The effect of crosslinking density on molecularly imprinted polymer morphology and recognition

[Display omitted] •Degree of crosslinking impacts on polymer morphology.•Correlations observed between morphology and polymer-template recognition.•Decreasing crosslinking density reduces template rebinding capacity. In this report, the crosslinking density of bupivacaine molecularly imprinted methacrylic acid (MAA)–ethylene glycol dimethacrylate (EGDMA) copolymers was investigated through replacement of EGDMA by methyl methacrylate (MMA). The effects were examined using a series of full-scale MD simulations of pre-polymerization mixtures, equilibrium rebinding studies on the corresponding synthesized polymers and morphology characterization through nitrogen sorption measurements. While the extent of hydrogen bonding between the functional monomer MAA and bupivacaine observed in the MD pre-polymerization mixtures was comparable in each of the systems studied, the decrease in degree of crosslinking impacted directly on polymer morphology as observed in BET and BJH studies of surface area and porosity. Further, decreases in the crosslinking density induced reductions in template rebinding capacity as seen from a series of radio-ligand binding studies, demonstrating the importance of crosslinking on the performance of molecularly imprinted MAA–EGDMA copolymers, the polymer system most commonly used in molecular imprinting science and technology.