Silver-Platinum Hollow Nanoparticles as Labels for Colorimetric Lateral Flow Assay

Article Silver-Platinum Hollow Nanoparticles as Labels for Colorimetric Lateral Flow Assay Jinfeng Zhou 1, Shikuan Shao 1, Zhiyuan Wei 1 and Xiaohu Xia 1,2,* 1 Department of Chemistry, University of Central Florida, Orlando, FL 32816, USA 2 NanoScience Technology Center, University of Central Florida, Orlando, FL 32816, USA * Correspondence: xiaohu.xia@ucf.edu Received: 23 September 2024; Revised: 7 November 2024; Accepted: 12 November 2024; Published: 18 November 2024 Abstract: Colorimetric lateral flow assay (CLFA) has been a widely recognized point-of-care testing technology over the past few decades. Driven by the increasing demand in various biomedical applications, it is urgently needed to develop CLFAs with high sensitivities and low costs. In this work, we report a type of CLFA that relies on unique colorimetric labels—silver-platinum hollow nanoparticles (Ag-Pt HNPs). The Ag-Pt HNPs possess intrinsic enzyme-like catalytic activities, providing the Ag-Pt HNP-based CLFA with strong color signal and thus a high sensitivity. Meanwhile, the Ag-Pt HNPs have hollow interiors and are mainly composed of less expensive silver, making the Ag-Pt HNP-based CLFA cost-effective. Using prostate-specific antigen (PSA) as a model disease biomarker, the Ag-Pt HNP-based CLFA achieved a high sensitivity with a detection limit at the low picogram-per-milliliter level. Potential application of the CLFA in clinical diagnosis was demonstrated by detecting PSA from human serum samples.