Beyond “turn-on” readout: from zero background to signal amplification by combination of magnetic separation and plasmon enhanced fluorescence

Abstract

By magnetic separation and subsequent plasmon enhanced fluorescence, an assay platform with a signal output from completely "zero" background to fluorescence amplification is achieved, using quantum dots as reporters. So, it well breaks through the conventional "turn-on" strategy in both lower and upper limits. The sensitivity for hyaluronidase sensing is enhanced 10(4)-10(6) times as compared with previous fluorescence methods.

Recent Advances in Design of Fluorescence-Based Assays for High-Throughput Screening

“…To improve the intensity, photostability, and multiplex capacity of fluorescent labels, many fluorescent nanomaterials have been developed, such as quantum dots, upconversion nanoparticles, and semiconducting polymer dots. , Their size- or shape-controllable optical characteristics diversify the selection of diverse probes for enhanced assay throughput. In addition, nanomaterials can simplify fluorescence-based assays by acting as the solid support for the target recognition unit. − Nanomaterials are also adopted for functions other than signaling, including enriching target molecules and quenching interferences. − Therefore, fluorescent nanomaterials have been gradually replacing conventional fluorophores as the signaling units in fluorescence-based assays.…”

Enhanced detection of ascorbic acid with cascaded fluorescence recovery of a dual-nanoquencher system

“…Therefore, reducing or even eliminating the background signal can improve the detection sensitivity greatly. 2 The usage of nanomaterials as ‘‘nanoquenchers’’ can reduce the background fluorescence of a fluorophore efficiently owing to their higher quenching efficiency. Gold nanoparticles (AuNPs), as a typical noble metal nanomaterial with a very large molar extinction coefficient, can quench fluorescein 100 times more efficiently than organic quenchers.…”

A microchip electrophoresis-based fluorescence signal amplification strategy for highly sensitive detection of biomolecules

“…Recently, some other signal amplification techniques have also been shown as a good alternative to traditional analytical methods for improving the sensitivity of biomolecules detection, such as signal-amplifiable supramolecular hydrogel, 17 hyper-branched hybridization chain reaction, 18 spherical nucleic acids gold nanoparticles triggered mimic-hybridization chain reaction enzyme-free dual signal amplification, 19 fluorescence polarization signal amplification based on structure-switching-triggered nanoparticles enhancement, 20 signal amplification based on combination of magnetic separation and plasmon enhanced fluorescence, 21 DNase I-assisted target recycling signal amplification, 22 and electrophoresis separation assisted chemiluminescence (CL) signal amplification. 23 …”