Highly Sensitive and Ultrastable Lateral Flow Immunoassay Based on Polydopamine-Coated Aggregation-Induced Emission Fluorescent Microspheres with Excellent Fluorescence Performance and Biofriendly Coupling Strategy

Abstract

Conventional fluorescent microspheres (CFMs) have the disadvantages of low photoluminescence intensity (aggregation-caused quenching) and poor antibody conjugation. Herein, we achieved the improved performance of lateral flow immunoassay (LFIA) based on the high-fluorescent property of aggregation-induced emission fluorescent microspheres (AIEFMs) and biofriendly antibody coupling strategy of the polydopamine (PDA) layer. Although the PDA layer quenches the fluorescence intensity of AIEFM by Förster resonance energy transfer (FRET), quenching can be effectively controlled by ingenious adjusting of the thickness of the PDA. The PDA-coated AIEFM (AIEFM@PDA), which not only retained the strong fluorescence of AIEFM but also improved the antibody coupling efficiency and reproducibility of LFIAs, was successfully applied in sandwich and competitive LFIAs for the highly sensitive detection of pathogenic bacteria (Escherichia coli O157:H7) and antibiotics (enrofloxacin). In comparison with the CFM method, the proposed AIEFM@PDA-LFIA for the detection of E. coli O157:H7 and enrofloxacin could enhance the sensitivity by 40 times and 20 times, respectively. In addition, AIEFM@PDA-LFIA was further used for the detection of E. coli O157:H7 in river water, apple juice, and milk with satisfactory recoveries from 82.24 to 123.02% and enrofloxacin in pork, chicken, fish, and beef with satisfactory recoveries from 75.67 to 120.89%. The proposed AIEFM@PDA-LFIA showed excellent potential in rapid detection applications.

Molecular Engineering Powered Dual-Readout Point-of-Care Testing for Sensitive Detection of Escherichia coli O157:H7

“…Synthesis and Characterization of BAPFNPs. Based on the above discussion, brilliant BAPF was applied for the preparation of nanoparticles (BAPFNPs) by the microemulsion method 23 to enable BAPF to be more suitable for actual applications (Figure 2a). When a large number of BAPFs are loaded into a single nanoparticle, the AIE effect is activated and the as-prepared BAPFNPs can be excited to emit deep-red luminescence by confocal laser scanning microscope (CLSM) (Figure S8).…”

Surface Oxygen Vacancy-Rich Co3O4 Nanowires as an Effective Catalyst of Luminol–H2O2 Chemiluminescence for Sensitive Immunoassay

“…Dopamine can self-polymerize to form PDA on the surface of most materials under weak alkaline conditions through π–π conjugation, coordination, or hydrogen bonding . Catechol groups on the surface of PAD exhibit coupling ability with biomolecules through the formation of Schiff bases and Michael-type addition. , In this work, PDA was coated on the surface of Vo-Co 3 O 4 -4 to obtain the Vo-Co 3 O 4 @PDA complex (Figure S4). We measured the FT-IR spectrum of the obtained Vo-Co 3 O 4 @PDA.…”

“…Then, Vo-Co 3 O 4 @PDA conjugated the secondary antibody (Ab 2 ) via catechol group of the PDA layer, − achieving Vo-Co 3 O 4 @PDA/Ab 2 probe (Scheme A). Dynamic light scattering was applied to characterize the Vo-Co 3 O 4 @PDA/Ab 2 probe.…”

“…41 Catechol groups on the surface of PAD exhibit coupling ability with biomolecules through the formation of Schiff bases and Michael-type addition. 42,43 In this work, PDA was coated on the surface of Vo-Co 3 O 4 -4 to obtain the Vo-Co 3 O 4 @PDA complex (Figure S4). We measured the FT-IR spectrum of the obtained Vo-Co 3 O 4 @PDA.…”

High-Performance Fluorescent Microspheres Based on Fluorescence Resonance Energy Transfer Mode for Lateral Flow Immunoassays

“…DAIEPMs were prepared by the microemulsion method following a previous study. 22 PMMA (500 mg) and PMAO (1500 mg) were predissolved in 25 mL of chloroform, and BAPF (1, 2.5, 5, 10, and 20 mg) was added to 5 mL of the above solution to obtain a stock solution. The stock solution was used to dissolve different amounts of TCBPEME (1, 5, 10, 30, and 50 mg).…”