Ionic strength-sensitive pullulan acetate nanoparticles (PAN) for intratumoral administration of radioisotope: ionic strength-dependent aggregation behavior and (99m)Technetium retention property.

In order to design an effective intratumoral radioisotope carrier, a self-assembled nanoparticle evidencing ionic strength (IS)-sensitivity from a polysaccharide derivative (pullulan acetate nanoparticle (PAN)) was prepared via dialysis. The PAN had a spherical shape in a range of size of 50-130 nm and a low critical aggregation concentration (CAC) (<8 microg/mL). With increases in the IS of the dialysis media (IS(dia)), the CAC of PAN was reduced gradually and the rigidity of the hydrophobic core in PAN was increased.

Morphology of spheroidal hepatocytes within injectable, biodegradable, and thermosensitive poly(organophosphazene) hydrogel as cell delivery vehicle.

An aggregate of specific cells is often regarded as a better form of single-cell in artificial organs and mammalian cell bioreactors for improved cell-specific functions. In this study, freshly harvested primary rat hepatocytes, cultivated as spheroids and entrapped in a synthetic thermoreversible extracellular matrix, were examined for differentiation morphology and enhanced liver-specific functions and compared with a control set (single-cell hepatocytes). A copolymer of poly(organophsophazene) hydrogel, an injectable, biodegradable, and thermosensitive matrix, was used to entrap hepatocytes as spheroids or single cells.

Specific interaction of mannosylated glycopolymers with macrophage cells mediated by mannose receptor.

Poly[N-p-vinylbenzyl-O-beta-mannopyranosyl-(1-4)-D-gluconamide] (PV-Man) is a polystyrene derivative that contains mannose moieties and interacts with the mannose-receptor-carrying macrophage cell line. To clarify the specific interaction between the PV-Man and the macrophage cell line J774A1, PV-Man polymer labeled with fluorescent fluorescein isothiocyanate (FITC) was used to amonitor the specific interaction, which was visualized by confocal laser microscopy. We found that PV-Man strongly binds to macrophage cells, probably due to a specific interaction mediated by the presence of mannose receptors on the cell membrane.

Phenotype of hepatocyte spheroids behavior within thermo-sensitive poly(NiPAAm-co-PEG-g-GRGDS) hydrogel as a cell delivery vehicle.

Aggregates (spheroids) of specific cells are often regarded as a better form in artificial organs and mammalian cell bioreactors for improved cell-specific functions. Freshly harvested primary rat hepatocytes, cultivated as spheroids and entrapped in an adhesion molecules of Arg-Gly-Asp (RGD)-conjugated extracellular matrix, have been examined for differentiated morphology and enhanced liver-specific functions. A copolymer of RGD conjugated p(NiPAAm-co-PEG) hydrogel was used to entrap hepatocytes in the forms of spheroids.

Probing of specific binding of synthetic sulfonylurea with the insulinoma cell line MIN6.

To overcome the limitation of conventional sulfonylurea (SU) for investigation of biological mechanisms related to KATP channels, a hypoglycemic sulfonylurea (SU) was conjugated with a non-reducing glucose bearing polystyrene (PS) derivative to provide enhanced interaction with an insulinoma cell line (MIN6). The specific interaction between the SU (K+ channel closer)-conjugated copolymer and MIN6 cells was confirmed by confocal laser microscopic images using rhodamine B isothiocyanate (RITC)-labeled SU-conjugated polymer, which revealed the specific interaction between SU-conjugated polymer and MIN6 cells. Moreover, the location of labeled polymer and the site of Ca2+ ion mobilization obtained from the same MIN6 cells were identical.

Enhancement of the adhesion of fibroblasts by peptide containing an Arg-Gly-Asp sequence with poly(ethylene glycol) into a thermo-reversible hydrogel as a synthetic extracellular matrix.

In an effort to regulate the behavior of mammalian cell entrapped in a gel, the gels were functionalized with the putative cell-binding (-Arg-Gly-Asp-) (RGD) domain. The adhesion molecules composed of Gly-Arg-Gly-Asp-Ser (GRGDS) peptides and the cell recognition ligands were inculcated into the thermo-reversible hydrogel composed of N-isopropylacrylamide, with a small amount of succinyl poly(ethylene glycol) (PEG) acrylate (MW 2000) used as the biomimetic extracellular matrix (ECM). The GRGDS-containing p(NiPAAm-co-PEG) copolymer gel was examined in vitro for its ability to promote cell spreading and to increase the viability of the cells by introducing PEG spacers.

Synthesis of Arg-Gly-Asp (RGD) sequence conjugated thermo-reversible gel via the PEG spacer arm as an extracellular matrix for a pheochromocytoma cell (PC12) culture.

Adhesion molecules composed of Gly-Arg-Gly-Asp-Ser (GRGDS) peptides and cell recognition ligands were inculcated into thermo-reversible hydrogel composed of N-isopropylacrylamide, with a small amount of succinyl poly(ethylene glycol) (PEG) acrylate (MW 3400) used as a biomimetic extracellular matrix (ECM). The GRGDS-containing p(NiPAAm-co-PEG) copolymer gel was studied in vitro for its ability to promote cell spreading and to increase the viability of cells by introducing PEG spacers. Hydrogel lacking the adhesion molecules proved to be a poor ECM for adhesion, permitting only a 20% spread of the seeded cells after 10 days.