To introduce a phosphorylcholine (PC) moiety into segmented polyurethane, which has been widely used as an elastic material, the synthesis of a novel diol monomer containing a PC unit was performed. PC-containing polyurethanes were then prepared by polyaddition of the diol monomer and poly(carbonate diol) with 4,4 0 -diphenylmethane diisocyanate. The obtained polyurethanes were soluble in aprotic polar solvents, such as N,N-dimethylacetamide, N,N-dimethylformamide (DMF) and dimethyl sulfoxide, but were insoluble in water and alcohol. According to thermal analysis and the stress-strain measurements, the polyurethane films exhibited thermal stability up to 250 1C and elastic properties with high tensile strength. In addition, it was confirmed from the results of the protein adsorption experiments that the PC-containing polyurethane films efficiently reduced protein adsorption to the surface. Japan (SPSJ) All rights reserved 0032-3896/13 www.nature.com/pj
The syntheses of novel polyesters and poly(ester-urethane)s containing phosphorylcholine (PC) group was carried out. The obtained polymers were soluble in aprotic polar solvents such as DMSO and NMP. By the way, the copolyesters containing polycarbonate segment showed the better solubility than the homopolyester, which were soluble in the low boiling point solvents such as THF and chloroform. Furthermore, the obtained polymers showed the high thermal stability up to 250°C, at which the thermal degradation of PC moiety occurred. In particular, the self-standing polymer films could be prepared from poly(ester-urethane). The poly(ester-urethane) films exhibited the elastic properties with high tensile strength, therefore, these polymers could be expected as elastic biocompatible materials for the use of biomedical devices.
Cationic
magnetic hydrogel microparticles with high retention on
cell surfaces were prepared using a two-step procedure. Using these
magnetic hydrogel microparticles, cells were clustered with each other,
and cell aggregates were prepared effectively. Cross-linked poly(vinyl
alcohol) (PVA) hydrogel microparticles containing iron oxide nanoparticles
were prepared. The diameter of the microparticles was in the range
of 200–500 nm. Water-soluble cationic polymers containing both
trimethyl ammonium (TMA) groups and phenylboronic acid (PBA) groups
were synthesized for the surface modification of the microparticles.
To regulate the composition, electrically neutral phosphorylcholine
groups were introduced into the polymer. Covalent bonds were formed
between the hydroxy groups of PVA microparticles and PBA groups in
the polymer. The surface zeta potential of the microparticles reflected
the composition of the TMA groups. The particles responded to an external
magnetic field and clustered rapidly. Microparticles were adsorbed
on the floating cell surface and induced cell aggregation quickly
when a magnetic field was applied. Under the most effective conditions,
the diameter of the cell aggregates increased to approximately 1 mm
after 30 min. Denser cell aggregates were formed by the synergistic
effects of the magnetic field and the properties of the microparticles.
The formed cell aggregates continued to grow for more than 4 days
under an applied magnetic field, indicating that the ability of the
cells in the aggregate to proliferate was well maintained.
The preparation of soluble polyamides, poly(amide-ester) and poly(urethane-urea) containing phosphorylcholine (PC) group was carried out by the polycondensation and polyaddition using an aromatic diamine monomer containing a phospholipid polar group. In the syntheses of poly(amideester) and poly(urethane-urea), polycarbonatediol was used as a comonomer to insert a soft segment. The self-standing elastic polymer films could be fabricated from the obtained PC-containing copolymers by the solvent-casting method. In particular, polymer films fabricated from poly(urethane-urea) exhibited the elastic properties similar to commercially available poly(carbonate-urethane), bionate μ . It was found that the PC-containing polymer films sufficiently reduced the adhesion of proteins and platelets. Therefore, it was shown that the obtained polymers possess both, high biocompatibility derived from PC group and the elastic properties derived from the main chain structure. KEY WORDS Phosphorylcholine / Polycondensation / Polyaddition / Biocompatibility / Elastomer / (
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