Unlike other affinity reagent technologies, MIPs are each developed around the target molecule as a physical template. Antibodies, and other affinity proteins, are based on a fixed architecture or scaffold which is then dressed with variable sequences often of a fixed length. Whilst there can be significant variation in the exact composition of the variable regions the overall structure, its size and shape are very similar: one IgG looks much like another with a relatively fixed portion involved in binding to the epitope. MIPs are very different. The overall architecture is formed around the target of interest, furthermore this is achieved only after individual interactions between MIP monomers and the corresponding features on the target molecule have been established. Only when these interactions have been allowed to occur are the monomers locked in position by the polymerisation event. It is this cross linking event which creates the target defined scaffold generating the optimal matrix to maintain the intermolecular bonds which constitute the binding of the MIP to the target.
The ability to generate large or small binding surfaces endows MIP technology with the flexibility to address a wide range of targets from small ions to macromolecular structures such as protein complexes. This diversity ensures the best binding surface for the target: the best tool for the job. Would you try picking up a tea cup with a fork lift? Or a shipping crate with a pair of surgical tweezers?
Vast arrays of possible monomers and cross linking agents are available from which to form MIPs, several such monomers being specifically developed by MIP Diagnostics and our founders. Recent reviews have counted over 5000 suitable monomers in the literature. This diversity gives us a much wider repertoire of interactions to allow us to select the best ones for any given target. The chemical space available is enormous compared to the 22 amino acids for protein affinity probes, or typically just four bases available or oligonucleotide affinity reagents.
Similarly whilst antibodies and other protein based reagents have a fixed scaffold, which determines the overall size and shape of their binding surface, MIPs are formed around the target itself which better provides for an optimal complementarity between the target and the MIP. This also applies to the orientation as well as the 3-dimensional positioning of the interacting chemical group.
The result is that MIPs can have extremely high affinity interactions with their target and are highly selective.
MIPs can be enhanced by building in certain functionality. MIP Diagnostics have the ability to incorporate a desired fluorophore into the body of the MIP itself ensuring a consistent and built in tag which is often brighter than the equivalent fluorophore conjugated to an antibody or other affinity probe. We can even make MIPs magnetic to facilitate purification, enrichment etc.