Application of porous microspheres prepared by SPG (Shirasu porous glass) emulsification as immobilizing carriers of glucoamylase (GluA)

Abstract

Fairly uniform spheres of crosslinked polystyrene (PS) and polymethyl methacrylate (PMMA), prepared by a particular emulsification process using SPG (Shirasu Porous Glass) membranes and subsequent suspension polymerization, were applied for immobilizing carriers of Glucoamylase (GluA). A mixture of monomers, solvents, and oil-soluble initiator was allowed to permeate through the micropores of SPG, suspended in an aqueous solution of poly(vinyl alcohol), and polymerized while retaining the narrow size distribution during polymerization. A small amount of acrylic acid or glycidyl methacrylate (GMA) was incorporated for the immobilization of GluA via covalent bonding. Although GluA has been regarded as being difficult to retain its activity after the immobilization process, a porous structure of the carriers definitely favored the immobilization, and a maximum 55% relative activity (RA) was obtained by the physical adsorption to PMMA spheres. The reaction of epoxide in GMA with 6aminocaproic acid provided a spacer arm for the carboxyl group. An improvement of activity was expected by the incorporation of the spacer arms; however, barely noticeable activity was observed for PMMA carriers either by the physical adsorption or by the covalent bonding. A slight improvement was observed for PS carriers with spacers compared to the carriers without them. The diffusion process of oligosaccharides in the porous carriers seemed to retard the rate of hydrolysis in the case of largest carriers, 60 mm PS-DVB-AA spheres. The activity of immobilized GluA was retained during a long storage period of more than 150 days, some of them even increasing gradually, while the activity of native GluA dropped to zero after 100 days.

Influence of process parameters on droplet size distribution in SPG membrane emulsification and stability of prepared emulsion droplets

“…These applications include the preparation of multiple emulsions for drug delivery systems (DDS), solder particles for surface mount technology [4], solid microcarriers for the encapsulation of a drug or nutrient using solid edible oil at an elevated temperature [6], silica powder for HPLC [7], monodispersed polymer microspheres, etc. The microspheres prepared by ME have been investigated as packings for analytical columns [8], carriers of enzymes [9], spacers for liquid crystal displays [7], and core particles for toner application [10].…”

Study on preparation of monodispersed poly(styrene-co-N-dimethylaminoethyl methacrylate) composite microspheres by SPG (Shirasu Porous Glass) emulsification technique

“…Monodispersed microspheres provide wide applications, for example, carriers of enzymes,1–4 cells,5 and DNAs 6. Particularly, monodispersed large microspheres with several to 100 μm with functional groups found high performance as the carriers of the above‐active substances in packing column or bioreactors, and of drugs in drug delivery system (DDS) 7–12.…”

Dependence of morphological changes of polymer particles on hydrophobic/hydrophilic additives

“…The need for polymeric microspheres of controlled size with a narrow size distribution has grown steadily because they are used in scientific and industrial applications such as chromatographic packing materials,1, 2 dry and liquid toner for electrophotography,3, 4 and support for medicines 5. For electrophotographic printing, the conventional dry toners consist of a colorant and additives, such as a charge control agent, dispersed on a polymeric material.…”

“…The uniform microspheres with sizes ranging from 1 up to 100 μm are normally obtained depending on the SPG pore size and monomer type 8, 9. Omi et al5, 10 extensively investigated the SPG technique for the syntheses of microspheres of crosslinked porous polystyrene10, 11 and poly(methyl methacrylate)12–14 controlled either by solubility parameters or a two‐stage emulsion technique. Hatate et al prepared poly(styrene‐ co ‐divinylbenzene) microspheres as dry toner particles containing a colorant and a charge‐control agent by using the SPG emulsification technique 3, 4.…”