A novel type of polyethersulfone porous microcapsule membranes with straight pores across the whole thickness was successfully prepared with a gel-sol phase inversion method for the immobilization of microbial cells. The mean diameter of the microcapsules was about 2mm, and the microcapsule membranes were full of straight finger pores. The pore size distribution was from 3.5 to 53.6m and the median pore diameter was 13.6m. The prepared microcapsules had large total pore volume, and total pore area and porosity (as large as 91.7%). The prepared porous microcapsules were used as carriers for the immobilization of microbial cells in the anaerobic wastewater biotreatment process. Immobilized anaerobic microbial cells were found both inside the membrane pores and in the inner spaces of microcapsules. The prepared porous microcapsules were proven to be efficient for the microbial immobilization under anaerobic conditions.

Wehave successfully prepared monodispersed thermoresponsive core-shell microcapsules with a mean diameter of about 4μm with a porous membrane and with linear-grafted poly (N-isopropylacrylamide) (PNIPAM) chains in the membrane pores acting as thermoresponsive gates. The preparation was carried out by using a Shirasu porous glass (SPG) membrane emulsification technique to prepare small-sized monodispersed oil-in-water emulsions and using interfacial polymerization to prepare the core-shell microcapsules with porous membranes. Plasma-graft pore-filling polymerization was used to graft linear PNIPAM chains into the pores of the microcapsule membranes. In the SPG membrane emulsification process, theoptimumsurfactant sodium dodecyl sulfate (SDS) concentrationandpoly (vinyl alcohol) stabilizer concentration could be selected by solely considering the monodispersity of the emulsion droplets. However, before the interfacial polymerization process was started, these two oncentrations needed to be monitored to avoid any aggregation of the microcapsules and, if necessary, the appropriate quantity of SDS or Tween 80 needed to be added to prevent the microcapsules from aggregating in the interfacial polymerization stage. The prepared PNIPAM-grafted monodispersed microcapsules with a mean diameter of about 4μm showed satisfactory reversible and reproducible thermoresponsive release characteristics. The release of both NaCl and vitamin B12 (VB12) from the PNIPAM-grafted microcapsules was slow at 25℃ and fast at 40℃, which is due to the closed/open state of the grafted "gates". The "on/off" ratio of the release rate of VB12 from the PNIPAM-grafted microcapsules was much larger than that of NaCl.

A thermo-responsive core-shell microcapsule with a porous membrane and poly (N-isopropylacrylamide) (PNIPAM) gates was prepared using interfacial polymerization to prepare polyamide core-shell microcapsules, and plasma-graft pore-filling polymerization to graft PNIPAMinto the pores in the microcapsule wall. The proposed thermo-responsive microcapsule could be a positive thermo-response controlled-release one or a negative thermo-response one by changing the PNIPAM graft yield. When the graft yield is low, the release rate from the microcapsules is higher at temperatures above the lower critical solution temperature (LCST) than that below the LCST, due to the opened/closed pores in the microcapsule membranes controlled by the PNIPAM gates. In contrast, when the graft yield is high, the release rate is lower at temperatures above the LCST than that below the LCST, due to the hydrophilic/hydrophobic phase transition of the PNIPAM gates.

The pore size and permeability control of a glucose-responsive gating membrane with plasma-grafted poly (acrylic acid) (PAAC) gates and covalently bound glucose oxidase (GOD) enzymes were investigated systematically. The PAAC-grafted porous polyvinylidene fluoride (PVDF) membranes with a wide range of grafting yields were prepared using a plasma-graft pore-filling polymerization method, and the immobilization of GOD was carried out by a carbodiimide method. The linear grafted PAAC chains in the membrane pores acted as the pH-responsive gates or actuators. The immobilized GOD acted as the glucose sensor and catalyzer; it was sensitive to glucose and catalyzed the glucose conversion to gluconic acid. The experimental results showed that the glucose responsivity of the solute diffusional permeability through the proposed membranes was heavily dependent on the PAAC grafting yield, because the pH-responsive change of pore size governed the glucose-responsive diffusional permeability. It is very important to design a proper grafting yield for obtaining an ideal gating response. For the proposed gating membrane with a PAAC grafting yield of 1.55%, the insulin permeation coefficient after the glucose addition (0.2mol/l) was about 9.37 times that in the absence of glucose, presenting an exciting result on glucosesensitive self-regulated insulin permeation.

In this paper, we report on a novel family of monodisperse thermo-sensitive core-shell hydrogel microspheres that is featured with high monodispersity and positively thermo-responsive volume phase transition characteristics with tunable swelling kinetics, i.e., the particle swelling is induced by an increase rather than a decrease in temperature. The microspheres were fabri-cated in a three-step process. In the first step, monodisperse poly(acrylamide-co-styrene) seeds were prepared by emulsifier-free emulsion polymerization. In the second step, poly(acrylamide) or poly[acrylamide-co-(butyl methacrylate)] shells were fabricated on the microsphere seeds by free radical polymerization. In the third step, the core-shell microspheres with poly-(acrylamide)/poly(acrylic acid) based interpenetrating polymer network (IPN) shells were finished by a method of sequential IPN synthesis. The proposed monodisperse core-shell microspheres provide a new mode of the phase transition behavior for thermo-sensitive "smart" or "intelligent" monodisperse micro-actuators that is highly attractive for targeting drug delivery sys-tems, chemical separations, sensors, and so on.