A Silver-Loaded Exfoliated Graphite Nanocomposite Anti-Fouling Electrochemical Sensor for Bisphenol A in Thermal Paper Samples

An ultrasensitive electrochemical biosensor for bisphenol A based on aptamer-modified MrGO@AuNPs and ssDNA-functionalized AuNP@MBs synergistic amplification

Bisphenol A (BPA) is a harmful endocrine disruptor, sensitive and rapid quantification of BPA is highly desirable. In this work, a novel synergistic signal-amplifying electrochemical biosensor was developed for BPA detection by using a recognition probe (RP) constructed by BPA aptamer modified gold nanoparticles-loaded magnetic reduced graphene oxide (Aptamer-MrGO@AuNPs), and a signal probe (SP) constructed by BPA aptamer-complementary single-stranded DNA (ssDNA) functionalized methylene blue (MB)-loaded gold nanoparticle (ssDNA-AuNP@MBs). The RP and SP can self-assemble to form a stable RP-SP complex through complementary base pairing. The current intensity of the biosensor correlates with the number of RP-SP complexes. In the presence of BPA, the BPA aptamer can capture BPA with high selectivity and affinity, form an RP-BPA complex and dissociate the RP-SP complex to release SP, resulting in a decrease in the current signal intensity of the biosensor. A single AuNP could be loaded with multiple BPA aptamers and MBs, which improves the recognition efficiency and enhances the signal intensity. Due to the magnetic properties of MrGO@AuNPs, the magnetic separation and adsorption of RP or RP-SP complex is very convenient, enabling all reaction processes to be carried out in solution, which not only improves the mass transfer efficiency, but also simplifies the operation. Under optimal conditions, the developed biosensor had a detection limit as low as 0.141 pg/mL and had been successfully applied to the detection of real environmental water samples. Therefore, the synergistic signal amplification strategy of RP and SP has potential value in the detection of trace pollutants in the water environment.

Flexible Electrochemical Platform Coupled with In Situ Prepared Synthetic Receptors for Sensitive Detection of Bisphenol A

A flexible electrochemical sensor based on the carbon felt (CF) functionalized with Bisphenol A (BPA) synthetic receptors was developed. The artificial Bisphenol A receptors were grafted on the CF by a simple thermal polymerization molecular imprinting process. Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and electrochemical characterizations were used to analyze the receptors. Characterization results demonstrated that the Bisphenol A synthetic receptors successfully formed on the CFs surface. Because the synthetic receptor and the porous CFs were successfully combined, the sensor displayed a better current response once Bisphenol A was identified. The sensor's linear range was determined to be from 0.5 to 8.0 nM and 10.0 to 300.0 nM, with a detection limit of 0.36 nM. Even after being bent and stretched repeatedly, the electrode's performance was unaffected, demonstrating the robustness, adaptability and viability of installing the sensor on flat or curved surfaces for on-site detection. The designed electrochemical sensor has been used successfully to identify Bisphenol A in milk samples with satisfactory results. This work provided a promising platform for the design of implantable, portable and miniaturized sensors.

Electrochemical sensors based on carbon nanostructures for the analysis of bisphenol A-A review

Overuse of Bisphenol A (BPA), a proven endocrine disruptor, has become a serious public health problem across the world. It has the potential to harm both the environment and human health, notably reproductive disorders, heart disease, and diabetes. Accordingly, much attention has been paid to the detection of BPA to promote food safety and environmental health. Carbon based nanostructures have proven themselves well in a variety of applications, such as energy storage, catalysis and sensors, due to their remarkable properties. Therefore, researchers have recently focused on fabricating electrochemical BPA sensors based on carbon nanostructures due to their unique advantages, such as real-time monitoring, simplicity, high selectivity, high sensitivity and easy operation. The purpose of the current review was to summarize the recent findings on carbon nanostructures for electrochemically sensing the BPA, as well as relevant future prospects and ongoing challenges.

Ratiometric electrochemical sensor for bisphenol A detection using a glassy carbon electrode modified with a poly(toluidine blue)/gold nanoparticle composite

A ratiometric electrochemical sensor for bisphenol A (BPA) detection is developed using a glassy carbon electrode modified with a poly(toluidine blue)/gold nanoparticle composite (PTB/AuNP/GCE). The ratiometric signal, namely, the oxidation peak current ratio of BPA to PTB, increases linearly with BPA concentration in the 0.2-5.0 μM range, with a detection limit of 0.15 μM. The electrochemical mechanism of BPA is studied at the PTB/AuNP/GCE, and the results show that BPA undergoes an electrooxidation process of two electrons and two protons at the PTB/AuNP/GCE. The proposed sensor has high sensitivity, high stability and good selectivity. The application of BPA in water samples is successfully verified using the proposed ratiometric electrochemical sensor.