title: A Simple Approach for Molecular Controlled Release based on Atomic Layer Deposition Hybridized Organic-Inorganic Layers.
abstract: On-demand release of bioactive substances with high spatial and temporal control offers ground-breaking possibilities in the field of life sciences. However, available strategies for developing such release systems lack the possibility of combining efficient control over release with adequate storage capability in a reasonably compact system. In this study we present a new approach to target this deficiency by the introduction of a hybrid material. This organic-inorganic material was fabricated by atomic layer deposition of ZnO into thin films of polyethylene glycol, forming the carrier matrix for the substance to be released. Sub-surface growth mechanisms during this process converted the liquid polymer into a solid, yet water-soluble, phase. This layer permits extended storage for various substances within a single film of only a few micrometers in thickness, and hence demands minimal space and complexity. Improved control over release of the model substance Fluorescein was achieved by coating the hybrid material with a conducting polymer film. Single dosage and repetitive dispensing from this system was demonstrated. Release was controlled by applying a bias potential of ± 0.5 V to the polymer film enabling or respectively suppressing the expulsion of the model drug. In vitro tests showed excellent biocompatibility of the presented system.
authors.affiliation: Freiburg Institute for Advanced Studies (FRIAS), Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany.|Laboratory for Biomedical Microtechnology, Department of Microsystems Engineering (IMTEK), University of Freiburg, 79110 Freiburg, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Boehler
authors.affiliation: Laboratory for Nanotechnology, Department of Microsystems Engineering (IMTEK), University of Freiburg, 79110 Freiburg, Germany.
authors.forename: Firat
authors.initials: F
authors.lastname: Güder
authors.affiliation: Laboratory for Nanotechnology, Department of Microsystems Engineering (IMTEK), University of Freiburg, 79110 Freiburg, Germany.
authors.forename: Umut M
authors.initials: UM
authors.lastname: Kücükbayrak
authors.affiliation: Laboratory for Nanotechnology, Department of Microsystems Engineering (IMTEK), University of Freiburg, 79110 Freiburg, Germany.
authors.forename: Margit
authors.initials: M
authors.lastname: Zacharias
authors.affiliation: Freiburg Institute for Advanced Studies (FRIAS), Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany.|Laboratory for Biomedical Microtechnology, Department of Microsystems Engineering (IMTEK), University of Freiburg, 79110 Freiburg, Germany.
authors.forename: Maria
authors.initials: M
authors.lastname: Asplund