[Show abstract][Hide abstract] ABSTRACT: In this work, we demonstrate a novel estrogenic receptor fragment-based homogeneous fluorescent assay which enables rapid and sensitive detection of 17β-estradiol (E2) and other highly potent estrogens. A modified human estrogenic receptor fragment (N-His×6-hER270-595-C-Strep tag II) has been constructed that contains amino acids 270-595 of wild-type human estrogenic receptor α (hER270-595) and two specific tags (6×His and Strep tag II) fused to the N and C terminus, respectively. The designed receptor protein fragment could be easily produced by prokaryotic expression with high yield and high purity. The obtained protein exhibits high binding affinity to E2 and the two tags greatly facilitate the application of the recombinant protein. Taking advantage of the unique spectroscopic properties of coumestrol (CS), a fluorescent phytoestrogen, a CS/hER270-595-based fluorescent assay has been developed which can sensitively respond to E2 within 1.0min with a linear working range from 0.1 to 20ng/mL and a limit of detection of 0.1ng/mL. The assay was successfully applied for rapid detection of E2 in the culture medium of rat hippocampal neurons. The method also holds great potential for high-throughput monitoring the variation of estrogen levels in complex biological fluids, which is crucial for investigation of the molecular basis of various estrogen-involved processes.
No preview · Article · May 2014 · Biosensors & Bioelectronics
[Show abstract][Hide abstract] ABSTRACT: Quick & easy: A simple and positive-readout fluorescent immunosensor was developed based on a quencher composed of a 3 nm gold nanoparticle (GNP) covalently linked to a Fab fragment, which proved to be stable and specific. The method allows for direct and sensitive detection of target antigens in homogeneous solutions in one step without any separation steps. It has been successfully applied to rapidly quantify the amount of secretory immunoglobulin A (sIgA) in human saliva samples.
No preview · Article · Jul 2012 · Chemistry - An Asian Journal