Preparation of polyelectrolyte‐coated pH‐sensitive poly(styrene) microcapsules and their application to initiation‐cessation control of an enzyme reaction

Abstract

Poly(styrene) microcapsules, prepared by depositing the polymer around emulsified aqueous droplets, were coated with a synthesized polyelectrolyte; i.e., copolymer of maleic acid (MA) with methyl vinyl ether (MVE), co-poly(MA, MVE), or with styrene (St), copoly(Ma, St). The permeability of the capsule membrane was investigated under various pHs of the outer medium using n-propyl alcohol as a permeant. It became apparent that either copoly(MA, St)- or copoly(MA, MVE)-coated microcapsules function as a pH-sensitive capsule. In particular, the former showed a dramatic change of the permeability in response to small differences in pH (5-6). By reference to the viscometric and electrophoretic studies of both copolymers, these were interpreted as being due to a pH-induced alteration of the configuration of the copolymer coating on the surface of the capsule membrane. When sucrose was hydrolyzed in an aqueous suspension of the copoly(MA, St)-coated capsules into which invertase was loaded, the hydrolytic reaction was initiated at pH 5. 5 and stopped at pH 4. 5. Such initiation-cessation control was repeated reversibly without damaging the capsules.

Environmentally Responsive Core/Shell Particles via Electrohydrodynamic Co‐Jetting of Fully Miscible Polymer Solutions

“…Under these conditions the polyelectrolyte chains exhibit a more stretched form, and inter‐ and intramolecular repulsion causes increased absorption of water and expansion of the particles. When exposed to an acidic media, the carboxylic‐acid groups are protonated, eliminating charge‐charge repulsion and cause shrinkage of the particles 39, 40. In Figure 3, histograms are shown for each condition indicating the number of particles that fall within one of four size ranges; smallest (<25%); small/medium (26–50%); medium/large (51–75%); and largest particle fraction (>75%).…”

“…When exposed to an acidic media, the carboxylicacid groups are protonated, eliminating charge-charge repulsion and cause shrinkage of the particles. [39,40] In Figure 3, histograms are shown for each condition indicating the number of particles that fall within one of four size ranges; smallest (<25%); small/medium (26-50%); medium/large (51-75%); and largest particle fraction (>75%). When exposed to a sufficiently high pH, the acid groups are deprotonated and repulsion between negatively charged polymer chains causes expansion of the particles.…”

Virus capture using anionic polymer-coated magnetic beads (Review)

“…The extremely polar polymeric free acid is highly negatively charged in water and can be used for endowing an anionic charge after the grafting of the anionic polymer to magnetic beads. They also have large numbers of reactive groups (38) and are able to efficiently capture biomolecules including glycine (37), phosphatidylcholine (37), oligonucleotides (39), enzymes (40) and calcium (41). Although the mechanism by which poly(MVE-MA)-coated magnetic beads bind to viruses remains unclear, components on the viral surface such as proteins, lipids and sugar chains may contribute to the binding process.…”

Permeability characteristic of polyelectrolyte complex capsule membranes: Effect of preparation condition on permeability

“…( 2 ) obtained from Fick's first law of diffusion: ( 2 ) where t represents the time since the start of the experiment. C', C t , and C' are the initial, intermediary, and final concentrations in volume V of the surrounding phase, respectively.…”