Can binding sites be produced in organic or inorganic polymers—similar to those in antibodies—which are able to recognize molecules and which may have catalytic action? In this article we review a method, analogous to a mechanism of antibody formation proposed earlier, by which in the presence of interacting monomers a cross-linked polymer is formed around a molecule that acts as a template. After removal of the template, an imprint containing functional groups capable of chemical interaction remains in the polymer. The shape of the imprint and the arrangement of the functional groups are complementary to the structure of the template. If chiral templates are used, the success of the imprinting process can be assessed by the ability of the polymer to resolve the racemate of the template molecule. Through optimization of the process has led to chromatographic separation factors of α = 4–8, and to base line separations. There is also great interest in the surface imprinting of solid materials and monolayers. In all cases, the structure of the polymeric matrix in the imprinted materials and the function of the binding groups are of crucial importance. The mechanisms of imprinting and molecular recognition of substrates are by now well understood. A large number of potential applications for this class materials are being intensively developed, for example in the chromatogrphic resolution of recemates, and as artificial antibodies, chemosensors, and selective catalysts. The use of similarly produced materials as enzyme models is also of great interest. 相似文献
A non-covalent type of molecular imprinting effect toward a polyaromatic hydrocarbon (PAH), viz. anthracene, was studied utilizing uniformly sized ethylene dimethacrylate (EDMA) polymer particles without functional host monomers. Although polymerization at 0°C initiated by a redox initiation system was expected to afford larger molecular imprinting effect due to stronger and more effective intermolecular interaction between the template and surface functional groups of the polymer, almost no imprinting effect was observed, while a much higher polymerization temperature of 70°C unexpectedly afforded a larger molecular imprinting effect for the template anthracene. In order to determine the unexpected imprinting effects observed, uniformly sized, macroporous un-imprinting EDMA polymer particles (base particles) were prepared by various polymerization techniques at different polymerization temperature as well as with different initiation systems. The careful studies proved that each kind of base polymer particle showed different molecular recognition ability, especially toward anthracene, which is depends upon the physical properties of each kind of base polymer particle. On the basis of these facts, we would propose that the potential molecular recognition ability of the un-imprinted base polymer particles is another important factor for realization of effective molecular imprinting alongside the factors reported previously. 相似文献
Polymeric sorbents targeting endocrine‐disrupting estrogen active compounds (EAC) were prepared by terpolymer imprinting using 17β‐estradiol (E2) as template. From a group of eight functional monomers representing Brønsted acids, bases, hydrogen‐bond donors and acceptors, as well as π‐interacting monomers, a terpolymer library that comprises all possible binary combinations of the functional monomers was prepared. Binding tests revealed that imprinted polymers exhibit a markedly higher affinity for E2 compared to nonimprinted polymers (NIPs) or polymers prepared by using single functional monomers. A combination of methacrylic acid (MAA) and p‐vinylbenzoic acid offered a particularly promising lead polymer, displaying an imprinting factor of 17 versus 2.4 for a benchmark polymer prepared by using only MAA as functional monomer. The saturation capacities ascribed to imprinted sites were four to five times higher for this polymer compared to previously reported imprinted polymers. NMR titrations and molecular dynamics simulations corroborated these results, indicating an orthogonal preference of the two functional monomers with respect to the E2 3‐OH and 17‐OH groups. The optimized polymer exhibited a retentivity for EACs that correlates with their inhibitory effect on the natural receptor. By using the optimized molecularly imprinted polymers (MIPs) in a model water‐purification system, they were capable of completely removing ppb levels of a small group of EACs from water. This is in contrast to the performance of nonimprinted polymers and well‐established sorbents for water purification (e.g., active carbon), which still contained detectable amounts of the compounds after treatment. 相似文献
