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Journal ArticleDOI

PEGylation of platinum bio-electrodes

01 Feb 2013-Electrochemistry Communications (Elsevier)-Vol. 27, pp 54-58
TL;DR: In this article, PEGylation was conducted on platinum bio-electrodes to render the surface protein-resistant, which was investigated using a quartz crystal microbalance-dissipation, electrochemical impedance spectroscopy and cyclic voltammetry.
About: This article is published in Electrochemistry Communications.The article was published on 2013-02-01 and is currently open access. It has received 13 citations till now. The article focuses on the topics: Cyclic voltammetry & PEGylation.

Summary (1 min read)

Jump to: [1. Introduction][3.1 QCM-D] and [4. Conclusions]

1. Introduction

  • The therapeutic efficacy of a chronically implanted neural prosthesis, such as the cochlear implant, is determined by the ability to effectively transfer charge across the electrode-tissue interface.
  • Controlling the protein interactions at the implanted electrode interface is thus becoming an important strategy for the management of adverse tissue responses around the device.
  • In addition to drug delivery, PEG has been intensively explored as biocompatible, anti-fouling coatings for medical implants to improve the in vivo efficacies.
  • Experimental 2.1 Materials mPEG thiols (Mw 5000 Da) were purchased from Jenkem Technology Co., Ltd, China.
  • A three-electrode electrochemical cell was used for all the electrochemical measurements, consisting of a Pt or Pt-PEG working electrode, a platinum mesh auxiliary electrode and an Ag│AgCl (3.0 M NaCl) reference electrode.

3.1 QCM-D

  • QCM-D was employed to monitor the PEGylation process and protein adsorption behavior through changes in resonance frequency (∆ƒ, coupled to layer hydrated mass) and energy dissipation (∆D, coupled IPRI/12120/4.9.12 to layer viscoelasticity).
  • 11,12 By modeling the frequency and dissipation shifts using the viscoelastic Voigt model, the thickness and mass of the hydrated PEG were determined to be 8.0±0.4 nm and 822±46 ng/cm2, respectively.
  • Pt electrode after exposure to BSA or fibrinogen becomes plateau-shaped with a pronounced reduction in the currents, emphasizing a strong blocking effect of the adsorbed proteinaceous layer (Fig. 2C).
  • For cochlear implants, the in-vivo impedance has shown to be governed predominantly by the biological environment surrounding the electrode, such as fibrotic tissue response, and increase up to 6-7 folds after a 12-week implantation.
  • 21,22 The strategy of PEGylation reported here provides some control over the evolution of the electrode-tissue interface by minimizing nonspecific protein adsorption and subsequent foreign body response.

4. Conclusions

  • The immobilized PEG coating is highly hydrated and permeable, with a thickness of ~ 8 nm, and can inhibit ≥ ~92% adsorption of both BSA and fibrinogen.
  • The authors acknowledge the financial support of the HEARing CRC, established and supported under the Australian Government's Cooperative Research Centres Program, and the support of IPRI/12120/4.9.12 the ANFF Facility.
  • The authors acknowledge staffs from ACES, Dr. Carrie Newbold from the HEARing CRC, and Dr. Claudia Tasche, Mr. Freddy Dueck and Dr. Matin Svehla from Cochlear Ltd for technical support.

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Citations
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Journal ArticleDOI
TL;DR: It is shown that coatings of lubricin protein are as effective as, or better than, self-assembled monolayers of polyethylene glycol over a wide range of pH and that this provides a simple, versatile, highly stable, and highly effective method of controlling unwanted adhesion to surfaces.

73 citations

Journal ArticleDOI
TL;DR: In this paper, the authors discuss strategies and concepts used throughout the literature to prevent electrode surface fouling in biosensors and to communicate the nature of the antifouling mechanisms by which they operate.
Abstract: Although there exist numerous established laboratory-based technologies for sample diagnostics and analyte detection, many medical and forensic science applications require point of care based platforms for rapid on-the-spot sample analysis. Electrochemical biosensors provide a promising avenue for such applications due to the portability and functional simplicity of the technology. However, the ability to develop such platforms with the high sensitivity and selectivity required for analysis of low analyte concentrations in complex biological samples remains a paramount issue in the field of biosensing. Nonspecific adsorption, or fouling, at the electrode interface via the innumerable biomolecules present in these sample types (i.e., serum, urine, blood/plasma, and saliva) can drastically obstruct electrochemical performance, increasing background "noise" and diminishing both the electrochemical signal magnitude and specificity of the biosensor. Consequently, this review aims to discuss strategies and concepts used throughout the literature to prevent electrode surface fouling in biosensors and to communicate the nature of the antifouling mechanisms by which they operate. Evaluation of each antifouling strategy is focused primarily on the fabrication method, experimental technique, sample composition, and electrochemical performance of each technology highlighting the overall feasibility of the platform for point of care based diagnostic/detection applications.

69 citations

Journal ArticleDOI
TL;DR: The advent of the cochlear implant is phenomenal because it is the first surgical prosthesis that is capable of restoring one of the senses and the time has come to investigate their collective applications to co chlear implants to restore lost hearing.

