title: Investigation of mechanical properties of soft hydrogel microcapsules in relation to protein delivery using a MEMS force sensor.
abstract: This article reports the investigation of mechanical properties of alginate-chitosan microcapsules and the relation to protein delivery. For microscale compression testing, a system based on a microelectromechanical systems (MEMS) capacitive force sensor was developed. The bulk microfabricated capacitive force sensors are capable of resolving forces up to 110 microN with a resolution of 33.2 nN along two independent axes. The monolithic force sensors were directly applied to characterizing mechanical properties of soft hydrogel microparticles without assembling additional end-effectors. Protein-loaded alginate-chitosan microcapsules of approximately 20 mum in diameter were prepared by an emulsion-internal gelation-polyelectrolyte coating method. Young's modulus values of individual microcapsules with 1, 2, and 3% chitosan coating were determined through microscale compression testing in both distilled deionized (DDI) water and pH 7.4 phosphate-buffered saline (PBS). Protein release rates were also determined in DDI water and PBS. Finally, protein release rates were correlated with mechanical properties of the microcapsules.
authors.affiliation: Advanced Micro and Nanosystems Laboratory, University of Toronto, 5 King's College Road, Toronto, Ontario, Canada.
authors.forename: Keekyoung
authors.initials: K
authors.lastname: Kim
authors.forename: Ji
authors.initials: J
authors.lastname: Cheng
authors.forename: Qun
authors.initials: Q
authors.lastname: Liu
authors.forename: Xiao Yu
authors.initials: XY
authors.lastname: Wu
authors.forename: Yu
authors.initials: Y
authors.lastname: Sun
mesh_terms: D000464:Alginates / Q000494:pharmacology; D001696:Biomechanical Phenomena / Q000187:drug effects; D015374:Biosensing Techniques / Q000295:instrumentation*; D002138:Calibration; D002214:Capsules; D048271:Chitosan / Q000494:pharmacology; D055119:Elastic Modulus / Q000187:drug effects; D005949:Glucose Oxidase / Q000378:metabolism*; D020723:Glucuronic Acid / Q000494:pharmacology; D006603:Hexuronic Acids / Q000494:pharmacology; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000737:chemistry*; D007700:Kinetics; D008422:Materials Testing; D055617:Micro-Electrical-Mechanical Systems / Q000295:instrumentation*; D008855:Microscopy, Electron, Scanning
chemical_list: D000464:Alginates; D002214:Capsules; D006603:Hexuronic Acids; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D020723:Glucuronic Acid; D048271:Chitosan; D005949:Glucose Oxidase