Fig 1.
Schematic representation of the LSPR-amplified immunofluorescence biosensor.
Anti-NS1 antibody-conjugated AuNPs and QDs are captured ZIKV. LSPR is induced by the close distance of two nanoparticles and enhances the fluorescence intensity.
Fig 2.
UV/vis absorption spectra (A) and TEM images (B–E) of the thiol-capped AuNPs. (B), (C), (D), and (E) denote GSH-, TGA-, MPA-, and L-cyst-conjugated AuNPs, respectively.
Table 1.
Hydrodynamic sizes and Zeta potential values of the thiol-capped AuNPs and the Ab-AuNPs.
Fig 3.
FT-IR spectra of thio-functionalized AuNPs and their binding assay.
AuNPs were conjugated by GSH (A), TGA (B), MPA (C), and L-cys (D). (E) ELISA showing the strong binding affinity of the Ab to the QDs and AuNPs. The 2% of BSA was used as a negative control.
Fig 4.
Fluorescence intensity in ZIKV detection using Ab-MPA-AuNPs and Ab-QDs and calibration curve.
Fluorescence enhancement spectra (A) of the Ab-QDs and calibration curve (B) of the recombinant NS1 antigen using the LSPR signal amplifier of Ab-MPA-AuNPs.
Fig 5.
Calibration curves of ZIKV detection using 4 kinds of thiol-functionalized AuNPs.
The LSPR signal amplifiers of L-cyst-AuNPs (red closed circles) and Ab-MPA-AuNPs (black closed circles) showed higher correlation coefficients than those of Ab-GSH-AuNPs (black open circles) and Ab-TGA-AuNPs (yellow open circles).
Fig 6.
Fluorescence enhancement calibration curve.
(A) Ab-MPA-AuNPs and (B) Ab-L-cyst-AuNPs were used to detect ZIKV and insets show TEM images of QD-Ab-ZIKV-Ab-MPA-AuNPs and QD-Ab-ZIKV-Ab-L-cyst-AuNPs, respectively. Detection media are in human serum (closed red circles) and in DI water (open circles).
Table 2.
Comparison of detection methods in terms of ZIKV detection.
Fig 7.
Specificity of our proposed detection method.
Fluorescence intensity of ZIKV was compared with those of NoV-LPs, influenza virus A (H7N7) BSA, and BSA as negative control. The concentration of the sample used was 100 ng/mL for NoV-LPs and influenza virus A (H7N7) and 1×105 RNA copies/mL for the ZIKV.