Covalent immobilization of trypsin onto poly(2-hydroxyethyl methacrylate)/ polystyrene composite microspheres, produced by emulsifier-free seeded emulsion polymerization technique, was carried out using the cyanogen bromide method under various conditions. The highest enzymatic activities of the trypsin immobilized in this study against N-u-benzoyl-L-arginine ethyl ester and N-ce-benzoyl-L-arginine-p-nitroanilide, as low-molecular substrates and casein as a high-molecular substrate, were high, as corresponding to 80 %, 85 % and 50 % of those of free trypsin, respectively.
Poly(trimethylene carbonate) (PTMC) shows biodegradability and is currently being utilized in medical devices. In this study, poly(ethylene glycol) monomethyl ether (mPEG) was incorporated into the terminating end of a PTMC molecule. mPEG, which has a hydrophilic segment, was selected as the initiator. Two kinds of mPEG with average molecular weight 5000 g/mol and 350 g/mol was used.The resulting polymer spontaneously aggregated in the organic solvent. The aggregations were quite stable for 2 months at room temperature. The composition, the hydrophilic and hydrophobic segment, was dominant factor to regulate the stability of polymer aggregation. The time to reach complete dissociation was variable, and the stability of the polymer aggregation was more than 1 month. The difference in its stability would depend on its circulation in our body for 2 months because of the difference in its degree of polymerization and composition. Moreover, the drug loading property using the resulting aggregations was examined using Basic Blue17, which is an organic dye and is used as a model substance. We have found that the organic dye was successfully loaded into the aggregations.
Biodegradable polymers can be used in living systems. One such biodegradable polymer that has attracted considerable attention in recent years is poly(trimethylene carbonate) (PTMC). In this study, poly(ethylene glycol) monomethyl ether (mPEG), which has hydrophilic properties, was used as the initiator for PTMC synthesis. The mPEG-PTMC block copolymer exhibits amphiphilicity and forms a very stable aggregation in a solvent. In our previous study, mPEG-PTMC aggregations that remained stable for two months in a methanol solvent were prepared. In the present study, the aggregation of this polymer could be maintained in a stable state for 1 year in ultrapure water owing to the hydrophilic segment of mPEG. Additionally, examination of the encapsulation properties of the aggregation was also performed using 8-anilino-1-naphthalenesulfonic acid. Encapsulation of the aggregation caused the intensity of the fluorescence to become high and the maximum fluorescence wavelength to shift to the short wavelength resion with increasing polymer concentration. The high stability and encapsulation property of this aggregation will facilitate application of this polymer to drug delivery systems.
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