Ultrasensitive Virion Immunoassay Platform with Dual-Modality Based on a Multifunctional Aggregation-Induced Emission Luminogen

Sensitive
and accurate detection of highly contagious virus is
urgently demanded for disease diagnosis and treatment. Herein, based
on a multifunctional aggregation-induced emission luminogen (AIEgen),
a dual-modality readout immunoassay platform for ultrasensitive detection
of viruses has been successfully demonstrated. The platform is relied
on virions immuno-bridged enzymatic hydrolysis of AIEgen, accompanying
with the in situ formation of highly emissive AIE
aggregates and shelling of silver on gold nanoparticles. As a result,
robust turn-on fluorescence and naked-eye discernible plasmonic colorimetry
composed dual-signal is achieved. By further taking advantage of effective
immunomagnetic enrichment, EV71 virions, as an example, can be specifically
detected with a limit of detection down to 1.4 copies/μL under
fluorescence modality. Additionally, semiquantitative discerning of
EV71 virions is realized in a broad range from 1.3 × 103 to 2.5 × 106 copies/μL with the naked eye.
Most importantly, EV71 virions in 24 real clinical samples are successfully
diagnosed with 100% accuracy. Comparing to the gold standard polymerase
chain reaction (PCR) assay, our immunoassay platform do not need complicated
sample pretreatment and expensive instruments. This dual-modality
strategy builds a good capability for both colorimetry based convenient
preliminary screening and fluorescence based accurate diagnosis of
suspect infections in virus-stricken areas.