title: Low-fouling, biofunctionalized, and biodegradable click capsules.
abstract: We report the synthesis of covalently stabilized hollow capsules from biodegradable materials using a combination of click chemistry and layer-by-layer (LbL) assembly. The biodegradable polymers poly(L-lysine) (PLL) and poly(L-glutamic acid) (PGA) were modified with alkyne and azide moieties. Linear film buildup was observed for both materials on planar surfaces and colloidal silica templates. A variation of the assembly conditions, such as an increase in the salt concentration and variations in pH, was shown to increase the individual layer thickness by almost 200%. The biodegradable click capsules were analyzed with optical microscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). Capsules were uniform in size and had a regular, spherical shape. They were found to be stable between pH 2 and 11 and showed reversible, pH-responsive shrinking/swelling behavior. We also show that covalently stabilized PLL films can be postfunctionalized by depositing a monolayer of heterobifunctional poly(ethylene glycol) (PEG), which provides low-fouling properties and simultaneously enhances specific protein binding. The responsive, biodegradable click films reported herein are promising for a range of applications in the biomedical field.
authors.affiliation: Centre for Nanoscience and Nanotechnology, Department of Chemical and Biomolecular Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Ochs
authors.forename: Georgina K
authors.initials: GK
authors.lastname: Such
authors.forename: Brigitte
authors.initials: B
authors.lastname: Städler
authors.forename: Frank
authors.initials: F
authors.lastname: Caruso
mesh_terms: D001672:Biocompatible Materials / Q000138:chemical synthesis* / Q000737:chemistry*; D002214:Capsules / Q000138:chemical synthesis* / Q000737:chemistry*; D003102:Colloids / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D008856:Microscopy, Fluorescence; D015394:Molecular Structure; D011092:Polyethylene Glycols / Q000737:chemistry; D011099:Polyglutamic Acid / Q000737:chemistry; D011107:Polylysine / Q000737:chemistry; D013499:Surface Properties
chemical_list: D001672:Biocompatible Materials; D002214:Capsules; D003102:Colloids; D011107:Polylysine; D011099:Polyglutamic Acid; D011092:Polyethylene Glycols