Design Of Molecularly Imprinted Polymers Research Articles

Development of a molecularly imprinted polymer for pyridoxine using an ion-pair as template

One of the main challenges in the molecularly imprinted polymers (MIP) field is the proper MIP design for water-soluble compounds because of appearance of serious drawbacks in polar solvents and insolubility of those compounds in non-polar solvents which are commonly used for MIP synthesis. In this work a novel and simple method for synthesis of molecularly imprinted polymers for a water-soluble compound was introduced. Pyridoxine was chosen as a target molecule and the ion-pair complex formed between pyridoxine ion (Py +) and dodecyl sulfate ion (DS −) was transferred into the chloroform via liquid–liquid extraction. Then polymerization was carried out in chloroform. The molecular mechanics and density functional theory were proposed to screen proper monomer. Binding energy, Δ E, of a template and a monomer as a measure of their interaction was considered. Ion-pair [Py +-DS −] was supposed as a template molecule and acrylic acid, methacrylic acid, allyamine, vinylpridine and 2-hydroxy ethyl methacrylate were as tested monomers. The MIP synthesized using acrylic acid showed the highest selectivity to pyridoxine as predicted from the Δ E calculation. The obtained MIP showed very high affinity against vitamin B6 in comparison to non-imprinted polymers (NIP). It was proved that the obtained MIP with introduced method was much better than that prepared in methanol as porogen. It was showed that the MIP prepared by this new method could be used as an adsorber for extraction and determination of pyridoxine in real and synthetic samples.

Application of molecular dynamics modeling for the prediction of selective adsorption properties of dimethoate imprinting polymer

Abstract The selective adsorption properties of dimethoate imprinting polymers were studied by computational and conformational methods at molecular level through a molecular dynamics (MD) simulation. The MD modeling was carried out for different molecular systems to investigate the recognition mechanism by predicting the interaction energy differences and indicating the active site groups. The MD simulation was confirmed through chromatographic evaluation of dimethoate on the molecularly imprinted polymer (MIP) and non-imprinted polymer (NIP) columns. Both MD modeling and chromatographic evaluations show that the MIP based on butyl methacrylate (BMA) functional monomer had the best selective recognition for dimethoate compared to other functional monomers including methyl methacrylate (MMA) and ethyl methacrylate (EMA). Two parameters, the imprinting factor indicator (IFindicator) and the competitive factor indicator (CFindicator), were defined according to the interaction energy difference to give an insight into the imprinting selectivity of MIP to dimethoate versus other structurally related organophosphorus pesticides (OPs). The influences of the rebinding solvents on the adsorption properties of MIP were also investigated. It was found that a good rebinding solvent should have less affinity with both template and polymer and a good solubility, and a large self-association among solvent molecules could enhance the affinity between template and MIP. The results of MD simulation were comparatively in good agreement with those of chromatographic evaluation, and indicated the MD simulation could be an effective tool for the design of MIP.

Discovery and Development of OMNiMIPs: One MoNomer Molecularly Imprinted Polymers

AbstractThere is enormous potential for the analytical applications of molecularly imprinted polymers (MIPs); for example, the imprinted polymer sites can function as the molecular recognition element of sensors, immunoassays, and separation media. However, difficulties with formulation variables and the need for empirical optimization have inhibited the widespread use of MIPs by the general scientific community. While investigating new crosslinkers for molecular imprinting, we have recently discovered a much simpler approach to MIP formation which utilizes a single crosslinking monomer, NOBE (N, Obismethacryloyl ethanolamine) in addition to template, solvent and initiator (shown in Scheme 1). We have given this molecular imprinting method the acronym “OMNiMIPs” which stands for one monomer molecularly imprinted polymers. This new formulation eliminates variables such as choice of functional monomer (FM) and crosslinker (XL), the ratio of functional monomer to crosslinker (FM/XL), and the ratio of functional monomer to template which normally complicates MIP design. The affects of OMNiMIP performance variables toward molecular recognition indicate significant differences between these new materials and traditional MIPs formulated with ethyleneglycol dimethacrylate (EGDMA) and methacrylic acid (MAA). These differences and the utility of OMNiMIPs will be discussed.

Molecularly imprinted polymers in clinical diagnostics—Future potential and existing problems

The last five years have witnessed a fast progress in the area of molecularly imprinted polymers (MIPs). These have included the development of rational protocols for polymer design (combinatorial and computational), the development of MIPs compatible for use in aqueous environment and the development of various procedures for the integration of MIPs with sensors. The substantial improvements in the performance of imprinted polymers have also been accompanied by a growing number of MIP publications related to solving practical problems associated with their use, e.g. in environmental and clinical analysis. This paper furnishes a detailed analysis of recent achievements in MIPs design and applications related to healthcare, made by our group as well as others worldwide.

