Glucose and Ethanol Detection with an Affinity-Switchable Lateral Flow Assay

Abstract

The lateral flow assay (LFA) is one of the most successful analytical platforms for rapid on-site detection of target substances. This type of assay has been used in many rapid diagnoses, for example, pregnancy tests and infectious disease prevention. However, applications of LFAs for very small molecules remain a demanding challenge due to the problem of obtaining the corresponding binding partners to form sandwich complexes. In this paper, we report an affinity-switchable (AS) LFA (ASLFA) for the rapid and selective detection of hydrogen peroxide (H2O2), glucose, and ethanol in blood serum and urine samples. Unlike classical LFAs, which rely on the “always on” interaction between the antigen and the antibody, the working principle of ASLFA is based on the gold nanoparticle-conjugated AS biotin probe Au@H 2 O 2 -ASB, which can be activated by H2O2 for binding with the streptavidin (SA) protein. In the presence of glucose and ethanol, glucose oxidase and alcohol oxidase can react with the substrate to generate H2O2 and thereby activate Au@H 2 O 2 -ASB for binding with SA. Therefore, this ASLFA approach can be an alternative for classical glucose and ethanol detection methods in a wide variety of samples, where simple and rapid on-site detection is essential.

Affinity-Switchable Interaction of Biotin and Streptavidin for the Signal-ON Detection of Small Molecules

“…Our previous ASLFA approach was designed and applied to the detection of small reactive molecules (fluoride and hydrogen peroxide) which require strategies involving the covalent bond cleavage of caged biotin. 11,12 In contrast, the target molecules (primary sulfonamide and trimethoprim) reported in this work do not have the chemical reactivity to uncage the caged biotin. Therefore, a completely different Signal-ON ASLFA strategy must be implemented to detect those organic drug molecules.…”

“…Lateral flow assay (LFA) based on gold nanoparticles (AuNPs) is a simple and low-cost analytical device for the rapid analysis of target molecules on site. − As compared with other point-of-care (POC) detection methods, LFA is distinctive as it produces a control line during testing, indicating the correct operation of this POC method. , Over the past decades, a wide variety of LFA strategies have been developed to test many different molecules, including proteins, nucleic acids, small molecules, metal ions, reactive small species, and enzymes. − Currently, several LFA tool kits are available commercially for the rapid testing of pregnancy, infectious diseases, and food safety. − Depending on the type of target molecules, LFA detection can be carried out in either the sandwich or the competitive format. , In the presence of a macromolecule target (e.g., proteins or nucleic acids), LFA tests generate a “Signal-ON” test line when an antibody-analyte-antibody sandwich complex is formed on the membrane. In contrast, small molecules usually lack the multiple binding epitopes required to simultaneously bind with two antibody recognition units.…”

Protein-Labeling Fluorescent Probe for Folate Receptor α

“…In this paper, we report a new and rapid FRα protein-labeling fluorescent probe, FR1 , to study the expression and degradation of FRα in living cells (Figure a). The probe consists of a methotrexate ligand for FRα binding, a membrane-impermeable Cy5 fluorophore, and a reactive group based on a diflurophenyl ester moiety (Figure b). − In the presence of FRα, the difluorophenyl ester group of FR1 can undergo a nucleophilic reaction to form a covalent bond with FRα via an amino acid residue close to the methotrexate binding site. With the labeling of FRα by FR1 , insights on the shedding and protein lifetime of FRα on the plasma membrane can be obtained using various biochemical techniques, such as fluorescence live-cell imaging and electrophoresis.…”

Carbon black as a colorimetric label for an immunochromatographic test strip for severe fever with thrombocytopenia syndrome virus detection

“…14 Metal nanoparticles, such as gold nanoparticles (Au NPs), are the most widely used tracers in the colorimetric-based ICTS. 15,16 However, such ICTSs using Au NPs often have low sensitivity, which limits their application in fields that require more sensitive assays. 10,17 Carbon black, on the other hand, is a more advantageous alternative to Au NPs and colored latex beads.…”