Affinity-Switchable Interaction of Biotin and Streptavidin for the Signal-ON Detection of Small Molecules.

Lateral flow assay (LFA) based on gold nanoparticles (AuNPs) is a widely used analytical device for the rapid analysis of environmental hazards and biomarkers. Typically, a sandwich-type format is used for macromolecule detection, in which the appearance of a red test line indicates a positive result (Signal-ON). In contrast, small molecule detection usually relies on a competitive assay, where the absence of a test line indicates positive testing (Signal-OFF).

Small Plasma Membrane-Targeted Fluorescent Dye for Long-Time Imaging and Protein Degradation Analyses.

Plasma membrane (PM)-targeted fluorescent dyes have become an important tool to visualize morphological and dynamic changes in the cell membrane. However, most of these PM dyes are either too large and thus might potentially perturb the membrane and affect its functions or exhibit a short retention time on the cell membrane. The rapid internalization problem is particularly severe for PM dyes based on cationic and neutral hydrophobic fluorescent dyes, which can be easily transported into the cells by transmembrane potential and passive diffusion mechanisms.

Protein-Labeling Fluorescent Probe for Folate Receptor α.

GPI-anchored folate receptor α (FRα) is an attractive anticancer drug target and diagnosis marker in fundamental biology and medical research due to its significant expression on many cancer cells. Currently, analyses of FRα expression levels are usually achieved using immunological methods. Due to the continual FRα synthesis and degradation, immunological methods are not suitable for studying real-time dynamic activities of FRα in living cells.

Protein-Labeling Fluorescent Probe Reveals Ectodomain Shedding of Transmembrane Carbonic Anhydrases.

Ectodomain shedding is a form of limited proteolysis in which a protease cleaves a transmembrane protein, releasing the extracellular domain from the cell surface. Cells use this process to regulate a wide variety of biological events. Typically, immunological detection methods are employed for the analysis of ectodomains secreted into the cultured media.