Research Progress of the Molecularly Imprinted Cryogel

Cryogel is an elastic, loose, and porous spongy hydrogel prepared via addition polymerization from monomers or cross-linking reaction of a polymer at a temperature lower than the freezing point of the solvent. Cryogel has mainly been used in the form of molecular imprinting cryogel based solid phase extraction in analytical chemistry, which combines the advantages of high selectivity of the molecularly imprinted technique with the porous structure, high throughput of a cryogel. Cryogel has a unique advantage of keeping the biological activities of proteins while used in separating and purifying proteins. Molecularly imprinted cryogel can act as the stationary phase in a packed column or a monolith column, as well as the adsorbent in a separation membrane. A variety of molecules, including small molecule, macromolecule, and certain fragment of macromolecule, can act as template molecules. Even inorganic ions can be used as template. Thus, both simple template and complex template can be used. When we employ more than a molecule (or an ion) as co-template simultaneously, the method is termed as mixed template. In addition, high abundance components themselves of a complex sample may act as a mixed template, which is named as the pending template. Further, while an analogue, an isotopic label, or a fragment of the target substance acts as a template, the method is defined as the dummy template.