Abstract
With growing concerns about health issues worldwide, elegant sensors with high sensitivity and specificity for virus/antigens (Ag) detection are urgent to be developed. Homogeneous immunoassays (HIA) are an important technique with the advantages of small sample volumes requirement and pretreatment-free process. HIA are becoming more favorable for the medical diagnosis and disease surveillance than heterogeneous immunoassays. An important subset of HIA relies on the effect of fluorescence resonance energy transfer (FRET) via a donor-acceptor (D–A) platform, e.g., quantum dots (QDs) donor based FRET system. Being an excellent plasmonic material, silver triangular nanoplates (STNPs) have unique advantages in displaying surface plasmon resonance in the visible to near infrared spectral region, which make them a better acceptor for pairing with QDs in a FRET-based sensing system. However, the reported STNPs generally exhibited broad size distributions, which would greatly restrict their application as HIA acceptor for high detection sensitivity and specificity purpose. In this work, uniform STNPs and red-emitting QDs are firstly applied to construct FRET nanoplatform in the advanced HIA and further be exploited for analyzing virus Ag. The uniform STNPs/QDs nanoplatform based medical sensor provides a straightforward and highly sensitive method for Ag analysis in homogeneous form.
Highlights
Immunoassays induced by the variation of fluorescent intensity[1,2,3,4,5,6,7], and have already been a top choice as a donor candidate for fluorescence resonance energy transfer (FRET) via D–A system
The silver triangular nanoplates (STNPs) prepared according to the previous method are often difficult to obtain high uniformity in size and morphology, which will potentially restrict their application as Homogeneous immunoassays (HIA) acceptor to meet the demand of high detection sensitivity and repeatability, let alone in real world applications in the future
We further improved our sensor design based on the reported prototype[1,20] and demonstrated the quantum dots (QDs)-STNPs based FRET sensor for detection of Hepatitis B surface antigen (HBsAg)
Summary
Immunoassays induced by the variation of fluorescent intensity[1,2,3,4,5,6,7], and have already been a top choice as a donor candidate for FRET via D–A system. Their absorption and scattering bands could be tuned into red-light wavelength by adjusting the size of the STNPs15–18. This red plasmon resonance absorption band can match well with the emission window of CdTe QDs, which have been generally used in aqueous system. QDs’ emission and STNPs’ plasmon absorption were size-adjusted to ensure an high FRET efficiency by optimizing the spectral overlap range between the emission band of QDs and absorption band of the STNPs16,17. As far as we know, this work provides the first report on employing QDs as donors and STNPs as acceptors to construct FRET platform for HIA of virus antigen
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