Henan University of Technology

Curcumin is extensively existed in plants and is commonly used as food additives. However, excessive intake of curcumin may lead to side effects like nausea and vomiting. Traditional techniques such as high-performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrometry (LC-MS) are constrained by cumbersome operations and low efficiency. Herein, a triple-emission surface molecularly imprinted fluorescence sensor (TPP&RhB-SMIPs) was fabricated via precipitation polymerization on halloysite nanotubes (HNTs), using aggregation-induced emission luminogen (AIEgen) TPP-M and allyl rhodamine B as fluorophores. This sensor exhibits distinct fluorescence color transitions (purple-fuchsia-carnation-yellow-chartreuse) with increasing curcumin concentrations, coupled with a linear range of 0.1-4.0 μmol L^-1 and a low detection limit of 44 nmol L^-1. It demonstrates excellent selectivity and achieves satisfactory recoveries in ginger and beverage samples. A smartphone-integrated portable device was further developed for on-site visual detection of curcumin. This work provides a reliable, rapid, and cost-effective strategy for curcumin analysis, holding great promise for food safety monitoring.

Adenosine triphosphate (ATP) is a widely recognized indicator of microbial contamination, and its rapid and accurate detection is essential for assessing microbial pollution in food safety. Herein, an electrochemical aptasensor integrating a dual-signal amplification strategy was developed for ultrasensitive detection of ATP. Platinum-palladium/graphitic carbon nitride (PtPd NPs/g-C₃N₄) was used as the electrode-modification material, improving the conductivity and electroactive surface area while providing a favorable platform for biomolecular immobilization. Additionally, an aptamer-regulated DNAzyme locking strategy was introduced for signal control, in which the DNAzyme was initially inactivated through hybridization with two aptamer sequences. Upon ATP binding, the aptamers undergo conformational changes and dissociate from the DNAzyme, thereby restoring its catalytic activity. The activated DNAzyme subsequently catalyzes the cyclic cleavage of substrate DNA strands on the electrode surface in the presence of Mg²⁺, leading to significant signal amplification. Under optimized conditions, the constructed aptasensor exhibited excellent analytical performance, with a linear range from 10 pM to 10 μM and a low detection limit of 1.71 fM. Moreover, the sensor demonstrated good selectivity, stability, and reproducibility, and was successfully applied to ATP detection in beer samples. This strategy provides a sensitive approach for trace ATP analysis and shows potential for applications in food safety analysis.

The development of high-performance magnetic carrageenan/mesona gum (CMG) hydrogel-based soft actuators that integrate rapid response, autonomous motion, and real-time sensing capabilities remains a significant challenge. Inspired by the muscle fiber structure, a hamburger-like conductive composite is presented that achieved a synergistic combination of high biocompatibility, high-speed, integrated magnetic actuation and self-sensing functionality via an eco-friendly fabrication strategy. The magnetic actuation hydrogel exhibits excellent flexibility and magnetically actuated capability attributed to the gradient distribution of magnetic particles (MPs)@multi-walled carbon nanotube (MWCNTs) within the CMG interpenetrating network. Meanwhile, benefiting from the satisfied electrochemical performance, the MWCNTs/sodium alginate (SA) electrodes on both sides enhance the electrical responsiveness and reliability to external stimuli. The developed device demonstrates satisfied biocompatibility, high strain sensitivity (gauge factor of 3.06), fast response (107 ms), remarkable cycling durability (6000 cycles), and rapid magnetic actuation speed of 26.7°/s. The core achievement is that the co-localization of actuation and sensing within a monolithic structure, which allows simultaneous actuated deformation and real-time motion monitoring. This has been demonstrated in bio-inspired systems, including a gripper capable of detecting its own position and grip, and a fish-like actuator that can monitor its own movement. Therefore, this work offers a novel strategy and inspiration for designing intelligent flexible actuation with self-feedback loops, displaying great potentials in next-generation wearable electronics, soft bionic robots, and human-machine interaction.