Controlled copper in situ growth-amplified lateral flow sensors for sensitive, reliable, and field-deployable infectious disease diagnostics
2021
Zhou, Yaofeng | Chen, Yuan | Liu, Yang | Fang, Hao | Huang, Xiaolin | Leng, Yuankui | Liu, Zhengqiong | Hou, Li | Zhang, Wei | Lai, Weihua | Xiong, Yonghua
A polyethyleneimine (PEI)-assisted copper in-situ growth (CISG) strategy was proposed as a controlled signal amplification strategy to enhance the sensitivity of gold nanoparticle-based lateral flow sensors (AuNP-LFS). The controlled signal amplification is achieved by introducing PEI as a structure-directing agent to regulate the thermodynamics of anisotropic Cu nanoshell growth on the AuNP surface, thus controlling shape and size of the resultant AuNP@Cu core–shell nanostructures and confining free reduction and self-nucleation of Cu²⁺ for improved reproducibility and decreased false positives. The PEI-CISG-enhanced AuNP-LFS showed ultrahigh sensitivities with the detection limits of 50 fg mL⁻¹ for HIV-1 capsid p24 antigen and 6 CFU mL⁻¹ for Escherichia coli O157:H7. We further demonstrated its clinical diagnostic efficacy by configuring PEI-CISG into a commercial AuNP-LFS detection kit for SARS-CoV-2 antibody detection. Altogether, this work provides a reliable signal amplification platform to dramatically enhance the sensitivity of AuNP-LFS for rapid and accurate diagnostics of various infectious diseases.
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