Biomedical Engineering Reference
In-Depth Information
terms of strength, specificity, and directionality, the metal coordination interaction is more
like a covalent interaction than hydrogen bonding or electrostatic interactions in water. These
features make metal coordination a promising binding for the preparation of highly specific
templated polymers for the recognition of proteins, via the arrangements of metal
coordinating ligands on their surface.
Figure 3. Schematic representation of protein imprinting using immobilized templates.
Because of the effects of the temperature, pH, and the ionic concentration on the status of
biomacromolecules and the difficulty of the removal and rebinding of template molecules,
covalent immobilization of template proteins has not been widely considered in molecular
imprinting. However, there are several successful applications of covalent bond in molecular
imprinting. The immobilization of the protein template on a supporting substrate provides a
number of advantages, including the imprinting of templates independently of their solubility
in the polymerization system, minimizing protein aggregation and creating more
homogeneous binding sites. Using silanes based on template covalent immobilization, Shiomi
et al. [48] first produced surface-imprinted microspheres for hemoglobin. Covalent
immobilization was achieved by forming imine bonds between amino groups on the protein
surface and anchored aldehyde groups on silica, these bonds being readily broken by oxalic
acid [49] (Figure 3). The recognition appeared to not only depend on the molecular weight
and the electric charge, but also on shape and hydrophobicity of the pores created on silica.
Bonini et al. [50] modified the approach to fabricate silica-based imprinted beads for hunan
serum albumin using polyaminophenylboronic acid instead of silanes. The prepared
molecular imprinted polymer beads show recognition mainly due to shape interactions. Using
a two-stage core-shell miniemulsion polymerization inspired by the above work of Bonini et
al., Chau Jin Tan et al. [51] prepared bovine serum albumin imprinted particles with the
immobilization of the template protein molecules on polymeric (instead of silica) support
beads. In the competitive adsorption environment, it can be seen that the molecular imprinted
polymer prepared using this strategy can display highly specific recognition of bovine serum
albumin with no adsorption of the non-template proteins. Devanathan et al. reported [52], for
the first time, the formation of a biomimetic covalently imprinted polymeric sensor for a
