title: A layer-by-layer approach to natural polymer-derived bioactive coatings on magnesium alloys.
abstract: The development of polyelectrolyte multilayered coatings on magnesium alloy substrates that can be used for controlled delivery of growth factors and required biomolecules from the surface of these degradable implants could have a significant impact in the field of bone tissue regeneration. The current work reports on the fabrication of multilayered coatings of alginate and poly-L-lysine on alkaline- and fluoride-pretreated AZ31 substrates using a layer-by-layer (LbL) technique under physiological conditions. Furthermore, these coatings were surface functionalized by chemical cross-linking and fibronectin immobilization, and the resultant changes in surface properties have been shown to influence the cellular activity of these multilayered films. The physicochemical characteristics of these coated substrates have been investigated using attenuated total reflectance Fourier transform infrared spectroscopy, atomic force microscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy. Cytocompatibility studies using MC3T3-E1 osteoblasts show that the fluoride-pretreated, cross-linked and fibronectin-immobilized LbL-coated substrates are more bioactive and less cytotoxic than the hydroxide-pretreated, cross-linked and fibronectin-immobilized LbL-coated samples. The in vitro degradation results show that the multilayered coatings of these natural polysaccharide- and synthetic polyamino acid-based polyelectrolytes do not alter the degradation kinetics of the substrates; however, the pretreatment conditions have a significant impact on the overall coating degradation behavior. These preliminary results collectively show the potential use of LbL coatings on magnesium-based degradable scaffolds to improve their surface bioactivity.
authors.affiliation: Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261, USA.
authors.forename: Sangeetha
authors.initials: S
authors.lastname: Kunjukunju
authors.forename: Abhijit
authors.initials: A
authors.lastname: Roy
authors.forename: Madhumati
authors.initials: M
authors.lastname: Ramanathan
authors.forename: Boeun
authors.initials: B
authors.lastname: Lee
authors.forename: Joe E
authors.initials: JE
authors.lastname: Candiello
authors.forename: Prashant N
authors.initials: PN
authors.lastname: Kumta
mesh_terms: D000497:Alloys / Q000494:pharmacology*; D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D020099:Coated Materials, Biocompatible / Q000494:pharmacology*; D003343:Corrosion; D004247:DNA / Q000378:metabolism; D055664:Electrochemical Techniques; D006859:Hydrogen / Q000032:analysis; D008274:Magnesium / Q000494:pharmacology*; D051379:Mice; D018625:Microscopy, Atomic Force; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D010012:Osteogenesis / Q000187:drug effects; D011108:Polymers / Q000494:pharmacology*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000497:Alloys; D020099:Coated Materials, Biocompatible; D011108:Polymers; D006859:Hydrogen; D004247:DNA; D008274:Magnesium
keywords: Biodegradation; Coating; Corrosion; Layer by layer; Magnesium; Polyelectrolytes