title: Visual H2sensor for monitoring biodegradation of magnesium implants in vivo.
abstract: A visual sensor for H2was used to transdermally monitor H2that originated from biodegrading magnesium (Mg) alloys implanted subcutaneously in mice. The visual sensor consisted of a thin film of H2-sensitive material (MoO3and Pd catalyst) coated on a flexible plastic sheet that was pressed against the mouse skin directly above the implant. Although the H2levels permeating through the skin during the degradation process were very low, the sensor changed color to give a three dimensional (3D) visualization of H2permeation. The correlation between the visual sensor response and measurements made with an electrochemical H2microsensor on several magnesium alloys demonstrates that the visual sensor has the capability to monitor in real-time the dissolution rate of implants in vivo. This detection method is noninvasive, easy to implement, effective and potentially low cost compared to electrochemical detection.
  
  
  
  Biodegradable Mg implants offer advantages over permanent implants such as stainless steel that are used for broken bone repair. Mg alloys gradually dissolve, avoiding the need for removal by a later surgery if complications arise. Here we report a visual H2sensor that can be used in the research laboratory to monitor the corrosion process in vivo during animal testing of different Mg alloys. The sensor consists of a plastic sheet with a thin coating that changes color in the presence of H2gas. The sensor is easily used by taping it on the skin over the Mg implant. The color change gives a map of the H2level permeating from the degrading Mg through the skin above it. This low cost, simple method of monitoring the dissolution of biodegradable implants would greatly facilitate the development of the biodegradable materials, especially in animal studies where in vivo biodegradation is tested.
authors: Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221, USA.
authors: Daoli
authors: D
authors: Zhao
authors: Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221, USA.
authors: Tingting
authors: T
authors: Wang
authors: Element One, Inc., Boulder, CO 80301, USA.
authors: William
authors: W
authors: Hoagland
authors: Element One, Inc., Boulder, CO 80301, USA.
authors: David
authors: D
authors: Benson
authors: Department of Internal Medicine, University of Cincinnati, Cincinnati, OH 45267, USA.
authors: Zhongyun
authors: Z
authors: Dong
authors: Department of Internal Medicine, University of Cincinnati, Cincinnati, OH 45267, USA.
authors: Shuna
authors: S
authors: Chen
authors: Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261, USA.
authors: Da-Tren
authors: DT
authors: Chou
authors: Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261, USA.
authors: Daeho
authors: D
authors: Hong
authors: Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261, USA.
authors: Jingyao
authors: J
authors: Wu
authors: Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261, USA; Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA; Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA 15261, USA.
authors: Prashant N
authors: PN
authors: Kumta
authors: Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221, USA. Electronic address: William.Heineman@uc.edu.
authors: William R
authors: WR
authors: Heineman
mesh_terms: D020341:Absorbable Implants; D000497:Alloys / Q000737:chemistry; D000818:Animals; D003116:Color; D055664:Electrochemical Techniques / Q000295:instrumentation*; D005260:Female; D006859:Hydrogen / Q000032:analysis*; D008274:Magnesium / Q000737:chemistry*; D008819:Mice, Nude
chemical_list: D000497:Alloys; D006859:Hydrogen; D008274:Magnesium
keywords: Biodegradable implants; Hydrogen; Magnesium alloys; Visual sensor