3D printing of molecularly imprinted polymers for biomolecule removal

Molecularly imprinted polymers, or MIPs, are artificial receptors developed thanks to the molecular imprinting technology, which allows the formation of specific binding sites created in a polymeric matrix. Since the size, shape, and functional groups of these cavities complement a target molecule (template) with high selectivity and specificity, MIPs can be employed to mimic the molecular recognition capabilities of natural biological receptors. The advantages of MIPs over natural receptors include superior mechanical strength, resistance to harsh environmental conditions (like high temperatures and pressures), lower production costs, simplicity of synthesis, and remarkable template selection versatility. A wide range of industries, including drug delivery, biosensing, separation science, purification, analytical assays, catalysis, and artificial antibodies, have become increasingly interested in MIPs due to these features. Molecularly Imprinted Polymers (MIPs) can be classified into two main categories: hard and soft MIPs. Hard MIPs are characterized by high stability and high selectivity, although the removal of the template molecule is often complex due to the strong interactions involved. In contrast, soft MIPs exhibit moderate selectivity and lower stability, as they rely on reversible interactions, which also allow for easier template removal. The mechanical properties are determined by the characteristics of the monomers and the crosslinkers selected to create the polymeric network, together with an initiator that is needed to start the polymerization process. The last element necessary for the MIPs fabrication is obviously the template, i.e. the target molecule to be recognized. In this context, in this Thesis two molecules were tested as template molecules: oxytetracycline (OTC), an antibiotic with pharmaceutical and environmental significance, and bovine serum albumin (BSA), a frequently used model protein. Following previous studies, in this thesis Hard MIPs that used OTC as a template were fabricated employing Digital Light Processing (DLP), a high-resolution 3D printing method that makes possible to fabricate intricate, self-supporting polymeric structures. Then the efficacy of the MIPs was investigated to be able to capture the target molecule in a controlled environment, analyzing it using the UV-Vis. OTC-MIP produced in this way could be seen as an alternative to treat antibiotic-contaminated water and could lead to the development of a more efficient and sustainable water purification system. In parallel, preliminary studies were carried out on Soft MIPs where BSA was selected as template molecule. In this case a resin containing BSA was formulated and polymerized. This material was then characterized using UV-Vis spectroscopy, investigating MIP capability and the effect of the various ingredients on protein stability. Summarizing, this study aims at studying hard and soft MIPs, trying to establish bottlenecks and capabilities of next generation artificial receptors.