title: 3D culture of bone-derived cells immobilised in alginate following light-triggered gelation.
abstract: Photoreactive liposomes have been exploited as a means of developing 3D tissue constructs. Liposomes formulated using the photosensitive lipid 1,2-bis(4-(n-butyl)phenylazo-4'-phenylbutyroyl)phosphatidylcholine (Bis Azo PC), which undergoes conformational change on stimulation with long wavelength ultraviolet light, were prepared with entrapped CaCl(2) before being incorporated into a 4% alginate solution. It was shown that stimulation of the photosensitive lipid using a light emitting diode (LED) (peak emission at 385 nm, dose equivalent to 9 mJ/cm(2)) caused the release of liposome-entrapped CaCl(2), resulting in cross-linking of the alginate solution and immobilisation of bone-derived cells over a range of seeding densities, approximately 97% of which remained viable for periods of up to 14 days in culture. Entrapment volumes of a variety of liposome types were evaluated and interdigitating fusion vesicles were identified as having the highest payload (24%), however the inclusion of cholesterol as a means of shifting Bis Azo PC sensitivity into the visible light wavelengths resulted in an approximately 10-fold reduction in calcium entrapment. This application of light-sensitised liposomes offers the potential to create complex tissue engineering substrates containing cells immobilised in precise locations, in contrast with substrates onto which cells are seeded post-production.
authors.affiliation: Biomaterials Unit, School of Dentistry, University of Birmingham, St Chad's Queensway, Birmingham, UK.
authors.forename: Alan M
authors.initials: AM
authors.lastname: Smith
authors.forename: Jonathan J
authors.initials: JJ
authors.lastname: Harris
authors.forename: Richard M
authors.initials: RM
authors.lastname: Shelton
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Perrie
mesh_terms: D000464:Alginates / Q000493:pharmacokinetics*; D000818:Animals; D001854:Bone Marrow Cells / Q000187:drug effects / Q000502:physiology; D018929:Cell Culture Techniques / Q000379:methods*; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D004337:Drug Carriers; D005782:Gels / Q000493:pharmacokinetics*; D020723:Glucuronic Acid / Q000493:pharmacokinetics; D006603:Hexuronic Acids / Q000493:pharmacokinetics; D010775:Photic Stimulation / Q000379:methods*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D000464:Alginates; D004337:Drug Carriers; D005782:Gels; D006603:Hexuronic Acids; D020723:Glucuronic Acid