title: Photo-control of the interaction between endothelial cells and photo-cation generatable water-soluble polymers.
abstract: In this study photo-control of the non-biospecific interaction between endothelial cell membranes and photo-cation generatable water-soluble polymers were examined. The water-soluble polymers contained triphenylmethane leucohydroxide (malachite green) groups (contents: 0.4 and 1.6 mol%), which dissociate into triphenylmethyl cations and counter hydroxide ions upon ultraviolet light (UV) irradiation, and were prepared by free radical copolymerization of diphenyl(4-vinylphenyl)methane leucohydroxide and acrylamide. The nature and magnitude of the interaction was quantitatively assessed by direct luminescence measurement of the intracellular calcium ion concentration using a calcium-sensitive photoprotein, aequorin. When a PBS buffer of the photoreactive copolymers were added, prior to UV irradiation, to a PBS suspension of cultured bovine endothelial cells loaded with aequorin, no detectable elevation of Ca(2+) was measured. In contrast, cationic copolymers, derived from the photoreactive copolymers after UV irradiation at a wavelength of 290<lambda<410 nm, induced an immediate transient increase in the cytosolic free Ca(2+) concentration due to a Ca(2+) inflow from the extracellular space into the cells, which may be due to non-biospecific transmembrane stimulation. Longer UV irradiation exposures of the copolymers and higher concentrations of the polymers, with higher contents of the photodissociable group, resulted in more Ca(2+) inflow with little cellular damage. The photo-cation generatable copolymers developed here made possible to control the non-biospecific interaction with endothelial cell membranes by UV irradiation condition, and composition and amount of the copolymer.
authors.affiliation: Department of Bioengineering, National Cardiovascular Center Research Institute, 5-7-1 Fujishiro-dai, Suita, Osaka 565-8565, Japan. nakayama@ri.ncvc.go.jp
authors.forename: Yasuhide
authors.initials: Y
authors.lastname: Nakayama
authors.forename: Takehisa
authors.initials: T
authors.lastname: Matsuda
mesh_terms: D000818:Animals; D002412:Cations / Q000378:metabolism / Q000528:radiation effects; D002417:Cattle; D042783:Endothelial Cells / Q000378:metabolism* / Q000528:radiation effects*; D011108:Polymers / Q000493:pharmacokinetics* / Q000528:radiation effects*; D012995:Solubility; D014466:Ultraviolet Rays; D014867:Water / Q000378:metabolism
chemical_list: D002412:Cations; D011108:Polymers; D014867:Water