Biomedical Engineering Reference
In-Depth Information
a
c
assembly
(binding)
b
1. Add cross-linker
2. Polymerization
(in porogenic solvent)
template
removal
re-binding
recognition site
Figure 11.2
Schematic representation of synthesis of molecularly imprinted polymer.
porogenic solvent (polar or non-polar medium for polymerization) and
6) extraction solvent (to extract the template from cross-linked polymer
matrix) (Figure 11.2). h ere are two main methods for creating these spe-
cialized polymers. h e i rst is known as self-assembly, which involves the
formation of polymer by combining all elements of the MIP and allowing
the molecular interactions to form the cross-linked polymer with the tem-
plate molecule bound. h e second method of formation of MIPs involves
covalently linking the imprint molecule to the monomer. At er polym-
erization, the monomer is cleaved from the template molecule [3]. h e
selectivity is greatly inl uenced by the kind and amount of cross-linking
agent used in the synthesis of the imprinted polymer. h e selectivity is also
determined by the covalent and non-covalent interactions between the tar-
get molecule and monomer functional groups. h e careful choice of func-
tional monomer is another important choice to provide complementary
interactions with the template and substrates [4].
In an imprinted polymer, the cross-linker fuli lls three major func-
tions: First of all, the cross-linker is important in controlling the mor-
phology of the polymer matrix, whether it is gel-type, macroporous or
a microgel powder. Secondly, it serves to stabilize the imprinted bind-
ing site. Finally, it imparts mechanical stability to the polymer matrix.
From a polymerization point of view, high cross-link ratios are gener-
ally preferred in order to access permanently porous materials and in
