title: Encapsulation of DNA in macroscopic and nanosized calcium alginate gel particles.
abstract: Calcium alginate beads, which are biodegradable and biocompatible, have been widely employed as delivery matrices for biomacromolecules. In the present work, the feasibility of encapsulation of DNA (which is used as a model biomacromolecule) in calcium alginate nanobeads (sub-200 nm size), prepared using a recently developed protocol based on the phase inversion temperature (PIT) emulsification method [Machado et al. Langmuir 2012, 28, 4131-4141], was assessed. The properties of the nanobeads were compared to those of the corresponding macroscopic (millimeter sized) calcium alginate beads. It was found that DNA, representing a relatively stiff and highly charged polyanion (thus like-charged to alginate), could be efficiently encapsulated in both nanosized and macroscopic beads, with encapsulation yields in the range of 77-99%. Complete release of DNA from the beads could be accomplished on dissolution of the gel by addition of a calcium-chelating agent. Importantly, the DNA was not denatured or fragmented during the preparation and collection of the nanobeads, which are good indicators of the mildness of the preparation protocol used. The calcium alginate nanobeads prepared by the herein utilized protocol thus show good potential to be used as carriers of sensitive biomacromolecules.
authors.affiliation: Division of Physical Chemistry, Center for Chemistry and Chemical Engineering, Lund University , P.O. Box 124, SE-221 00 Lund, Sweden.
authors.forename: Alexandra H E
authors.initials: AH
authors.lastname: Machado
authors.forename: Dan
authors.initials: D
authors.lastname: Lundberg
authors.forename: António J
authors.initials: AJ
authors.lastname: Ribeiro
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Veiga
authors.forename: Maria G
authors.initials: MG
authors.lastname: Miguel
authors.forename: Björn
authors.initials: B
authors.lastname: Lindman
authors.forename: Ulf
authors.initials: U
authors.lastname: Olsson
mesh_terms: D000464:Alginates / Q000737:chemistry*; D002214:Capsules; D004247:DNA / Q000737:chemistry*; D005240:Feasibility Studies; D005782:Gels; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry*; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: D000464:Alginates; D002214:Capsules; D005782:Gels; D006603:Hexuronic Acids; D014867:Water; D020723:Glucuronic Acid; D004247:DNA