Light-Activated Interface Charge-Alternating Interaction on an Extended Gate Photoelectrode: A New Sensing Strategy for EGFET-Based Photoelectrochemical Sensors

Antibiotic residue detection by novel photoelectrochemical extended-gate field-effect transistor sensor

Residual antibiotics in the environment may pose threats to both ecological system and public health, necessitating the development of efficient analytical strategy for monitoring and control. This study proposes a photoelectrochemical extended-gate field-effect transistor (PEGFET) sensor for specific and sensitive detection of kanamycin. The sensor utilizes ITO glass as the extended gate electrode (photoelectrode) and titanium dioxide as the photosensitive material. It leverages the interaction between kanamycin and its corresponding aptamer to influence the ability of gold nanocluster to catalyze the oxidation of 3,3'-diaminobenzidine (DAB). This interaction results in different amounts of DAB precipitate on the photoelectrode surface, leading to gate voltage shift and source-drain current response. This sensing platform achieves trace detection of kanamycin with a limit of detection (LOD) at nM level and a wide linear detection range from 10 nM to 100 μM. The results demonstrate that the PEGFET with incorporated photoelectrochemical process can significantly enhance the sensitivity of traditional EGFET sensor, and the photoelectric signal originates from the change in electron transfer ability of the photoelectrode. The reported PEGFET with photo-responsive extended gate presents a new and promising structure in FET sensor design for enhanced detection performances in chemical and biological sensing.

(Bio)Electroanalysis of Tetracyclines: Recent Developments

Tetracyclines (TCs) are antibiotics used extensively in medicine, veterinary science, and animal husbandry. Their overuse and the widespread presence of their residues in the environment contribute to intensifying the phenomenon of antibiotic resistance (ABR). The efforts are being made to reduce the spread of antibiotics and control the phenomenon of ABR, and one of the key methods is monitoring the presence of antibiotic residues in the environment and food of animal origin. Herein, we provide the overview of the recent developments in electrochemical (bio)sensing of tetracyclines in different types of samples. The review presents a comprehensive view of such aspects of the practical (bio)sensor application as sample preparation, the reusability of (bio)sensors, and the possibility of determining antibiotics at levels required by regulations. Advances, existing challenges, and future trends in the development of novel (bio)electrochemical methods of tetracycline quantification were discussed.

Synergistic effect of 2D covalent organic frameworks confined 0D carbon quantum dots film: Toward molecularly imprinted cathodic photoelectrochemical platform for detection of tetracycline

The development of high photoactive cathode materials combined with the formation of a stable interface are considered important factors for the selective and sensitive photoelectrochemical (PEC) detection of tetracycline (TC). Along these lines, in this work, a novel type II heterostructure composed of two-dimensional (2D) covalent organic frameworks confined to zero-dimensional (0D) carbon quantum dots (CDs/COFs) film was successfully synthesized using the rapid in-situ polymerization method at room temperature. The PEC signal of CDs/COFs was significantly amplified by improving the light absorption and electron transfer capabilities. Furthermore, a cathodic molecularly imprinted PEC sensor (MIP-PEC) for the detection of TC was constructed through fast in-situ Ultraviolet (UV) photopolymerization on the electrode. Finally, a "turn-off" PEC cathodic signal was achieved based on the selective recognition of the imprinted cavity and the mechanism of steric hindrance increase. Under optimal conditions, the proposed sensor demonstrated a wide linear relationship with TC in the concentration range of 5.00 × 10-12-1.00 × 10-5 M, with a detection limit as low as 6.00 × 10-13 M. Meanwhile, excellent stability, selectivity, reproducibility, and applicability in real river samples was recorded. Our work provides an effective and rapid in situ construction method for fabricating highly photoactive cathode heterojunctions and uniform stable selective MIP-PEC sensing interfaces, yielding accurate antibiotics detection in the environment.

Recent Advances in Tactile Sensory Systems: Mechanisms, Fabrication, and Applications

Flexible electronics is a cutting-edge field that has paved the way for artificial tactile systems that mimic biological functions of sensing mechanical stimuli. These systems have an immense potential to enhance human-machine interactions (HMIs). However, tactile sensing still faces formidable challenges in delivering precise and nuanced feedback, such as achieving a high sensitivity to emulate human touch, coping with environmental variability, and devising algorithms that can effectively interpret tactile data for meaningful interactions in diverse contexts. In this review, we summarize the recent advances of tactile sensory systems, such as piezoresistive, capacitive, piezoelectric, and triboelectric tactile sensors. We also review the state-of-the-art fabrication techniques for artificial tactile sensors. Next, we focus on the potential applications of HMIs, such as intelligent robotics, wearable devices, prosthetics, and medical healthcare. Finally, we conclude with the challenges and future development trends of tactile sensors.

Oxygen Vacancies-Induced Antifouling Photoelectrochemical Aptasensor for Highly Sensitive and Selective Determination of α-Fetoprotein

Accurate measurement of cancer markers in urine is a convenient method for tumor monitoring. However, the concentration of cancer markers in urine is so low that it is difficult to achieve their measurement. Photoelectrochemical (PEC) sensors are a promising technology to realize the detection of trace cancer markers due to their high sensitivity. Currently, the interference of nonspecific biomolecules in urine is the main reason affecting the high sensitivity and selectivity of PEC sensors in detecting cancer markers. In this work, a strategy of oxygen vacancy (OV) modulation is proposed to construct a fouling-resistant PEC aptamer sensing platform for the detection of α-fetoprotein (AFP), a liver cancer marker. The introduction of OVs induces the formation of intermediate localized states in the photoelectric material, which not only facilitates the separation of photogenerated carriers but also leads to the redshift of the light absorption edge. More importantly, OVs with positive electrical properties can be employed to modify the antifouling layer (C-PEG) with negatively charged groups through an electrostatic interaction. The synergistic effect of OVs, antifouling layer, and aptamer resulted in a TiO2/OVs/C-PEG-based PEC sensor achieves a wide linear range from 1 pg/mL to 100 ng/mL and a low detection limit of 0.3 pg/mL for AFP. In addition, the sensor successfully realized the determination of AFP in urine samples and accurately differentiated between normal people and liver cancer patients in the early and advanced stages. This project is of great significance in advancing the application of photoelectrochemical bioanalytical technology to achieve the detection of cancer markers in urine by investigating the construction of an OVs-regulated fouling-resistant sensing interface.