Core-shell Au@PdNPs based colorimetric enhanced lateral flow immunoassay for C-reactive protein detection

Benefiting from many advantages including low cost, simple operation and low dependence on analytical in-struments, lateral flow immunoassay (LFIA) has been widely used in many fields such as food detection, envi-ronmental monitoring, disease diagnosis, etc., but the lack of sensitivity is still the main problem to be solved. Here, a simply prepared core-shell Au@PdNPs was used to displace the commonly used AuNPs to construct the colorimetric enhanced LFIA. As a label with high peroxidase-like activity, Au@PdNPs can further catalyze the oxidation and color conversion of TMB to obtain more significant visual signals. By using a high-viscosity chromogenic agent to reduce the diffusion and migration of colored products, another problem affecting the observation of testing results was also well solved. As a result, in the case of detecting C-reactive protein with important clinical diagnostic value, the limit of detection (0.32 ng/mL) was improved by about 62 times through additional 30 s of coloration. Considering its good performance in the detection of serum-containing samples, the proposed colorimetric enhanced LFIA provides an effective means for sensitive detection of low-concentration targets, which is worthy of further promotion and will play an important role in more clinical diagnostics.

Automated summary

By using core-shell Au@PdNPs with high peroxidase-like activity, the colorimetric enhanced LFIA improved the sensitivity and detection limit for low-concentration targets. The use of a high-viscosity chromogenic agent also solved the problem of observation of testing results. This improved LFIA method has potential in clinical diagnostics and should be further promoted.