples (e.g., wastewater management, analysis of pharmaceutical drugs, etc.). Further, low-cost reusable dye-coated paper discs were also developed as an ecofriendly method for on-site sensing of metal ions.

“…Furthermore, the detection limit of compound 1 for HSA in PBS buffer (pH 7.4 at 25 8C) was determined to be 0.27 mg L À1 by using the blank variation method. [37][38][39] Analysis of the thermodynamic parameters (DH and DS) through variable-temperature emission titration studies indicated that compound 1 interacted with HSA through ac ombination of electrostatic and hydrophobic interactions (see the Supporting Information, Table S1). [40] An egative value of DH and ap ositive entropyc hange (DS)a tl = 400 nm suggested that the spectroscopic changes at l = 400 nm wereg overned by electrostatic interactions.A tt he same time, positive changes in both enthalpy and entropyv alues wereo bserved at l = 454 nm, which confirmed the role of hydrophobic interactions in the recognition process.…”

Section: Resultsmentioning

confidence: 99%

Motion‐Induced Changes in Emission as an Effective Strategy for the Ratiometric Probing of Human Serum Albumin and Trypsin in Biological Fluids

Chemistry An Asian Journal

Maji

Bhattacharya

2018

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Herein, we report the formation of a highly luminescent, pH-sensitive, thermoreversible nanoaggregate in pure aqueous medium through the self-agglomeration of carbazole-based amphiphiles. The self-assembly process restricted the intramolecular motion of the molecules and induced a change in its emission signal from blue to cyan, owing to an aggregation-induced emission (AIE) effect. A similar type of ratiometric response was also observed in the presence of human serum albumin (HSA). However, in this case, the molecular motion of the flexible fluorescent probe was restricted by its embedded microenvironment, owing to a motion-induced change in emission (MICE) effect, not by aggregation. Moreover, the probe showed quite high selectivity for HSA over other serum albumin proteins. Our carbazole-based fluorescent probes are a unique example of the ratiometric sensing of HSA through the sole involvement of reversible noncovalent interactions. Considering the important of HSA in clinical diagnosis, a wide range of biological fluids, such as human urine, saliva, and plasma, were screened to analyze their HSA content. In addition, this system was also employed for the detection of trypsin at subnanomolar concentrations through the digestion of HSA.