title: DNA encapsulation within co-guanidine membrane coated alginate beads and protection from extracapsular nuclease.
abstract: Co-guanidine membranes were shown to form intact, ionically complexed membranes on alginate beads, serving as an alternative to the commonly used polymers, poly-L-lysine and chitosan. DNA was encapsulated and membrane thickness, the level of DNA protection from nuclease diffusion and the degree of DNA-complexation with co-guanidine membranes were all shown to be dependent on both polymer concentration and coating time. The highest level of DNAse exclusion was possible within beads coated with a polymer concentration of 5 mg/ml. Recovery of double-stranded DNA after nuclease exposure for 60 min reached 90% of that initially encapsulated. The molecular weight cut-off for these co-guanidine membranes was approximately 31 kDa, sufficient to exclude extracapsular nuclease. The level of DNA protection was found to be comparable to high molecular weight poly-L-lysine membranes (197.1 kDa). Intracapsular DNA was accessible to the carcinogen ethidium bromide, which showed a 4-fold increase in uptake in uncoated beads and 2-fold uptake in co-guanidine coated beads compared to beads lacking in DNA. Co-guanidine membranes coating alginate result in a molecular weight cut-off sufficient to retain DNA and exclude 31 kDa DNAse, while providing access to the low molecular weight carcinogen, ethidium bromide.
authors.affiliation: Department of Chemical Engineering, McGill University, Montréal, Québec, Canada.
authors.forename: D
authors.initials: D
authors.lastname: Quong
authors.forename: R J
authors.initials: RJ
authors.lastname: Neufeld
mesh_terms: D000464:Alginates / Q000008:administration & dosage / Q000737:chemistry*; D002273:Carcinogens / Q000378:metabolism; D020099:Coated Materials, Biocompatible / Q000008:administration & dosage / Q000737:chemistry*; D004247:DNA / Q000008:administration & dosage* / Q000737:chemistry* / Q000378:metabolism; D003851:Deoxyribonucleases / Q000378:metabolism*; D004996:Ethidium / Q000378:metabolism; D020723:Glucuronic Acid; D019791:Guanidine / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000737:chemistry*; D006146:Guanidines / Q000008:administration & dosage / Q000737:chemistry*; D006603:Hexuronic Acids; D007700:Kinetics; D008567:Membranes, Artificial; D011073:Polyamines / Q000008:administration & dosage / Q000737:chemistry*; D011108:Polymers / Q000008:administration & dosage / Q000737:chemistry; D016062:Porosity
chemical_list: D000464:Alginates; D002273:Carcinogens; D020099:Coated Materials, Biocompatible; D006146:Guanidines; D006603:Hexuronic Acids; D008567:Membranes, Artificial; D011073:Polyamines; D011108:Polymers; C402176:poly(hexamethylene-co-guanidine); C402175:poly(methylene-co-guanidine); D020723:Glucuronic Acid; D004247:DNA; D003851:Deoxyribonucleases; D004996:Ethidium; D019791:Guanidine