Molecularly imprinted polymer
The process usually involves initiating the polymerization of monomers in the presence of a template molecule that is extracted afterwards, leaving behind complementary cavities.
Molecular imprinting is the process of generating an impression within a solid or a gel, the size, shape and charge distribution of which corresponds to a template molecule (typically present during polymerisation).
Furthermore, when necessary, the activity in response towards outer stimuli (photo-irradiation, pH change, electric or magnetic field, and others) can be provided by using appropriate functional groups.
The self-assembly method has advantages in the fact that it forms a more natural binding site, and also offers additional flexibility in the types of monomers that can be polymerized.
The covalent method has its advantages in generally offering a high yield of homogeneous binding sites, but first requires the synthesis of a derivatized imprint molecule and may not imitate the "natural" conditions that could be present elsewhere.
Consequently, significant progress has been made in developing polymerization methods that produce adequate MIP formats with rather good binding properties expecting an enhancement in the performance or in order to suit the desirable final application, such as beads, films or nanoparticles.
The resultant polymeric block is then pulverized, freed from the template, crushed and sieved to obtain particles of irregular shape and size between 20 and 50 μm.
[9][10][11] An adaptation of the solid-phase protocol was performed by Sullivan et al. who used a modified aptamer as a recognition macromonomer, encapsulated within a polymer nanoparticle scaffold.
[12] [13] Molecular modelling has become a convenient choice in MIP design and analysis, allowing rapid selection of monomers and optimization of polymer composition, with a range of different techniques being applied.
[16][17][18] In recent years technological advances have permitted more efficient analysis of monomer-template interactions by quantum mechanical molecular modelling, providing more precise calculations of binding energies.
Fast and cost-effective molecularly imprinted polymer technique has applications in many fields of chemistry, biology and engineering, particularly as an affinity material for sensors,[28] detection of chemical, antimicrobial, and dye, residues in food, adsorbents for solid phase extraction, binding assays, artificial antibodies, chromatographic stationary phase, catalysis, drug development and screening, and byproduct removal in chemical reaction.
[29] Molecular imprinted polymers pose this wide range of capabilities in extraction through highly specific micro-cavity binding sites.
[30][31] Due to the specific binding site created in a MIP this technique is showing promise in analytical chemistry as a useful method for solid phase extraction.
[32] The capability for MIPs to be a cheaper easier production of antibody/enzyme like binding sites doubles the use of this technique as a valuable breakthrough in medical research and application.
When H2SO4 was used as the polymerization initiator (acidifying agent), a positive correlation was found between surface areas, e.g. load capacities, and the molecular weights of the respective solvents.
Shortly after this work appeared, molecular imprinting attracted wide interest from the scientific community as reflected in the 4000 original papers published in the field during for the period 1931–2009 (from Scifinder).
The first, and lesser, challenge arises from choosing those monomers which will yield adequate binding sites complementary to the functional groups of the substrate molecule.
Most of the developments in MIP production during the last decade have come in the form of new polymerization techniques in an attempt to control the arrangement of monomers and therefore the polymers structure.
