Polyglycidyl methacrylate based immunoaffinity cryogels for insulin adsorption

Molecularly Imprinted Cryogels for the Selective Adsorption of Salicylic Acid

In this study, molecularly imprinted cryogels were fabricated for selective adsorption of salicylic acid. Cryogelation was performed at - 20 °C using a cationic monomer N,N-dimethylaminoethyl methacrylate as a functional monomer for salicylic acid. The morphology, swelling behaviors, and chemical structures of the cryogels were investigated. The general structure and porosities of cryogels were compared with the traditional hydrogels using field emission scanning electron microscopy (FE-SEM). The adsorption performance of cryogels toward salicylic acid was studied to investigate the optimal adsorption conditions. Adsorption capacity of the imprinted cryogels was 1.95 and 7.51 times higher than those of non-imprinted and bare PHEMA cryogels, respectively, due to the specific binding sites toward salicylic acid. Molecularly imprinted cryogels exhibited significant stability and reusability by keeping more than 85% of their adsorption capacity after ten regeneration cycles. Considering the fabrication process, adsorption capacity, selectivity, and reusability of the imprinted cryogels, these new materials could be utilized as a promising alternative for selective adsorption of drug molecules.

A comprehensive review of cryogels and their roles in tissue engineering applications

The extracellular matrix is fundamental in providing an appropriate environment for cell interaction and signaling to occur. Replicating such a matrix is advantageous in the support of tissue ingrowth and regeneration through the field of tissue engineering. While scaffolds can be fabricated in many ways, cryogels have recently become a popular approach due to their macroporous structure and durability. Produced through the crosslinking of gel precursors followed by a subsequent controlled freeze/thaw cycle, the resulting cryogel provides a unique, sponge-like structure. Therefore, cryogels have proven advantageous for many tissue engineering applications including roles in bioreactor systems, cell separation, and scaffolding. Specifically, the matrix has been demonstrated to encourage the production of various molecules, such as antibodies, and has also been used for cryopreservation. Cryogels can pose as a bioreactor for the expansion of cell lines, as well as a vehicle for cell separation. Lastly, this matrix has shown excellent potential as a tissue engineered scaffold, encouraging regrowth at numerous damaged tissue sites in vivo. This review will briefly discuss the fabrication of cryogels, with an emphasis placed on their application in various facets of tissue engineering to provide an overview of this unique scaffold's past and future roles.

STATEMENT OF SIGNIFICANCE

Cryogels are unique scaffolds produced through the controlled freezing and thawing of a polymer solution. There is an ever-growing body of literature that demonstrates their applicability in the realm of tissue engineering as extracellular matrix analogue scaffolds; with extensive information having been provided regarding the fabrication, porosity, and mechanical integrity of the scaffolds. Additionally, cryogels have been reviewed with respect to their role in bioseparation and as cellular incubators. This all-inclusive view of the roles that cryogels can play is critical to advancing the technology and expanding its niche within biomaterials and tissue engineering research. To the best of the authors' knowledge, this is the first comprehensive review of cryogel applications in tissue engineering that includes specific looks at their growing roles as extracellular matrix analogues, incubators, and in bioseparation processes.

P(TA) macro-, micro-, nanoparticle-embedded super porous p(HEMA) cryogels as wound dressing material

Super porous poly(2-hydroxy ethyl methacrylate) (p(HEMA)) cryogel was successfully synthesized by using polyethylene glycol diacrylate (p(EGDA)) crosslinker under cryogenic conditions. Poly(Tannic acid) (p(TA)) macro-, micro-, and nanoparticles prepared from a natural polyphenol, tannic acid (TA), were embedded into p(HEMA) cryogel networks to obtain composite p(TA) particle-embedded p(HEMA) cryogel. Different size ranges of spherical p(TA) particles, 2000-500μm, 500-200μm, 200-20μm, and 20-0.5μm size, were included in the cryogel network and illustrated by digital camera, optic microscope, and SEM images of the microgel-cryogel network. The swelling properties and moisture content of p(TA) microgel-embedded p(HEMA) cryogel were investigated at wound healing pH conditions such as pH5.4, 7.4, and 9 at 37.5°C, and the highest swelling capacity was found at pH9 with 972±2% swelling in 30s. Higher amounts of DI water were quickly absorbed by p(HEMA)-based cryogel, and moisture retention within the cryogel structure for a longer time period at room temperature is due to existence of p(TA) particles. Degradation profiles of p(TA) particle-embedded p(HEMA) cryogel were shown to be controlled by different pH conditions, and a linear release profile was found with total cumulative release of 5.8±0.8mg/g TA up to 12days at pH7.4 and 37.5°C. The antioxidant behavior of degraded p(TA) particles from p(HEMA) cryogel were found as 46±1μgmL^-1 gallic acid equivalent and 165±18mMtroloxequivalentg^-1. The p(TA) particle-embedded p(HEMA) cryogel has high hemocompatibility with 0.0158±0.0126% hemolysis ratio, and effective hemostatic properties with 8.1±0.9 blood clotting index.