Molecular Imprinted Nanoparticles for More Than Molecular Recognition – Synthesis and Processing
G.E.M. Tovar, K. Niedergall, T. Schreiber, D. Wojciukiewicz, T. Gose, J. Riegler, C. Gruber-Traub, A. Weber, T. Hirth
Fraunhofer IGB, DE
Keywords: molecular recognition, artificial receptor, specifically adsorbing material
Abstract:Molecular recognition plays a crucial role in nature and is fundamental for many applications in separation technology, analytics or sensor technology. Biologically derived receptors such as antibodies or enzymes are very specific molecular recognition units but chemically rather instable. Additionally, such biomacromolecules represent rather expensive polymeric materials. Molecular imprinting of polymeric material (MIP) is a highly attractive route to synthesize artificial receptors which combine the specificity of biological binding sites with the superior chemical stability of synthetic materials. Selective molecular binding sites are induced in a growing crosslinked polymeric material by template interaction of a nonpolymerising agent which interact noncovalently with specific parts in the polymer. The templates are washed from the generated polymer monoliths and the induced artificial binding sites can be applied for molecular recognition reactions. Nanostructured MIP monoliths (nanoMIP) can be prepared by a modified miniemulsion polymerisation technique, where the monomer, the template, the cross-linker, and the initiator are reacted in the droplet cavities of an emulsion. The reaction, although complex, runs in a single reaction chamber and in a single-step chemical process. Thus a variety of active agents ranging from low molecular weight drugs to peptides, proteins and biomacromolecules can be imprinted. NanoMIP dispose of the high surface area of nanostructrued material and are thus highly attractive for use as specifically absorbing material. Moreover, nanoMIP synthesis overcomes some crucial limitations of the preparation of imprinted material such as chemical inhomogeneity of a molecular imprinted polymeric matrix. The technique of miniemulsion polymerization results in particles with typical sizes between 50 and 300 nm. Besides classic miniemulsion polymerization (hydrophobic phase emulsified in hydrophilic phase – here water), a MIP technique also based on inverse miniemulsion polymerization is established. Thus, possible templates can be chosen from the full range of hydrophilic over amphiphilic to hydrophobic molecules. Additives like inorganic nanocrystals or organic fluorophores can be easily added to polymerization process. Thus nanostructrured hybrid-materials with multiple properties (fluorescence, magnetism) and specific binding sites are easily designed as valuable material in modern bio-analytics and diagnostics as well as in down stream processing in chemical and pharmaceutical industry. Widespread use in applications ranging from medical technology to environmental technology can be envisaged with the approach and will be discussed.