posted on 2020-12-16, 19:33authored byLiang Huang, Jiening Jin, Lijiao Ao, Chenxing Jiang, Yuxing Zhang, Hui-Min Wen, Jing Wang, Haiyan Wang, Jun Hu
Lateral
flow immunoassay (LFIA), as a prominent point-of-care (POC)
test platform, has been extensively adopted for rapid, on-site, and
facile diagnosis of pathogen infections and disease biomarkers. Exploring
novel structured optical labels of LFIA with amplified signal and
complementary detection modes favors the sensitive and flexible POC
diagnosis. Here, bimodal labels with both colorimetric and fluorescent
readout were fabricated via a layered sequential assembly strategy
based on affinity templates and hydrophobic metal-containing nanounits.
High-quality colorimetric and fluorescent nanoparticles were densely
incorporated into the colloidal supports and confined in separated
regions, without interfering with each other. The hierarchical integration
of gold nanoparticles and quantum dots with high loading density and
good optical preservation realized dual readout and amplified signals
from the assemblies of individual single nanoparticles. The “all-in-one”
optical labels allowed both colorimetric and fluorescent detection
of cystatin C (Cys C) after surface conjugation with antibodies. The
LFIA strips revealed noninterfering dual signals for both visual inspection
and quantitative detection of Cys C via the naked eye and portable
devices, respectively. The limits of detection by colorimetric and
fluorescent modes were 0.61 and 0.24 ng mL–1, respectively.
The novel LFIA platform demonstrated sensitive, specific, and reproducible
POC testing of biomarkers with flexible detection modes and was reliable
for clinical diagnosis.