30 citations

Journal ArticleDOI
TL;DR: Atomic force microscopy (AFM) normal force measurements provide insight into the architecture of the HA/LUB composite layer and implicate a strong contribution of hydrophobic interactions in the binding of LUB end-domains directly to HA chains.
Abstract: Preventing the unwanted adsorption of proteins and cells at articular cartilage surfaces plays a critical role in maintaining healthy joints and avoiding degenerative diseases such as osteoarthriti...

29 citations

References
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Journal ArticleDOI
TL;DR: How PEGylation can result in drugs that are often more effective and safer, and which show improved patient convenience and compliance are reviewed.
Abstract: Protein and peptide drugs hold great promise as therapeutic agents. However, many are degraded by proteolytic enzymes, can be rapidly cleared by the kidneys, generate neutralizing antibodies and have a short circulating half-life. Pegylation, the process by which polyethylene glycol chains are attached to protein and peptide drugs, can overcome these and other shortcomings. By increasing the molecular mass of proteins and peptides and shielding them from proteolytic enzymes, pegylation improves pharmacokinetics. This article will review how PEGylation can result in drugs that are often more effective and safer, and which show improved patient convenience and compliance.

3,142 citations

Journal ArticleDOI
TL;DR: PEG is the most used polymer and also the gold standard for stealth polymers in the emerging field of polymer-based drug delivery and alternative polymers will be evaluated.
Abstract: Poly(ethylene glycol) (PEG) is the most used polymer and also the gold standard for stealth polymers in the emerging field of polymer-based drug delivery. The properties that account for the overwhelming use of PEG in biomedical applications are outlined in this Review. The first approved PEGylated products have already been on the market for 20 years. A vast amount of clinical experience has since been gained with this polymer--not only benefits, but possible side effects and complications have also been found. The areas that might need consideration and more intensive and careful examination can be divided into the following categories: hypersensitivity, unexpected changes in pharmacokinetic behavior, toxic side products, and an antagonism arising from the easy degradation of the polymer under mechanical stress as a result of its ether structure and its non-biodegradability, as well as the resulting possible accumulation in the body. These possible side effects will be discussed in this Review and alternative polymers will be evaluated.

2,815 citations

Journal ArticleDOI
15 Aug 2001-Blood
TL;DR: The question of how fibrinogen is converted to a proinflammatory state when adsorbed to biomaterial surfaces is investigated and may help explain both the inflammation caused by many types of implanted biomaterials and that which occurs naturally following thrombotic events.

421 citations

Journal ArticleDOI
TL;DR: In this article, a poly(oxyethylene) (POE) chain with 15 ethylene oxide (EO) units have been performed in an aqueous solution for 2 ns at 300 K and for 1 ns at 373 K, a cloud point for POE.
Abstract: Molecular dynamics simulations of a poly(oxyethylene) (POE) chain with 15 ethylene oxide (EO) units have been performed in an aqueous solution for 2 ns at 300 K and for 1 ns at 373 K, a cloud point for POE. The conformation and the hydration structure of POE and the structure and the dynamics of water molecules in the vicinity of POE were examined. The conformation of POE was transformed from a collapsed chain in the gas phase to a helix in water which was maintained for 2 ns. After a simulated annealing at 1000 K, POE still showed a preference for a helix. An extended network of POE−water and water−water hydrogen bonds was found throughout inside the helix, stabilizing the helix backbone. The same helical conformation was maintained even at 373 K. The pair distribution functions for water oxygen atoms near POE indicated significantly enhanced water structures in the hydrophilic region of POE, and to a lesser extent in the hydrophobic region, at both 300 and 373 K. Considerably reduced translational movem...

338 citations

Journal ArticleDOI
TL;DR: This review focuses on recent advances in increased implant efficacy through selective surface modifications and examines the biocompatible and bioactive device surface modification advances from the past five years that hold the potential of increased in vivo effectiveness.
Abstract: Generally, medical implants, regardless of their construction materials, will become coated in a layer of non-specific proteins mere seconds after implantation. This adsorbed layer activates an irrevocable host defense mechanism, known as the foreign body reaction, which ultimately results in the production of a fibrous avascular capsule that isolates the device from its target tissues, clogs the pores of membranes and sensors, and prevents drug release from a delivery vehicle. Many devices eventually fail because of their inability to effectively communicate with the surrounding tissues. It is becoming apparent that sub-cellular interactions at the biological-material interface have macroscopic outcomes. The success of the next generation of implants depends on overcoming limitations in biological communication by selective modification of device surfaces. This review focuses on recent advances in increased implant efficacy through selective surface modifications. Several approaches co-opt solutions found in the natural world to create a surface that mimics the properties of the cell membrane, thereby imparting a pseudo-biological character to synthetic materials. We begin with a short description of the foreign body reaction and then examine the biocompatible and bioactive device surface modification advances from the past five years that hold the potential of increased in vivo effectiveness.

223 citations

Frequently Asked Questions (2)
Q1. What have the authors contributed in "Pegylation of platinum bio-electrodes" ?

In this study, PEGylation was conducted on platinum bio-electrodes to render the surface protein-resistant. The PEGylated electrode was investigated using a quartz crystal microbalance-dissipation, electrochemical impedance spectroscopy and cyclic voltammetiy. 

Optimisation of the coating properties in terms of the invivo electrode performance is required in the future, and the knowledge gained will provide a basis to facilitate the ongoing development of cochlear implants, as well as other types of neural prostheses for improved electro-neural interfacing.