Thermal-annealing-regulated plasmonic enhanced fluorescence platform enables accurate detection of antigen/antibody against infectious diseases

Abstract

Plasmonic enhanced fluorescence (PEF) technology is a powerful strategy to improve the sensitivity of immunofluorescence microarrays (IFMA), however, current approaches to constructing PEF platforms are either expensive/time-consuming or reliant on specialized instruments. Here, we develop a completely alternative approach relying on a two-step protocol that includes the self-assembly of gold nanoparticles (GNPs) at the water—oil interface and subsequent annealing-assisted regulation of gold nanogap. Our optimized thermal-annealing GNPs (TA-GNP) platform generates adequate hot spots, and thus produces high-density electromagnetic coupling, eventually enabling 240-fold fluorescence enhancement of probed dyes in the near-infrared region. For clinical detection of human samples, TA-GNP provides super-high sensitivity and low detection limits for both hepatitis B surface antigen and SARS-CoV-2 binding antibody, coupled with a much-improved detection dynamic range up to six orders of magnitude. With fast detection, high sensitivity, and low detection limit, TA-GNP could not only substantially improve the outcomes of IFMA-based precision medicine but also find applications in fields of proteomic research and clinical pathology. Electronic Supplementary Material Supplementary material (UV—Vis absorption and transmission spectra of GNPs, SEM, microscopy and digital images of PEF platforms, and fluorescence images of IFMA on PEF platforms) is available in the online version of this article at 10.1007/s12274-022-5035-6.

Naked-Eye Readable Microarray for Rapid Profiling of Antibodies against Multiple SARS-CoV-2 Variants

“…Moreover, to provide a head-to-head comparison, we performed enhanced immunofluorescence assay (EIFA) where antibody−antigen complexes were visualized by boosting (240-fold enhancement) fluorescence signals from IRDye800CW-labeled secondary antibodies via a plasmonic substrate. 24 Under the same experimental conditions, NRMs produced visible patterns fully matching the fluorescence images of EIFA but without using secondary antibodies and a fluorescence reading device (Figure 3d). The correlation between the results generated by the two methods was verified, and R of 0.881 indicates the NRM-based antibody detection is feasible and reliable (Figure 3e).…”

“…These results were also consistent with the neutralization results produced by the pVNT assays (Figure S9). Moreover, to provide a head-to-head comparison, we performed enhanced immunofluorescence assay (EIFA) where antibody–antigen complexes were visualized by boosting (240-fold enhancement) fluorescence signals from IRDye800CW-labeled secondary antibodies via a plasmonic substrate . Under the same experimental conditions, NRMs produced visible patterns fully matching the fluorescence images of EIFA but without using secondary antibodies and a fluorescence reading device (Figure d).…”

Neural Network Enables High Accuracy for Hepatitis B Surface Antigen Detection with a Plasmonic Platform

“…As mentioned, the use of neural networks significantly improved the accuracy of HBsAg detection. Thus, we made a detailed comparison between the performance of DLPB and conventional immunoassay techniques (i.e., EIFA and LFA). − Using the identical sample set comprising 349 samples, we performed both EIFA and LFA (Figure S19). Overall, with the assistance of MLP for spectral analysis, DLPB achieved a remarkable error rate of 0.34%, lower than the error rate of EIFA, which was 0.93% (Figure S20).…”