Ascribing to the abundance of Ti element, exceptional electrical conductivity, and electrocatalytic performance, titanium carbide MXene (Ti3C2Tx, MX) is considered as an ideal conductive matrix and employed for in situ preparation of promising TiO2 NPs@MX/reduced graphene oxide (rGO) heterojunction electrodes for uric acid (UA) detection. However, the incapability of achieving the controllable growth and synthesis of TiO2 nanoparticles (NPs) on MX nanosheets is a bottleneck in fabricating optimal and controllable TiO2 NPs@MX hybrid. Herein, an “on‐site transformation strategy” is developed to synthetize TiO2 NPs@MX/rGO heterojunction platform controllably by in situ electrochemical oxidizing MX nanosheets at various treatment times. The proposed approach allows for the greater operability to controllably grow and synthetize TiO2 NPs on the surface of MX nanosheets. The heterojunction electrodes present a linear voltammetric response toward UA in the concentration range of 0.003–0.3 and 0.3–300 μm and a low detection limit of 0.78 nm (S/N = 3). Additionally, a handheld electrochemical system with a smartphone readout is developed for point‐of‐care health monitoring, enabling fast, precise, and specific recognition of UA in real urine samples. The study provides a facile and controllable approach to fabricate TiO2 NPs@MX/rGO heterojunction platform for future use in other biomolecules' detection.
Recent advancements in polymer-assisted layer-by-layer (LbL) fabrication have revolutionized the development of wearable sensors for health monitoring. LbL self-assembly has emerged as a powerful and versatile technique for creating conformal, flexible, and multi-functional films on various substrates, making it particularly suitable for fabricating wearable sensors. The incorporation of polymers, both natural and synthetic, has played a crucial role in enhancing the performance, stability, and biocompatibility of these sensors. This review provides a comprehensive overview of the principles of LbL self-assembly, the role of polymers in sensor fabrication, and the various types of LbL-fabricated wearable sensors for physical, chemical, and biological sensing. The applications of these sensors in continuous health monitoring, disease diagnosis, and management are discussed in detail, highlighting their potential to revolutionize personalized healthcare. Despite significant progress, challenges related to long-term stability, biocompatibility, data acquisition, and large-scale manufacturing are still to be addressed, providing insights into future research directions. With continued advancements in polymer-assisted LbL fabrication and related fields, wearable sensors are poised to improve the quality of life for individuals worldwide.
Bisphenol A (BPA) is an industrial chemical used extensively in plastics and resins. However, its endocrine-disrupting properties pose risks to human health and the environment. Thus, accurate and rapid detection of BPA is crucial for exposure monitoring and risk mitigation. Molecularly imprinted electrochemical sensors (MIES) have emerged as a promising tool for BPA detection due to their high selectivity, sensitivity, affordability, and portability. This review provides a comprehensive overview of recent advances in MIES for BPA detection. We discuss the operating principles, fabrication strategies, materials, and methods used in MIES. Key findings show that MIES demonstrate detection limits comparable or superior to conventional methods like HPLC and GC-MS. Selectivity studies reveal excellent discrimination between BPA and structural analogs. Recent innovations in nanomaterials, novel monomers, and fabrication techniques have enhanced sensitivity, selectivity, and stability. However, limitations exist in reproducibility, selectivity, and stability. While challenges remain, MIES provide a low-cost portable detection method suitable for on-site BPA monitoring in diverse sectors. Further optimization of sensor fabrication and characterization will enable the immense potential of MIES for field-based BPA detection.
Chloramphenicol (CAP) is a harmful compound associated with human hematopathy and neuritis, which was widely used as a broad-spectrum antibacterial agent in agriculture and aquaculture. Therefore, it is significant to detect CAP in aquatic environments. In this work, carbon nanotubes/silver nanowires (CNTs/AgNWs) composite electrodes were fabricated as the CAP sensor. Distinguished from in situ growing or chemical bonding noble metal nanomaterials on carbon, this CNTs/AgNWs composite was formed by simple solution blending. It was demonstrated that CNTs and AgNWs both contributed to the redox reaction of CAP in dynamics, and AgNWs was beneficial in thermodynamics as well. The proposed electrochemical sensor displayed a low detection limit of up to 0.08 μM and broad linear range of 0.1–100 μM for CAP. In addition, the CNTs/AgNWs electrodes exhibited good performance characteristics of repeatability and reproducibility, and proved suitable for CAP analysis in real water samples.