Abstract
Background: Colloidal gold based lateral flow immunoassay (LFIA) commonly suffers from relatively low detection sensitivity due to the insufficient brightness of conventional gold nanoparticles (AuNPs) with the size of 20–40 nm. Methods: Herein, three kinds of gold nanobeads (GNBs) with the size of 94 nm, 129 nm, and 237 nm, were synthesized by encapsulating numerous hydrophobic AuNPs (10 nm) into polymer matrix. The synthesized GNBs exhibited the enhanced colorimetric signal intensity compared with 20–40 nm AuNPs. The effects of the size of GNBs on the sensitivity of LFIA with competitive format were assessed. Results: The results showed that the LFIA using 129 nm GNBs as amplified signal probes exhibits the best sensitivity for fumonisin B1 (FB1) detection with a cut-off limit (for visual qualitative detection) at 125 ng/mL, a half maximal inhibitory concentration at 11.27 ng/mL, and a detection limit at 1.76 ng/mL for detection of real corn samples, which are 8-, 3.82-, and 2.89-fold better than those of conventional AuNP40-based LFIA, respectively. The developed GNB-LFIA exhibited negligible cross-reactions with other common mycotoxins. In addition, the accuracy, precision, reliability, and practicability were demonstrated by determining real corn samples. Conclusions: All in all, the proposed study provides a promising strategy to enhance the sensitivity of competitive LFIA via using the GNBs as amplified signal probes.
Highlights
Colloidal gold based lateral flow immunoassay (LFIA) is one of the most popular screening tools for on-site bio-detection by the naked-eye because of its advantages, such as simplicity, convenience, rapidity, and low cost [1,2]
The resultant gold nanobeads (GNBs) were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), and ultraviolet–visible (UV– vis) absorption spectra
The TEM images (Figure 1b) showed that all three assembled GNBs exhibited regular spheres measuring 94 ± 13, 129 ± 17, and 237 ± 21 nm, these values are slightly smaller than the hydrodynamic diameters measured by Dynamic light scattering (DLS), which were 98 ± 8, 144 ± 12, and 253 ± 16 nm, respectively
Summary
Colloidal gold based lateral flow immunoassay (LFIA) is one of the most popular screening tools for on-site bio-detection by the naked-eye because of its advantages, such as simplicity, convenience, rapidity, and low cost [1,2]. For the conventional LFIA, the presence of a red band in the detection line depends on the sufficient gold nanoparticle (AuNP) accumulation [3]. Improving the color intensity of individual probes can effectively reduce the required number of accumulated probes in the test area for enhanced sensitivity in competitive LFIA. For this purpose, various new nanomaterials with enhanced signal transducer features, such as quantum dots (QDs) [6], upconversion nanoparticles [7], dyedoped nanoparticles [8], and magnetic nanobeads [9], have been recently introduced to replace AuNPs as LFIA labels to improve the sensitivity. Conclusions: All in all, the proposed study provides a promising strategy to enhance the sensitivity of competitive LFIA via using the GNBs as amplified signal probes
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
