Polydentate Aromatic Nanoparticles Complexed with Cu²⁺ for the Detection of Cysteamine Using a Smartphone as a Portable Diagnostic Tool

Abstract

Despite the significant therapeutic use of cysteamine as drug in cystinosis, it also has some serious health issues such as idiopathic intracranial hypertension (IIH), Ehlers–Danlos syndrome, and eye related problems including blurred or loss of vision and pain due to eye movement, etc. Thus, it is important to measure accurate cysteamine levels in the body for clinical studies. However, most of the conventional methods used to detect cysteamine are time-consuming and expensive in nature. Therefore, in this regard, we have developed a chromogenic sensor which sequentially determines the Cu2+ metal ion and, consequently, exhibits potential ratiometric and selective colorimetric quantification of cysteamine in an aqueous/biological system. The morphology of the sensor was characterized by TEM, and it revealed some interesting features in that receptor 1 nanoparticles undergo self-assembly with the addition of Cu2+ metal ions which results in the filament formation (comet type) in aqueous medium and on subsequent addition of cysteamine to resultant complex 1·Cu2+; these comet type nanoparticle filaments undergo further aggregation process and develop into three-dimensional tree-like structure. Further, on the basis of obtained colorimetric results, we developed silica-based solid state sensor strips impregnated with complex 1·Cu2+, which displays colorimetric changes in accordance with present concentrations of cysteamine in blood serum and urine samples, wherein the intensity of yellow color decreased gradually after the addition of cysteamine, as revealed by HSV parameter through lab-on-mobile based diagnostics. The low detection limit (with naked eye) exhibited by developed solid state sensors leads to affordable and economic platforms for easy-to-use, reliable, and rapid colorimetric sensing of cysteamine in aqueous as well as biological test systems.

Organoselenium ligands for heterogeneous and nanocatalytic systems: development and applications

“…O-Arylation of phenol is an example of C-O coupling in which phenol couples with aryl halides to give diaryl ethers as the product and has various applications in pharmaceuticals, polymers 127 and agrochemicals. 127 For this reaction, a variety of copper based nanocatalytic 128 and heterogeneous catalytic systems are reported. 20,23 In order to avoid the harsh reaction conditions required during catalysis by Cu based systems, the researchers have focused on alternative metals (including palladium) too.…”

“…Copper containing catalytic systems (such as GO-Cu 1.8 S) require tetrabutylammonium bromide as an additive 128 while GO-Pd 17 Se 15 and H5 do not. Moreover, H5 can catalyse the reaction in a green solvent "water" while most other catalytic systems require DMSO as a solvent.…”

A Copper (II) Ensemble-Based Fluorescence Chemosensor and Its Application in the ‘Naked–Eye’ Detection of Biothiols in Human Urine

“…GSH, as the most abundant cellular biothiol, might cause oxidative stress and some other serious illness including cancers and AIDS [11][12][13]. In view of their importance, developing safe, highly specific and sensitive detection methods for biothiols in living systems is strongly desired in biochemistry and biomedicine research fields [14].…”

“…The practical application of L-Cu 2+ was then demonstrated by the detection of biothiols in human urine sample. developing safe, highly specific and sensitive detection methods for biothiols in living systems is strongly desired in biochemistry and biomedicine research fields [14].Among various conventional methods such as electrochemical approaches [15,16], high-performance liquid chromatography (HPLC) [17,18], gas chromatography [19,20] and mass spectrometry (MS) [21], fluorescence analysis using a responsive molecular probe or chemosensor has been recognized as one of the most promising approaches due to its excellent sensitivity, selectivity, and capability of detecting analytes in live biological specimens [22][23][24][25][26]. To date, a large number of fluorescence chemosensors aiming to distinguish biothiols from other amino acids and bioactive species have been developed based on several sensing mechanisms: (1) Michael addition [27-29]; (2) cyclization with aldehyde [30,31]; (3) the cleavage of sulfonamide, sulfonate esters, selenium-nitrogen bonds and disulfide bonds [32][33][34][35][36][37][38]; (4) intramolecular elimination [39,40].…”

“…The practical application of L-Cu 2+ was then demonstrated by the detection of biothiols in human urine sample. developing safe, highly specific and sensitive detection methods for biothiols in living systems is strongly desired in biochemistry and biomedicine research fields [14].…”