Molecularly imprinted polymers (MIPs) in the micron and submicron
scale based on the bifunctional cross-linker N,O-bismethacryloylethanolamine (NOBE) have been
synthesized using bulk and miniemulsion polymerization, respectively.
MIPs with distinct selectivity for the template testosterone were
obtained. Colloidal MIP particles made using the miniemulsion technique
have significant advantages compared to bulk MIP counterparts owing
to their small size, homogeneity, and increased surface, as is demonstrated
by optical batch rebinding studies using a nonimprinted polymer (NIP)
as a negative control. Affinity and selectivity studies were also
performed with the miniemulsion colloidal MIPs. These MIPs display
largely increased imprint factors (6.8 vs 2.2) when compared to their
bulk MIP counterparts. Further, selectivity studies by using analogue
steroids show that colloidal MIPs also display a higher selectivity.
In summary, miniemulsion MIPs show much better performance with respect
to molecular recognition in aqueous solution, while providing at the
same time the possibility for a water-based MIP synthesis.