title: Preparation and characterization of PEM-coated alginate microgels for controlled release of protein.
abstract: In this study, calcium-alginate microgels coated with a polyelectrolyte multilayer (PEM) were fabricated as a controlled-release system. This system was constructed via an electrostatic droplet generation technique followed by a layer-by-layer (LbL) self-assembly technique. The electrostatic droplet generation technique was reported as an easy method of preparing microgels, due to their mild preparation conditions and ability to preserve the biological activity of the encapsulated drugs. With the LbL self-assembly technique, the PEM could be fabricated on the microgels attributed to the electrostatic attraction between positive-charged chitosan (Chi) and negative-charged dextran sulfate (Dex). The properties of the prepared microgels were investigated using dynamic laser scattering (DLS), scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectrum and zeta potential analyzer. In vitro release study indicated that the initial burst release of the bovine serum albumin (BSA) from PEM-coated microgels was less compared to the uncoated microgels (19% versus 31% in 24 h). In addition, the sustained release of BSA from the PEM-coated microgels was recorded up to 1 month without any damage to BSA integrity. Thus, our results demonstrated that the PEM-coated microgels not only prolonged the release time, but also relieved the initial burst problem to some degree and preserved the biological activity of the encapsulated drugs. Moreover, the release rate of BSA could be regulated by controlling the number of deposited layers. In conclusion, this study presented an easy yet effective method for the controlled, sustained release of biological macromolecules.
authors.affiliation: Institutes of Biomedical Engineering, College of Life Science and Technology, Jinan University, Guangzhou 510632, People's Republic of China.
authors.forename: Qinhua
authors.initials: Q
authors.lastname: Zuo
authors.forename: Jianbo
authors.initials: J
authors.lastname: Lu
authors.forename: An
authors.initials: A
authors.lastname: Hong
authors.forename: Dagen
authors.initials: D
authors.lastname: Zhong
authors.forename: Shasha
authors.initials: S
authors.lastname: Xie
authors.forename: Quan
authors.initials: Q
authors.lastname: Liu
authors.forename: Yuexin
authors.initials: Y
authors.lastname: Huang
authors.forename: Yunfeng
authors.initials: Y
authors.lastname: Shi
authors.forename: Liumin
authors.initials: L
authors.lastname: He
authors.forename: Wei
authors.initials: W
authors.lastname: Xue
mesh_terms: D000464:Alginates / Q000737:chemistry*; D000818:Animals; D002417:Cattle; D020099:Coated Materials, Biocompatible / Q000138:chemical synthesis*; D003692:Delayed-Action Preparations / Q000737:chemistry*; D004058:Diffusion; D004573:Electrolytes / Q000737:chemistry*; D005782:Gels / Q000737:chemistry*; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D008422:Materials Testing; D012710:Serum Albumin, Bovine / Q000737:chemistry*
chemical_list: D000464:Alginates; D020099:Coated Materials, Biocompatible; D003692:Delayed-Action Preparations; D004573:Electrolytes; D005782:Gels; D006603:Hexuronic Acids; D012710:Serum Albumin, Bovine; D020723:Glucuronic Acid