Fluorophore-encapsulated nanobeads for on-site, rapid, and sensitive lateral flow assay

Sung Eun Seo; Eunsu Ryu; Jinyeong Kim; Chan Jae Shin; Oh Seok Kwon

doi:10.1016/j.snb.2023.133364

Fluorophore-encapsulated nanobeads for on-site, rapid, and sensitive lateral flow assay

Sens Actuators B Chem. 2023 Apr 15:381:133364. doi: 10.1016/j.snb.2023.133364. Epub 2023 Jan 13.

Authors

Sung Eun Seo¹, Eunsu Ryu¹, Jinyeong Kim¹, Chan Jae Shin^{1

2

3}, Oh Seok Kwon^{1

2

4

3

5}

Affiliations

¹ Infectious Disease Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, South Korea.
² Department of Biotechnology, University of Science & Technology (UST), Daejeon 34141, South Korea.
³ SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 16419, South Korea.
⁴ College of Biotechnology and Bioengineering, Sungkyunkwan University, Suwon 16419, South Korea.
⁵ Department of Nano Engineering, Sungkyunkwan University, Suwon 16419, South Korea.

Abstract

Since December 2019, the rapid and sensitive detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a priority for public health. Although the lateral flow assay (LFA) sensor has emerged as a rapid and on-site SARS-CoV-2 detection technique, the conventional approach of using gold nanoparticles for the signaling probe had limitations in increasing the sensitivity of the sensor. Herein, our newly suggested methodology to improve the performance of the LFA system could amplify the sensor signal with a facile fabrication method by concentrating fluorescent organic molecules. A large Stokes shift fluorophore (single benzene) was encapsulated into polystyrene nanobeads to enhance the fluorescence intensity of the probe for LFA sensor, which was detected on the test line with a longpass filter under ultraviolet light irradiation. This approach provides comparatively high sensitivity with the limit of detection of 1 ng mL^-1 for the SARS-CoV-2 spike protein and a fast detection process, which takes less than 20 min. Furthermore, our sensor showed higher performance than gold nanoparticle-based commercial rapid diagnostics test kits in clinical tests, proving that this approach is more suitable and reliable for the sensitive and rapid detection of viruses, bacteria, and other hazardous materials.

Keywords: Ab, Antibody; Ag, Antigen; AuNP, Gold nanoparticle; CL, Control line; CT, Threshold cycle; LFA, Lateral flow assay; LOD, Limit of detection; PCR, Polymerase chain reaction; PS, Polystyrene; RDT, Rapid diagnostic test; SARS-CoV-2, Severe acute respiratory syndrome coronavirus 2; SB, Single Benzene; TL, Test line.