Ultrasensitive plasmonic photothermal immunomagnetic bioassay using real-time and end-point dual-readout

One of the most straightforward and sensitive methods for combining the specificity of immunological recognition with the amplification capability of polymerase chain reaction (PCR) is the fluorescence-based immuno-PCR. But up until now, the majority of PCR-based immunoassays have utilized the pricey and lengthy Peltier-based heating technique. Herein, we introduce a plasmonic photothermal quantitative immuno-PCR (PPT-qiPCR) assay with real-time and end-point dual readout for biomarker detection using multifunctional plasmonic immunomagnetic nanoparticles (PIMNs). PPT-qiPCR is simple, time-saving and inexpensive compared with conventional iPCR platforms using PCR machine. We showed that an immunomagnetic technique utilizing PIMNs can shorten the time needed for collection, washing, and concentrating target proteins in the enzyme-linked immunosorbent assay (ELISA) procedure. Real-time readout also permits quick preliminary discrimination of target proteins with apparent sensitivity in commercial ELISA investigations. Additionally, in-situ end-point fluorescence or colorimetric detection using only the human eye considerably improve the assay sensitivity. Our PPT-qiPCR can significantly advance next-generation point-of-care molecular diagnostic technology and is anticipated to be immediately useful for the sensitive and quick identification of several disease biomarkers.