A Plasmonic Nanosensor for Immunoassay via Enzyme-Triggered Click Chemistry

Abstract

Current techniques for plasmonic immunoassay often require the introduction and additional conjugation of enzyme, and thus cannot accommodate conventional immunoassay platforms. Herein, we develop a plasmonic nanosensor that well accommodates conventional immunoassays and dramatically improves their sensitivity and stability. This plasmonic nanosensor directly employs alkaline phosphatase-triggered click chemistry between azide/alkyne functionalized gold nanoparticles as the readout. This straightforward approach broadens the applicability of nanoparticle-based immunoassays and has great potential for applications in resource-constrained settings.

Iodine-Mediated Etching of Gold Nanorods for Plasmonic ELISA Based on Colorimetric Detection of Alkaline Phosphatase

“…According to the 3σ rule, the detection limit for human IgG is calculated to be 100 pg/mL, which is at least 1 order of magnitude lower than that of other plasmonic methods 39−41 and even comparable with the results obtained from many sensitive electrochemical methods. 42−45 Additionally, compared to other nanoparticle-based ELISA methods, this method also exhibits many advantages: (1) it is easier to adapt to the conventional ELISA platforms directly, since ALP-labeled antibodies are commercially available; 21,45,53,54 (2) there is no false positive signal coming from nanoparticles autoaggregation, 37,54 as the signal does not come from nanoparticle aggregation; (3) it is label-free for AuNRs, making it much easier to operate; 37,54 and (4) AuNRs are much more stable to light, temperature, and biological thiol than silver nanoprims. 21,22 Determination of Human IgG in Fetal Bovine Serum.…”

A Dispersion-Dominated Chromogenic Strategy for Colorimetric Sensing of Glutathione at the Nanomolar Level Using Gold Nanoparticles

“…[ 7 ] Researchers have generally resorted to target-induced aggregation of AuNPs to detect specifi c analytes. [ 8 ] One of the hurdles the aggregation of AuNPs, although free arginine may exist in the solution which contributes little to the aggregation of AuNPs.…”

Materials for Microfluidic Immunoassays: A Review

“…The released ascorbic acid can reduce Cu 2+ to generate Cu(I) which triggers AuNPs aggregation by Cu(I)-catalyzed azide/alkyne cycloaddition (CuAAC) (Figure 7a). [54] The LOD by naked-eye readout of Rabbit antihuman IgG is 80 ng/mL using CuAAC-mediated AuNP-based immunoassay, which is lower than the concentration of 1000 ng/mL in conventional ELISA for the visible readout. Serum samples from patients who suffered from Mycoplasma pneumonia (MP) infection was applied for this AuNPbased immunoassay.…”