Preparation and characterization of supermacroporous polyacrylamide cryogel beads for biotechnological application

Abstract

Polymer beads, particularly supermacroporous beads, play important roles in biotechnological applications, such as their application as adsorbents in bioseparation processes and used as carriers in immobilization of cells or/and enzymes. In this study, supermacroporous polyacrylamide (pAAm) based cryogel beads were prepared via an inverse suspension polymerization method at low temperature (<0 C). Standard porous beads were also prepared at room temperature for comparison. The results showed that the diameter of the beads were in the range of 50-400 lm and some irregular large pores of the beads were of 3-90 lm in diameter, which had good biocompatibility, hydrophilicity, high porosity and large connected pores. To modify the properties of these cryogel beads, cryogel beads embedded with nanoparticles of TiO 2 were also prepared. The physical properties of the composite cryogel beads with supermacroporous were characterized and the results showed an improvement in mechanical strength and stability, which indicated that these supermacroporous cryogel beads may be useful in biotechnological applications as the networks in the beads can facilitate the mass transfer of nutrients and oxygen.

Tuning the Range of Polyacrylamide Gel Stiffness for Mechanobiology Applications

“…The samples were then gradually dehydrated using a series of ethanol dehydration steps (50, 70, 90, 100% ethanol) and dried at their critical point with liquid CO 2 using the Tousimis Autosamdri Critical Point Dryer (815B, Rockville, MD) with 20 min of purge time. CPD has been used for SEM preparation of polyacrylamide hydrogels 42 to avoid the damaging effects of air−liquid interfaces. The samples were dried with CPD for 1 h to achieve gradual exchange of 100% ethanol to liquid CO 2 , followed by an increase in temperature to 31 °C and pressure to 1350 psi (the critical point of CO 2 ), and gradual bleeding of the resultant CO 2 gas.…”

Micro Sponge Balls: Preparation and Characterization of Sponge-like Cryogel Particles of Poly(2-hydroxyethyl methacrylate) via the Inverse Leidenfrost Effect

“…Polymer particles are often processed by coating their surface, mixing different monomers to prepare composite materials, and/or enclosing the beneficial materials (i.e., catalysts and bioagents) inside, depending on the intended applications. In general, polymer particles can be prepared by several methods including: (i) inverse emulsion polymerization, − (ii) Pickering emulsion polymerization, , (iii) solvent evaporation polymerization, , and (iv) mechanical stirring in a multi-phase system . A common feature of the above methods is the requirement of a surfactant/detergent substance to stabilize the multi-phase interface, where the preparation conditions must be optimized for each polymer material; however, to maintain both the stability of the dispersed phase and a good reactivity at the interface, the applied surfactant/detergent must remain in the obtained polymer particles.…”