Microelectromechanical Microsystems-Supported Photothermal Immunoassay for Point-of-Care Testing of Aflatoxin B1 in Foodstuff

Abstract

Accurate identification of acutely toxic and low-fatality mycotoxins on a large scale in a quick and cheap manner is critical for reducing population mortality. Herein, a portable photothermal immunosensing platform supported by a microelectromechanical microsystem (MEMS) without enzyme involvement was reported for point-of-care testing of mycotoxins (in the case of aflatoxin B 1 , AFB 1 ) in food based on the precise satellite structure of Au nanoparticles. The synthesized Au nanoparticles with a well-defined, graded satellite structure exhibited a significantly enhanced photothermal response and were coupled by AFB 1 antibodies to form signal conversion probes by physisorption for further target-promoted competitive responses in microplates. In addition, a coin-sized miniature NIR camera device was constructed for temperature acquisition during target testing based on advanced MEMS fabrication technology to address the limitation of expensive signal acquisition components of current photothermal sensors. The proposed MEMS readoutbased microphotothermal test method provides excellent AFB 1 response in the range of 0.5−500 ng g −1 with detection limits as low as 0.27 ng g −1 . In addition, the main reasons for the efficient photothermal transduction efficiency of Au with different graded structures were analyzed by finite element simulations, providing theoretical guidance for the development of new Au-based photothermal agents. In conclusion, the proposed portable micro-photothermal test system offers great potential for point-of-care diagnostics for residents, which will continue to facilitate immediate food safety identification in resource-limited regions.

Hybridization Chain Reaction-Enhanced Biocatalytic Precipitation on Flower-like Bi2S3: Toward Organic Photoelectrochemical Transistor Aptasensing with High Transconductance

“…As indicated in Figure c, only PSA and the mixed-specimen caused obvious responses, even though the concentration of interfering substances was 100 times higher, suggesting a high selectivity of the aptasensor. In addition, the feasibility of the OPECT aptasensor for real-life sensing was evaluated using a standard addition method with normal human serum. , As shown in Figure d, the addition of PSA of 10, 5.0, and 1.0 pg mL –1 into the diluted serum specimens could achieve recoveries of 98.2, 97.7, and 103.4%, respectively, indicating its potential for real-world applications.…”

“…In addition, the feasibility of the OPECT aptasensor for real-life sensing was evaluated using a standard addition method with normal human serum. 41,42 As shown in Figure 5d, the addition of PSA of 10, 5.0, and 1.0 pg mL −1 into the diluted serum specimens could achieve recoveries of 98.2, 97.7, and 103.4%, respectively, indicating its potential for real-world applications.…”

Recent advances in metal–organic framework-based photoelectrochemical and electrochemiluminescence biosensors

“…Additionally, there is a growing demand for portable devices in many fields, such as rapid screening of infectious diseases, environmental monitoring, and food safety inspection. [159][160][161][162][163][164] However, MOFbased PEC and ECL biosensors are often not portable enough to meet the needs of point of care testing. To meet this unique need, combining MOF-based PEC and ECL biosensors with microfluidic technology would be an effective solution.…”

Screening of a High-Affinity Aptamer for Aflatoxin M1 and Development of Its Colorimetric Aptasensor

“…Aflatoxin M 1 (AFM 1 ) is mainly a hydroxyl derivative produced by circulating metabolism in lactating animals after ingesting feed contaminated with aflatoxin B 1 . , As a food hazard, it is widely found in milk and dairy products, moldy cereals, and meat products . When humans accidentally consume AFM 1 -contaminated food, it can cause a variety of clinical symptoms, such as vomiting and abdominal pain.…”