title: Calcification-resistant Nafion/Fe3+ assemblies for implantable biosensors.
abstract: An electrostatic layer-by-layer deposition technique was employed for the formation of thin films consisting of alternating layers of perfluorinated ionomer (Nafion) and ferric ions. UV-vis spectroscopic and ellipsometric data indicate a stepwise growth that in certain cases is as high as 47 nm per dip cycle. The growth characteristics of these assemblies can be correlated with Nafion's hydrodynamic radius, iron content, as well as the ionic strength and pH of Nafion and the wash solution. When these assemblies were compared to cast Nafion films, they exhibit the following advantages: (i) increased hydrolytic stability, attained without thermal treatment required for pristine Nafion films, and (ii) resistance to calcification, by more than an order of magnitude. These results, along with the ability to control glucose permeability by varying the number of Nafion/Fe3+ layers, could prove vital in prolonging the lifetime of implantable biosensors.
authors.affiliation: Department of Chemistry, Polymer Science Program, Nanomaterials Optoelectronic Laboratory, Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269, USA.
authors.forename: I
authors.initials: I
authors.lastname: Galeska
authors.forename: D
authors.initials: D
authors.lastname: Chattopadhyay
authors.forename: F
authors.initials: F
authors.lastname: Moussy
authors.forename: F
authors.initials: F
authors.lastname: Papadimitrakopoulos
mesh_terms: D000465:Algorithms; D015374:Biosensing Techniques; D002118:Calcium / Q000737:chemistry*; D005465:Fluorocarbon Polymers / Q000737:chemistry*; D005947:Glucose / Q000737:chemistry; D007202:Indicators and Reagents; D007501:Iron / Q000737:chemistry*; D008027:Light; D008567:Membranes, Artificial; D010539:Permeability; D012542:Scattering, Radiation; D013056:Spectrophotometry, Ultraviolet
chemical_list: D005465:Fluorocarbon Polymers; D007202:Indicators and Reagents; D008567:Membranes, Artificial; C040402:perfluorosulfonic acid; D007501:Iron; D005947:Glucose; D002118:Calcium