Molecularly imprinted polymers as a selective sorbent for forensic applications in biological samples-a review

Development of a "turn off" fluorescent molecularly imprinted nanoparticle-based sensor for selective captopril quantification in synthetic urine and wastewater samples

The combination of silica nanoparticles with fluorescent molecularly imprinted polymers (Si-FMIPs) prepared by a one-pot sol-gel synthesis method to act as chemical sensors for the selective and sensitive determination of captopril is described. Several analytical parameters were optimized, including reagent ratio, solvent, concentration of Si-FMIP solutions, and contact time. Fourier-transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), and the ninhydrin assay were used for characterization. The selectivity was evaluated against molecules belonging to other drug classes, such as fluoroquinolones, nonacid nonopioids, benzothiadiazine, alpha amino acids, and nitroimidazoles. Under optimized conditions, the Si-FMIP-based sensor exhibited a working range of 1-15 µM, with a limit of detection (LOD) of 0.7 µM, repeatability of 6.4% (n = 10), and suitable recovery values at three concentration levels (98.5% (1.5 µM), 99.9% (3.5 µM), and 99.2% (7.5 µM)) for wastewater samples. The sensor provided a working range of 0.5-15 µM for synthetic urine samples, with an LOD of 0.4 µM and a repeatability of 7.4% (n = 10) and recovery values of 93.7%, 92.9%, and 98.0% for 1.0 µM, 3.5 µM, and 10 µM, respectively. In conclusion, our single-vessel synthesis approach for Si-FMIPs proved to be highly effective for the selective determination of captopril in wastewater and synthetic urine samples.

Surface molecularly imprinted polymers based on magnetic multi-walled carbon nanotubes for the highly selective purification of resveratrol from crude extracts of Vitis vinifera, Arachis hypogaea, and Polygonum cuspidatum

In this work, surface molecularly imprinted polymers based on magnetic multi-walled carbon nanotubes were prepared for the specific recognition and adsorption of resveratrol. The functionalization of magnetic multi-walled carbon nanotubes and the synthesis process of surface molecularly imprinted polymers were optimized. Characterizations were performed to demonstrate the successful synthesis of the imprinted materials. The imprinted materials showed satisfactory adsorption capacity of resveratrol (45.73 ± 1.72 mg/g) and excellent selectivity (imprinting factor 2.89 ± 0.15). In addition, the imprinted materials were used as adsorbents in molecularly imprinted solid-phase extraction for the purification of resveratrol from crude extracts of some food and medicinal resources, achieving recoveries of 93.69%-95.53% with high purities of 88.37%-92.33%. Moreover, the purified products exhibited extremely strong free radical scavenging activity compared with crude extracts. Overall, this work provided a promising approach for the highly selective purification of resveratrol from natural resources, which would contribute to the application of this valuable compound in the food/nutraceutical fields.

Application of molecular imprinting polymers in separation of active compounds from plants

Molecular imprinting technique is becoming an appealing and prominent strategy to synthesize materials for target recognition and rapid separation. In recent years, it has been applied in separation of active compounds from various plants and has achieved satisfying results. This review aims to make a brief introduction of molecular imprinting polymers and their efficient application in the separation of various active components from plants, including flavonoids, organic acids, alkaloids, phenylpropanoids, anthraquinones, phenolics, terpenes, steroids, and diketones, which will provide some clues to help stimulating research into this fascinating and useful area.

Selective extraction of synthetic cathinones new psychoactive substances from wastewater, urine and cocktail using dummy molecularly imprinted polymers

Dummy molecularly imprinted polymers (DMIPs) for selective extraction of five common synthetic cathinones (SCs) were prepared by bulk polymerization. DMIPs materials possessed narrow diameter distribution (30-60 µm) and large specific surface area (329.6 m² g^-1). Imprinting factors for cathinone, methcathinone, mephedrone, methylone and ethylone were 1.11-1.82. DMIPs could also quickly adsorb SCs from aqueous solutions within 5 min. Therefore, the materials were used as solid-phase extraction (SPE) sorbents to selectively extract five SCs in complex samples. An accurate and sensitive analytical method based on DMIPs-SPE combined with HPLC-MS/MS was established. Under optimal conditions, the established method showed low limits of detection (0.002-0.1 ng mL^-1), satisfactory recoveries (84.1-97.7%) and good repeatability (relative standard deviation (RSD) below 9%). The method was successfully verified using wastewater, urine and cocktail samples. Recoveries of SCs at three spiking levels were in the range of 75.1-98.6%, with RSD values below 7.0%. Compared with commercial sorbents, DMIPs showed better clean-up ability with matrix effect values of -24.1%-8.3% for all SCs in wastewater, urine and cocktail samples. Therefore, the developed DMIPs-SPE-HPLC-MS/MS strategy could be used as a specific and cost-effective method for sensitive determination of SCs in complex samples.

Raman and Scanning Probe Microsocopy for differentiating surface imprints of E.coli and B.cereus

Molecularly imprinted polymers (MIPs) are artificial recognition materials mimicking biological recognition entities such as antibodies. The general model of imprinting assumes that functional monomers interact with functional groups present on...