Aluminium-copper-mesoporous silica molecular sieve-enabled dual-signal point-of-care aptasensor with integrated temperature and multicolor readout

Abstract

Dual-signal point-of-care testing (POCT) method relying on multicolor changes have demonstrated a promising improvement in performance. In this work, we have developed a highly sensitive and rapid POCT method for detecting aflatoxin B1 (AFB1), utilizing a dual-signal readout mode based on temperature and multicolor changes. A synthetic enzyme mimics, Al-Cu-Santa Barbara Amorphous material (Al-Cu-SBA), has been used to enable the dual-signal changes of gold nanobipyramids (Au NBPs) for the first time. Specifically, the aptamer was immobilized on magnetic beads, facilitating hybridization with complementary strands functionalized with Al-Cu-SBA and hence forming double-stranded DNA. Upon introducing AFB1 into the system, it bound to the aptamer chain, resulting in the release of Al-Cu-SBA into solution. The liberated Al-Cu-SBA was subsequently collected and used to oxidize 3, 3′, 5, 5′-tetramethylbenzidine (TMB). The oxidized TMB was used to etch Au NBPs, inducing significant color changes. Meanwhile, by leveraging the photothermal properties of Au NBPs, we observed a temperature difference generated upon exposure to infrared laser irradiation. This method exhibited a linear range from 0.5 μg·mL−1 to 100 μg·mL−1, with a detection limit of 0.167 μg·mL−1. The method’s applicability was extended to successfully detect AFB1 in both peanut oil and milk samples. Given the application of enzyme mimics and the dual-signal readout integrating temperature and multicolor changes, our study successfully overcomes the limitations inherent in traditional biological enzyme-based methods and the conventional single-signal readout approach. Additionally, it surpasses the limitations associated with dual-signal readout systems that rely solely on monochromatic colorimetric analysis.