Boc-l-tryptophan imprinted polymeric microparticles for bioanalytical applications

Molecularly imprinted polymer (MIP) microparticles with good chromatographic characteristics were synthesized via the suspension polymerization process in a single preparative step. Initially, the effects of process parameters (i.e., porogen concentration, polymerization temperature, types and concentrations of functional monomer and cross-linker) on the particle size distribution and particle morphology were experimentally investigated. Subsequently, various MIP microparticles were synthesized in the presence of an amino acid derivative (i.e., boc-l-tryptophan), acting as template molecule. Batch-wise guest binding experiments were then performed to determine the rebinding capacity of the synthesized MIP microparticles towards the template molecule. Competitive binding experiments were also carried out with boc-d-tryptophan (i.e., the enantiomer of boc-l-tryptophan) to assess the selectivity of the imprinted polymer microparticles towards the two enantiomers. Finally, a quantitative description of the experimentally measured rebinding isotherms was obtained using the well-known Freundlich–Langmuir models. The present results clearly demonstrate the potential application of the synthesized MIP microparticles for bioanalytical separation of peptides and proteins since the amino acid templates employed in this study are the building units of larger biomolecules.