Fast and sensitive detection of protein concentration in mild environments

Bioconjugation of Meldrum's acid activated furan: A detergent compatible assay for protein quantitation

A simple yet efficient assay for the quantitation of proteins ranging from plasma proteins to purified proteins from whole cell lysate, based on the bioconjugation reaction between protein and Meldrum's acid Activated Furan (MAF) is described. This easy to use, sensitive method is based on the conjugation of amine functionalities present on the protein with MAF to form the corresponding Donor Acceptor Stenhouse Adducts (DASAs) with characteristic absorption in the visible region. The reaction is rapid as well as reproducible and shows a proportionate increase in color change over a broad range of protein concentration. The assay was found to be sensitive up to 0.125 mg/mL concentration of the protein and was compatible with most of the commonly employed detergents and isolation protocols which makes it ideal for the estimation of protein samples containing detergents. Another striking feature of this protocol is its tolerance towards other major interference contributors such as chelating agents, reducing agents, carbohydrates and protease inhibitors.

In situ imaging of intracellular human telomerase RNA with molecular beacon-functionalized gold nanoparticles

Since the expression level of human telomerase RNA (hTR) in tumor cells is much higher than that in normal cells, the determination of hTR is of prime importance in biological research of tumors. In this work, we report molecular beacon-functionalized gold nanoparticles for hTR imaging in live cells. The molecular beacon has a loop-and-stem structure with hTR recognition sequences and a red fluorophore Cy5. In the presence of hTR, the hTR sequence could be hybridized with the loop of molecular beacon to form a duplex DNA chain and thus the fluorescence state switched from "off" to "on". After co-incubation with cells, the probe could readily permeate into cells, leading to the in situ imaging of intracellular hTR. The proposed approach could be used to differentiate tumor cells from normal ones and assess hTR expression levels in different tumor cells. Furthermore, the proposed approach allowed us to dynamically monitor the expression level of hTR in live cells and holds great potential for application in tumor diagnosis and hTR-related drug delivery.

A graphene/Si Schottky diode for the highly sensitive detection of protein

Herein, a graphene/Si-based device was introduced for bovine serum albumin (BSA) sensing.