Binding site characteristics of 17beta-estradiol imprinted polymers

Area of Science:

• Polymer Chemistry
• Analytical Chemistry
• Materials Science

Background:

• Molecularly imprinted polymers (MIPs) are versatile materials with applications requiring diverse formats like films, particles, or spheres.
• Micro- and sub-microspheres are advantageous MIP formats due to monodispersity and facile synthesis compared to bulk polymerization.
• Detailed studies on rebinding characteristics across different MIP formats under various conditions are lacking.

Purpose of the Study:

• To develop a generic analytical strategy for MIP rebinding studies, including equilibrium, non-equilibrium, and release experiments.
• To compare the rebinding characteristics of three MIP formats (irregular particles, microspheres, sub-microspheres) for 17beta-estradiol.
• To understand the molecular interactions between MIPs and template molecules based on material properties.

Main Methods:

• Synthesized three MIP formats: bulk polymers, microspheres, and sub-microspheres for 17beta-estradiol using precipitation polymerization.
• Characterized MIP morphology using scanning electron microscopy (SEM).
• Analyzed MIP porosity using Brunauer-Emmett-Teller (BET) analysis and performed equilibrium and non-equilibrium binding studies.

Main Results:

• Microspheres prepared via precipitation polymerization exhibited superior equilibrium rebinding properties compared to bulk polymers and sub-microspheres.
• Non-equilibrium rebinding yielded a higher median binding affinity constant and a more homogeneous binding site distribution (heterogeneity index m=0.725) than equilibrium rebinding.
• Reduced surface area due to lower cross-linker-to-template ratios correlated with fewer specific binding sites. Optimal pore size (100-180 Å) is critical for HPLC applications.

Conclusions:

• MIP microspheres demonstrate enhanced rebinding performance, making them suitable for analytical applications.
• Non-equilibrium binding studies provide deeper insights into MIP binding site homogeneity and affinity.
• Controlling MIP porosity and surface area is essential for tailoring binding capacity and achieving desired performance in analytical separations.