3D flower-like ceria silver co-doped zinc oxide catalyst assembled by nanorod for electrochemical sensing of zearalenone in food samples

Flower like ZnO hybrid mediated visible light harvesting film with upgraded photodynamic antibacterial capacity for effective food preservation

Active food packaging film with light-driven antibacterial properties has inspired numerous interests for food preservation, while efficiently retains the photocatalytic ability remains highly challenging. This study pioneered an advanced visible light-driven photodynamic antibacterial packaging film (FZ-PC) employing an organic-inorganic hybrid strategy, meticulously engineering flower-like zinc oxide functional fillers (FZnO) with superior photoactivity and subsequently formulating a polyvinyl alcohol/sodium carboxymethyl cellulose (PC) mixed film matrix to enhance its physical and chemical properties. The boosting photodynamic activity of the FZnO results from the molecular-level optimization through citral modification. Collectively, the robust electrostatic interactions with bacteria and the enhanced generation capabilities of 1O2, •O2-, and •OH equip the FZ-PC film with superior bacterial inactivation properties, which can reduce the concentrations of Salmonella enteritidis and Staphylococcus aureus by 6 and 6.3 log, respectively. Furthermore, the FZnO-PC film showed lower UV transmittance, higher water contact angle and better mechanical strength. The enhanced antibacterial behavior and improved physicochemical properties of the composite film render it an ideal solution for fruit and vegetable preservation, significantly extending the storage life of cherry tomatoes from 4 days to 11 days. These findings suggest that the developed FZnO-PC film represents a promising advancement in packaging technology.

Dual-signal ratiometric electrochemical aptasensor for Zearalenone detection based on magnetic-assisted enrichment and hybridization chain reaction

In this work, a dual-signal ratiometric electrochemical aptasensor based on the hybrid chain reaction (HCR) and streptavidin-modified magnetic beads (SA-MBs) was developed to rapidly detect zearalenone (ZEN). The HCR, as a powerful signal amplification technique to imporve the signal of sonser. When the target is present, they specifically bind with ZEN-Apt and release ZEN-cDNA to trigger HCR. Simultaneously, more double-stranded DNA causes the signal of Thi to be blocked. As a result, the two signals tend to change in the opposite direction as the ZEN concentration changes. Additionally, the peak current ratio of IThi/IFc showed a positive correlation with the ZEN concentration. Under optimal conditions, the constructed biosensor showed an excellent linear detection range (1.0 × 10-10 mol/L to 1.0 × 10-6 mol/L), a low detection limit (4.4 × 10-11 mol/L) and high specificity for ZEN. In addition, the detection method retains the characteristics of low cost and rapid detection of electrochemical detection, while improving the detection limit and detection accuracy via SA-MBs and internal reference signal. This provides a new idea for the practical detection of ZEN.

An electrochemical aptasensor for zearalenone detection based on the Co3O4/MoS2/Au nanocomposites and hybrid chain reaction

An electrochemical aptasensor was used for the fast and sensitive detection of zearalenone (ZEN) based on the combination of Co3O4/MoS2/Au nanocomposites and the hybrid chain reaction (HCR). The glassy carbon electrode was coated with Co3O4/MoS2/Au nanomaterials to immobilize the ZEN-cDNA that had been bound with ZEN-Apt by the principle of base complementary pairing. In the absence of ZEN, the HCR could not be triggered because the ZEN-cDNA could not be exposed. After ZEN was added to the surface of the electrode, a complex structure was produced on the modified electrode by the combination of ZEN and ZEN-Apt. Therefore, the ZEN-cDNA can raise the HCR to produce the long-strand dsDNA structure. Due to the formation of dsDNA, the methylene blue (MB) could be inserted into the superstructure of branched DNA and the peak currents of the MB redox signal dramatically increased. So the concentration of ZEN could be detected by the change of signal intensity. Under optimized conditions, the developed electrochemical biosensing strategy showed an outstanding linear detection range of 1.0×10-10 mol/L to 1.0×10-6 mol/L, a low detection limit (LOD) of 8.5×10-11 mol/L with desirable selectivity and stability. Therefore, the fabricated platform possessed a great application potential in fields of food safety, medical detection, and drug analysis.

Recent progress in the synthesis and applications of covalent organic framework-based composites

Covalent organic frameworks (COFs) have historically been of interest to researchers in different areas due to their distinctive characteristics, including well-ordered pores, large specific surface area, and structural tunability. In the past few years, as COF synthesis techniques developed, COF-based composites fabricated by integrating COFs and other functional materials including various kinds of metal or metal oxide nanoparticles, ionic liquids, metal-organic frameworks, silica, polymers, enzymes and carbon nanomaterials have emerged as a novel kind of porous hybrid material. Herein, we first provide a thorough summary of advanced strategies for preparing COF-based composites; then, the emerging applications of COF-based composites in diverse fields due to their synergistic effects are systematically highlighted, including analytical chemistry (sensing, extraction, membrane separation, and chromatographic separation) and catalysis. Finally, the current challenges associated with future perspectives of COF-based composites are also briefly discussed to inspire the advancement of more COF-based composites with excellent properties.