Arginine-Rich Gold Silver–Nanoprobe for Rapid Virus Imaging and Real-Time Tracking in Infected Live-Cells

Virus imaging in infected live-cells is essential for
clinical
diagnostics and virology research. However, conventional nucleic acid
probes suffer from low cellular internalization efficiency and poor
intracellular stability and thus struggle to achieve efficient and
sensitive virus imaging diagnostics. Here, histidine- and arginine-modified
AuAg nanoclusters (CHR) are developed for rapid virus imaging and
high-resolution real-time tracking in infected live-cells. Specifically,
histidine can enhance the fluorescence intensity of AuAg nanoclusters
through an electron-rich group. After conjugating DNA hairpin on CHR
(CHR-h), it can maintain structural stability across pH 4.5–7.4
without false-positive signals. Arginine modification can accelerate
rapid endocytosis through the guanidine-phosphate salt bridge with
cell membrane, inducing CHR-h capture viral RNA within just 1 h via
rapid cellular uptake and high fluorescence signal accumulation in
living cells. Moreover, CHR-h reliably labels SARS-CoV-2’s
genes with high infectivity through multitarget recognition to achieve
real-time tracking of single viral particle. The dynamic separation
of the single viral envelope and RNA is visualized and detailedly
analyzed in the cytoplasm by total internal reflection fluorescence
microscopy, providing insights into SARS-CoV-2’s infection
mechanism in Vero E6 cells. Combining infected live-cell imaging and
real-time tracking capabilities, CHR-h provides an efficient platform
for virology research.