title: Poloxamine hydrogels with a quaternary ammonium modification to improve cell attachment.
abstract: Four-arm poly(ethylene oxide) and poly(propylene oxide) (PEO-PPO) block copolymer (poloxamine, Tetronic 1107) hydrogels were modified with positively charged groups with the aim of overcoming the low cell adhesion properties of these PEO-rich systems. Different matrices containing poloxamine-methacrylate (6-12%) and a quaternary ammonium methacrylate ([2-(methacryloyloxy)ethyl]-trimethylammonium chloride [MAETAC], 0-0.48 M) were produced by a photo-initiated free radical copolymerization. A sharp increase in water content for MAETAC-containing gels was seen during the first 2 days of incubation in distilled water; some of the gels showed water uptakes as high as 12 times the initial wet weight. In phosphate-buffered saline (PBS), this effect was less pronounced because of the decrease in the osmotic gradient. In addition, a gradual increase of both the storage and the loss modulus of the gels resulted from increasing the MAETAC content [e.g., G' values increased from 13,500 Pa for 12% poloxamine-methacrylate gels without MAETAC to 151,000 Pa for 0.48M MAETAC contents (at 1 Hz, 100 Pa of oscillatory stress)]. Although on pure poloxamine-methacrylate gels HepG2 and HUVEC cells attached poorly, on MAETAC-containing specimens a well-spread morphology and confluent monolayers were obtained, at least after preincubation in serum containing medium. Although not having all the cell compatibility of collagen, these fully synthetic quaternary ammonium-modified PEO-rich gels may have some utility in tissue-engineering applications where stiff gels and cell attachment after gelation are desired.
authors.affiliation: Department of Chemical Engineering and Applied Chemistry, Institute of Biomaterials and Biomedical Engineering, University of Toronto, 4 Taddle Creek Road, Room 407D, Toronto, Ontario, Canada M5S 3G9.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Sosnik
authors.forename: Michael V
authors.initials: MV
authors.lastname: Sefton
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry* / Q000378:metabolism; D002448:Cell Adhesion / Q000502:physiology*; D018929:Cell Culture Techniques; D045744:Cell Line, Tumor; D005029:Ethylenediamines / Q000737:chemistry* / Q000378:metabolism; D005109:Extracellular Matrix / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D020100:Hydrogels / Q000737:chemistry* / Q000378:metabolism; D008422:Materials Testing; D015394:Molecular Structure; D000644:Quaternary Ammonium Compounds / Q000737:chemistry* / Q000378:metabolism; D013499:Surface Properties
chemical_list: D001672:Biocompatible Materials; D005029:Ethylenediamines; D020100:Hydrogels; D000644:Quaternary Ammonium Compounds