Construction of a Biomimetic Receptor Based on Hydrophilic Multifunctional Monomer Covalent Organic Framework Molecularly Imprinted Polymers for Molecular Recognition of Cyanidin-3-O-Glucoside

Molecularly imprinted polymer combined with multiple-component covalent organic frameworks for extraction of naringenin enantiomers

Naringenin is a plant flavonoid found in citrus fruits and is known for its anti-inflammatory and antioxidant activities. However, extracting high-purity naringenin from citrus fruits and separating its enantiomers remains challenging. This study synthesized a molecularly imprinted multiple-component covalent organic framework (MI COF) with abundant imprinted recognition sites for the first time. This MI COF combines the advantages of molecular imprinting and covalent organic frameworks into an innovative adsorbent capable of specifically recognizing and efficiently adsorbing naringenin. MI COF exhibited an excellent adsorption capacity of 121 mg/g and a superior selectivity with an imprinting factor of 2.8 for naringenin. As a result, remarkably selective extraction of naringenin from citrus fruit extracts was achieved, with recoveries and purities of 85.7 % and 87.5 %, respectively. In addition, the vitro immunological and anticancer activities of naringenin enantiomers from citrus fruit was preliminarily investigated. These findings demonstrate that MI COF is an effective sorbent for the selective adsorption and separation of naringenin and its enantiomers from plants and fruits, holding significant potential for practical applications in food and clinical fields.

Photocatalytic Organic Semiconductor-Bacteria Imprinted Polymers for Highly Selective Determination of Staphylococcus aureus at the Single-Cell Level

This work utilized a combination of photocatalytic organic semiconductors and bacteria to create a photocatalytic organic semiconductor-bacterial biomixture system based on a bacteria imprinted polymers (OBBIPs-PEC) sensor, for the detection of S. aureus with high sensitivity in "turn-on" mode at the single-cell level. This outstanding sensor arises from an integration of two different types of semiconductor materials to form heterojunctions. As well this sensor involves combining a semiconductor material with cationic side chains and an electron transport chain within a natural cellular environment, in which the cationic side chain of poly(fluorene-co-phenylene) organic semiconductor at 2-(4-mesyl-2-nitrobenzoyl)-1,3-cyclohexanedione (PFP-OC@MNC) demonstrated the ability to penetrate the cell membrane of S. aureus and interact with specific binding sites through electrostatic interactions. As the cavities in the BIPs were occupied by S. aureus, during light irradiation, the electrons stimulated by the photoexcitation process in the manufactured PFP-OC@MNC semiconductors were successfully transmitted to S. aureus, where these electrons played a role in the regeneration of NADH and FADH2, and then the presence of S. aureus acted as a proficient electron acceptor for photoexcited electrons; thereby the PEC response of the OBBIPs-PEC sensor was significantly enhanced. Of note, it exhibited high selectivity for S. aureus over other bacteria and maintained excellent performance in complex matrices, distinguishing S. aureus with concentrations as low as 10 CFU/mL. This work dramatically reduces the influence of interference factors in the traditional mode and offers a powerful way for microorganism detection in food and environmental fields.

Pore Size Adjustment Strategy for the Fabrication of Molecularly Imprinted Covalent Organic Framework Nanospheres at Room Temperature for Selective Extraction of Zearalenone in Cereal Samples

Covalent organic frameworks (COFs) are attractive adsorbents for sample pretreatment due to their unique structure and properties. However, the selectivity of COFs for the extraction of hazardous compounds is still limited due to the lack of specific interactions between COFs and targets. Herein, we report a pore size adjustment strategy for room-temperature synthesis of molecularly imprinted COF (MICOF) for selective extraction of zearalenone (ZEN) in complex food samples. The three-dimensional building block tetra(4-aminophenyl) methane was used as a functional monomer, while dialdehyde monomers with different numbers of benzene ring were used to adjust the pore size of MICOF to match with the size of ZEN molecules. The prepared MICOF gave the largest adsorption capacity of 177.2 mg g-1 and the highest imprinting factor of 10.1 for ZEN so far. MICOF was used as the adsorbent for dispersed solid-phase extraction in combination with high-performance liquid chromatography for the determination of trace ZEN in cereals. The high selectivity of the developed method allows simple aqueous standard calibration for the matrix effect-free determination of ZEN in food samples. The limit of detection and the recoveries of the developed method were 0.21 μg kg-1 and 93.7-101.4%, respectively. The precision for the determination of ZEN was less than 3.8% (RSD, n = 6). The developed method is promising for the selective determination of ZEN in complex matrices.