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Multifunctional Conducting Polymer Coatings for Magnesium Implants

Catt, Kasey (2016) Multifunctional Conducting Polymer Coatings for Magnesium Implants. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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Abstract

Magnesium’s potential to degrade completely in vivo with safe corrosion byproducts make it a promising biomaterial for use in a wide array of implants from orthopedic fixation devices that do not require a removal surgery to peripheral nerve guides that degrade away after regeneration. However, a few issues need to be addressed before widespread clinical use can be realized. Firstly, Mg often degrades too rapidly in vivo. Rapid degradation can result in the mechanical instability and gas bubbles that may separate the implant from the tissue. Secondly, Mg implants lack the ability to combat potential infection and the inflammatory foreign body response. Lastly, Mg alone lacks a versatile functionalization method to incorporate tissue specific cues that better guide tissue growth and regeneration. To overcome these issues, conducting polymer based coatings with a combination of functionalities in corrosion control, drug release, and biofunctionalization are investigated in this thesis.
A composite coating of conducting polymer poly 3,4-ethylene dioxythiophene (PEDOT) doped with Graphene Oxide (GO) has been developed for improving Mg implant performance for applications such as orthopedic fixation, stents, and peripheral nerve regeneration. The PEDOT/GO coating decreased Mg corrosion throughout 22days of immersion in a phosphate buffered solution. Corrosion protection is attributed to an initial passive barrier followed by electrochemical coupling of the coating with the Mg to from a more protective Mg phosphate layer. Additionally, anti-inflammatory drug Dexamethasone was incorporated into the PEDOT/GO film and it was shown that Mg corrosion current could drive drug release. Lastly, the carboxylic acid groups of the GO sheets exposed at the surface of the PEDOT/GO coating were used to immobilize multiple bioactive molecules. Specifically, immobilized poly ethylene glycol (PEG) prevented both bacterial and fibroblast attachment, while nerve growth factor (NGF) attachment increased neurite sprouting from PC12 cells. These results suggest that the PEDOT/GO coating has the potential to be a versatile coating that can provide corrosion protection and add biologically relevant cues to the Mg implant


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Details

Item Type: University of Pittsburgh ETD
Status: Unpublished
Creators/Authors:
CreatorsEmailPitt UsernameORCID
Catt, Kaseykac200@pitt.eduKAC200
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairCui, Tracyxic11@pitt.edu
Committee MemberKumta, Prashantpkumta@pitt.edu
Committee MemberMarra, Kaceymarrak@upmc.edu
Committee MemberYun, Yeohungyyun@ncat.edu
Date: 16 September 2016
Date Type: Publication
Defense Date: 23 June 2016
Approval Date: 16 September 2016
Submission Date: 27 July 2016
Access Restriction: 5 year -- Restrict access to University of Pittsburgh for a period of 5 years.
Number of Pages: 173
Institution: University of Pittsburgh
Schools and Programs: Swanson School of Engineering > Bioengineering
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: Magnesium, Corrosion, Conducting Polymer
Date Deposited: 16 Sep 2017 05:00
Last Modified: 16 Sep 2017 05:00
URI: http://d-scholarship.pitt.edu/id/eprint/28976

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