Gold Nanobipyramid-Based Photothermal Immunoassay for Portable Detection of Ochratoxin A in Maize and Grape Juice

Abstract

Gold nanobipyramids (AuNBPs) have made great progress in photothermal application due to their prominent photothermal conversion ability, but they have not been applied in the field of photothermal immunoassay. Herein, we employ alkaline phosphatase (ALP) to mediate the in situ growth of AuNBPs to construct a convenient photothermal immunoassay method that can achieve portable detection of ochratoxin A (OTA) by using a thermometer. The integration of the classical tyramine signal amplification strategy with the ALP enzymatic reaction enables this photothermal ELISA to detect OTA sensitively with a detection limit of 0.20 ng mL −1 . The practicability of this photothermal immunoassay method is demonstrated by analyzing OTA spiked in maize and grape juice samples. The good performance of this photothermal method indicates the applicability of AuNBPs in the photothermal immunoassay. Additionally, the implementation of this photothermal method does not need any large-scale instruments, which provides a promising method for OTA on-site detection.

Gold Nanobipyramid-Based Photothermal Sensors for the Portable Evaluation of Total Antioxidant Capacity

“…As one of the most familiar physical quantities, temperature is easily measured using portable devices, such as thermometers or thermal-imaging cameras. , Utilizing these portable devices for readouts, photothermal analytical methods that convert molecular concentration information into temperature values have garnered considerable interest. , Photothermal materials play a pivotal role in developing photothermal sensors. Because of their straightforward synthesis, convenient modification, excellent dispersibility, high extinction coefficient, and outstanding stability, gold nanocrystals have become a focus of attention in photothermal sensors. , Notably, the photothermal conversion efficiency of gold nanocrystals is intricately linked to their local surface plasmon resonance (LSPR) peak, a characteristic determined by various factors, such as size, morphology, surface composition, dispersion state, and surrounding media .…”