ABSTRACT
Cryogels are a type of hydrogel material which are fabricated by cryopolymerization at subzero temperature. Due to their unique macroporous structure, shape memory properties and injectability, cryogels have gained significant interest in the fields of tissue engineering for encouraging the repair and regeneration of injured tissues. In this review, the basic concepts relevant to cryogels are introduced, and then the fabrication principle, the process parameters and the unique properties of cryogel are discussed. Next, the latest advances of cryogels as three-dimensional scaffold for various tissue engineering applications are given. Finally, this review summarizes the current limitations of cryogels, and strategies to further improve their properties for tissue engineering. The purpose of this article is to provide a reference guide for the researchers in related fields.
Subject(s)
Cryogels , Porosity , Tissue Engineering , Tissue ScaffoldsABSTRACT
Lysozyme, pepsin, ovalbumin, hemoglobin andγ-globumin were chosen as templates to investigate the imprinting capability of amphoteric polyacrylamide cryogels. Prepolymerizing solutions contained acrylic acid and allyl amine, as well as acrylamide and N,N'-methylenebisacrylamide as the functional monomers. As a result there were both acidic and basic functional groups in the polymers, facilitating effective interactions with likewise amphoteric proteins. The proteins differ greatly and cover wide scopes of molecular weights and isoelectric points. Regardless of the values of the molecular weights and isoelectric points, all the templates gave higher retentions on the MIP tubes than on the NIP tube. The MIP of lysozyme indicated the highest imprinting factor of 7. 0, and that of γ-globumin showed the lowest, 2. 0. The values of other proteins were intervenient. Conclusively the amphoteric polyacrylamide cryogels were suitable imprinting materials for various proteins, and could potentially be used for protein recognition, purification, and depletion.
ABSTRACT
Cryogel is a kind of elastic, spongy hydrogel prepared via addition polymerization from monomers or cross-linking reaction from a polymer at a temperature lower than the freezing point of the solvent. Cryogel has been principally used in molecular imprinting cryogel based solid phase extraction in the field of analytical chemistry, which combines both the advantages of high selectivity of the molecular imprinting and the porous structure, high throughput of a cryogel. Molecular imprinting cryogel can be used as the stationary phase in a packed column, a monolith column, or the adsorbent in a separation membrane. A variety of molecules can act as template molecules, including small molecules, macromolecules, a certain fragment of a macromolecule, and even an inorganic ion. Both a simple template and a complex template can be used. When employing more than a molecule ( or an ion) as templates simultaneously, the method is termed as Mixed template. While high abundance components of a complex sample act directly as mixed template, we name the method as 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 Dummy template. However, the research on cryogel is insufficient and the application of the cryogel is narrow hitherto.