Exosomes are small (30–100 nm) membrane vesicles that serve as regulatory agents for intercellular communication in cancers. Currently, exosomes are detected by immuno‐based assays with appropriate pretreatments like ultracentrifugation and are time consuming (>12 h). We present a novel pretreatment‐free fluorescence‐based sensing platform for intact exosomes, wherein exchangeable antibodies and fluorescent reporter molecules were aligned inside exosome‐binding cavities. Such antibody‐containing fluorescent reporter‐grafted nanocavities were prepared on a substrate by well‐designed molecular imprinting and post‐imprinting modifications to introduce antibodies and fluorescent reporter molecules only inside the binding nanocavities, enabling sufficiently high sensitivity to detect intact exosomes without pretreatment. The effectiveness of the system was demonstrated by using it to discriminate between normal exosomes and those originating from prostate cancer and analyze exosomes in tear drops. 相似文献
Exosomes are small (30–100 nm) membrane vesicles that serve as regulatory agents for intercellular communication in cancers. Currently, exosomes are detected by immuno‐based assays with appropriate pretreatments like ultracentrifugation and are time consuming (>12 h). We present a novel pretreatment‐free fluorescence‐based sensing platform for intact exosomes, wherein exchangeable antibodies and fluorescent reporter molecules were aligned inside exosome‐binding cavities. Such antibody‐containing fluorescent reporter‐grafted nanocavities were prepared on a substrate by well‐designed molecular imprinting and post‐imprinting modifications to introduce antibodies and fluorescent reporter molecules only inside the binding nanocavities, enabling sufficiently high sensitivity to detect intact exosomes without pretreatment. The effectiveness of the system was demonstrated by using it to discriminate between normal exosomes and those originating from prostate cancer and analyze exosomes in tear drops. 相似文献
The interaction process between the phenobarbital(PHN) and acrylamide(AM) was studied using the M062X/6-31G(d,p) method. The PHN and AM were used as the template and functional monomer,respectively. The molecular electrostatic potential(MEP) was simulated for predicting the reactive sites. The atoms in molecules theory helped to reveal the imprinting mechanism and optimize the molar ratios for PHN and AM. The molecular imprinted polymers(MIPs) containing PHN were synthesized through the precipitation polymerization. The diameter range of the obtained MIPs was from 150 to 390 nm. According to the computational results,MIPs with the molar ratio of PHN and AM equal to 1:6 showed high selective adsorption for PHN. The apparent maximum adsorption quantity(Q_(max)) of MIPs toward PHN was 7.9 mg/g,and the Qmax of nonimprinted polymer microspheres(NIPs) was 3.2 mg/g. Herein,the studies can provide theoretical and experimental references for the controllable fabrication of MIPs. 相似文献
The tendency of bacteria to assemble at oil–water interfaces can be utilized to create microbial recognition sites on the surface of polymer beads. In this work, two different groups of bacteria were first treated with acryloyl‐functionalized chitosan and then used to stabilize an oil‐in‐water emulsion composed of cross‐linking monomers that were dispersed in aqueous buffer. Polymerization of the oil phase followed by removal of the bacterial template resulted in well‐defined polymer beads bearing bacterial imprints. Chemical passivation of chitosan and cell displacement assays indicate that the bacterial recognition on the polymer beads was dependent on the nature of the pre‐polymer and the target bacteria. The functional materials for microbial recognition show great potential for constructing cell–cell communication networks, biosensors, and new platforms for testing antibiotic drugs. 相似文献
This paper describes a new type of surface imprinting technique that combines the advantages of both the semi‐covalent approach and one‐stage miniemulsion polymerization. This process has been successfully applied for the preparation of glucose surface‐imprinted nanoparticles. The selective artificial receptors for glucopyranoside were fully characterized by IR, TEM and BET analyses, and their molecular recognition abilities by binding experiments carried out in batch processes. The molecular affinity and selectivity of the glucose molecularly imprinted polymers were accurately quantified. These characteristics are essential for verification of the efficiency of the developed surface imprinting process. The imprinting effect was clearly demonstrated using the batch rebinding method. We have found that the glucose imprinted polymers produced using the optimized one‐stage mini‐emulsion exhibited quite fast kinetics of binding and equilibration with glucopyranoside templates, compared to polymers prepared by bulk polymerization technique, as well as extremely low levels of unspecific bindings. We also demonstrated that glucose molecular imprinted polymer (MIP) exhibited very good selectivity for its original template compared to other glycopyranoside derivatives, such as galactose. Finally, the extraction of the binding properties from isotherms of binding by fitting to the bi‐Langmuir and Freundlich models allowed the determination of the affinity constant distribution of the binding sites. This imprinting protocol allowed the determination of an affinity constant (KD), involving exclusively H‐bonding interactions, for the glucose MIP ( P2C ) with the best template 1 , in CH3CN as the solvent system.
