Single-Line Flow Assay Platform Based on Orthogonal Emissive Upconversion Nanoparticles

Abstract

Lateral flow assay (LFA) has played pivotal roles in many emergency public safety incidents, such as coronavirus disease diagnostics; however, the present double-line (test and control line) design strategy for LFA strips greatly restricts their applications in high-throughput quantitative analysis because the limited sample diffusion distance on the strips constrains the number of test/control lines. Herein, a novel single-line-based LFA (sLFA) strip, which combines test and control line, is developed by exploiting an orthogonal emissive upconversion nanoparticle (UCNP) as a signal reporter on the test line, where one emission can be used as a reporting signal and the other as a calibrating signal. This UCNP-based test line with an interior reference also can play a validating role as a control line, and hence capturing antibodies are not needed for control lines, greatly saving fabrication costs. As a proof-of-concept, this novel sLFA strip is successfully explored to accurately and rapidly detect aflatoxin B1. Moreover, due to the removal of control lines, such a novel strategy greatly reduces the strip size, facilitating the design of a testing array for multiple detections of different samples. The test line herein is designed in a ring shape, and several test rings are assembled to be a chip for the testing of multiple samples. To our knowledge, this is the first demonstration of single-line-based LFA strips, which will significantly improve the detection capacities and accuracies and reduce the testing costs of LFA strips in real sample applications ranging from food analysis to in vitro diagnostics.

Comparison of paper-based nucleic acid extraction materials for point-of-care testing applications

“…For example, filter paper-based device impregnated with chromogenic substrate reacted with bacterial enzymes to form coloured products for colorimetric detection of S.aureus and E.coli (Asif et al 2020 ; Prabhu et al 2020 ). Upconversion nanoparticles as a signal reporter was immobilized on test line of nitrocellulose membrane for aflatoxin B1 detection (Guo et al 2021 ). Various nanomaterials, such as funtionalized metal nanoparticles and nanozyme, have been used for colorimetric pathogen detection (Nguyen and Kim 2020 ).…”

Recent Advances and Applications in Paper-Based Devices for Point-of-Care Testing

“…For food safety, colormetry method can measure the content of toxin [149][150][151] and drugs [152,153]. A single-linebased LFA (sLFA) strip [150] without the control line was explored for aflatoxin B1 determination.…”

“…For food safety, colormetry method can measure the content of toxin [149][150][151] and drugs [152,153]. A single-linebased LFA (sLFA) strip [150] without the control line was explored for aflatoxin B1 determination. In this assay, an orthogonal emissive upconversion nanoparticle (UCNP) served as a signal substance and calibrator, which had emission at two wavelengths.…”

Recent Progress in Utilizing Upconversion Nanoparticles with Switchable Emission for Programmed Therapy

“…The two events occurred simultaneously will reduce the effective time of action and hence, lowers the overall therapeutic efficiency. This bottleneck and shortage could be overcome based on UCNPs nanoplatform with switchable emission because in that case one emission could be used for imaging, [18,19] and another could be serviced for detection, [73][74][75][76][77][78] delivery, [79][80][81] and PDT. [22,23,[82][83][84][85][86] Kong and co-workers designed one Nd 3+ -free UCNPs with switchable emission, NaErF 4 @NaYF 4 @NaYbF 4 :Tm@NaYF 4 .…”