Molecularly Imprinted Polymers Based on Iodinated Monomers for Selective Room-Temperature Phosphorescence Optosensing of Fluoranthene in Water

Aiming at enhancing the advantages of traditional molecularly imprinted polymers (MIPs) for chemical sensing, a new MIP design approach introducing an internal heavy atom in their polymeric structure is described. Based on the heavy-atom effect, the novel polymer allows one to perform room-temperature phosphorescence (RTP) transduction of the analyte. The synergic combination of a tailor-made MIP recognition with a selective RTP detection is a novel concept for optosensing devices which is assessed here for simple and highly selective determination of trace amounts of fluoranthene in water. The noncovalent MIP was synthesized using the laboratory-synthesized tetraiodobisphenol A as one of the polymeric precursors and fluoranthene as template. In the presence of an oxygen scavenger, the iodide included in the polymeric structure induced efficient RTP emission from the analyte, once recognized by the MIP. The developed optosensing system has demonstrated a high specificity for fluoranthene against other polycyclic aromatic hydrocarbons. Detection limit for the target molecule was 35 ng/L (5-mL sample injections), and the linear range extended above 100 microg/L of the analyte. The polymer can be easily regenerated for subsequent sample injections (at least up to 450 cycles) with acetonitrile. The synthesized sensing material showed good stability for at least 6 months after preparation. The feasibility of monitoring fluoranthene in real samples was successfully evaluated through the analysis of five spiked river water samples.

Molecularly Imprinted Polymers—Potential and Challenges in Analytical Chemistry

AbstractFor Abstract see ChemInform Abstract in Full Text.

Molecularly imprinted polymers—potential and challenges in analytical chemistry

Among the variety of biomimetic recognition schemes utilizing supramolecular approaches molecularly imprinted polymers (MIPs) have proven their potential as synthetic receptors in numerous applications ranging from liquid chromatography to assays and sensor technology. Their inherent advantages compared to biochemical/biological recognition systems include robustness, storage endurance and lower costs. However, until recently only few contributions throughout the relevant literature describe quantitative analytical applications of MIPs for practically relevant analyte molecules and real-world samples. Increased motivation to thoroughly evaluate the true potential of MIP technology is clearly attributed to the demands of modern analytical chemistry, which include enhanced sensitivity, selectivity and applicability of molecular recognition building blocks at decreasing costs. In particular, the areas of environmental monitoring, food and beverage analysis and industrial process surveillance require analytical tools capable of discriminating chemicals with high molecular specificity considering increasing numbers of complex environmental contaminants, pollution of raw products and rigorous quality control requested by legislation and consumer protection. Furthermore, efficient product improvement and development of new products requires precise qualitative and quantitative analytical methods. Finally, environmental, food and process safety control issues favor the application of on-line in situ analytical methods with high molecular selectivity. While biorecognition schemes frequently suffer from degrading bioactivity and long-term stability when applied in real-world sample environments, MIPs serving as synthetic antibodies have successfully been applied as stationary phase separation matrix (e.g. HPLC and SPE), recognition component in bioassays (e.g. ELISA) or biomimetic recognition layer in chemical sensor systems. Examples such as MIP-based selective analysis of flavones/flavonoids in wine, the determination of mycotoxins in beverages and analysis of organic contaminants in environment samples will elucidate the perspectives of this technology and will be contrasted with the challenges of rational MIP design providing control on binding site density, receptor capacity and selectivity.

Recognition of ephedrine enantiomers by molecularly imprinted polymers designed using a computational approach

A new approach to the computational design of molecularly imprinted polymers (MIP) specific for ephedrine is presented. A virtual library of functional monomers was developed and screened against the template using molecular modelling software. The monomers giving the highest binding score were co-polymerized with a cross-linker in the presence of ephedrine. Control (blank) polymers were prepared under the same conditions but in the absence of the template. A good correlation was found between the modelling results and performance of the materials in an HPLC study. A MIP based on one of the selected monomers—hydroxyethyl methacrylate—gave a separation of ephedrine enantiomers with a separation factor α of 1.42–2.09 (depending on temperature). This figure is larger than the α values generally obtained with commercially available chiral phases. It is anticipated that the computational approach will be of use for the rational design of MIPs and the prediction of polymer affinity and specificity.

Thermodynamic Considerations for the Design of and Ligand Recognition by Molecularly Imprinted Polymers

Abstract Thermodynamic considerations relevant to molecularly imprinted polymer (MIP) preparation and non-covalent interaction based ligand recognition are presented. Together with the description of a semi-quantitative approach to recognition analysis, adapted for MIPs, thermodynamically based principles for MIP design are discussed.