Biomimetic Coating on Polymeric Implant
Surfaces -The Need of a Quality Standard
Dietmar Schaffarczyk1*, Andreas Schwitalla2 and Stefan Leonhardt3
1Lead Auditor for Medical Devices, stimOS GmbH, Germany
2Department of Prosthodontics, Charité, University of Berlin Germany
3Kumovis GmbH, Germany
Submission: July 20, 2020;Published: July 27, 2020
*Corresponding author: Dietmar Schaffarczyk, Lead Auditor for Medical Devices, stimOS GmbH, Germany
How to cite this article:Schaffarczyk D, Schwitalla A, Leonhardt S. Biomimetic Coating on Polymeric Implant Surfaces -The Need of a Quality Standard.
Academ J Polym Sci. 2020; 4(2): 555635. DOI: 10.19080/AJOP.2020.04.555635
Polyetheretherketone (PEEK) is a promising implant material because of its excellent mechanical characteristics. Although this polymer is a standard material in spinal applications, PEEK has the disadvantage by its relative bio-inertness . This is the reason why coating technologies have built an impressive catalogue of success in many different applications: With a growing need for coating technologies to functionalize the surface of polymeric medical devices, the medical industry saw enormous growth in coating application onto medical devices. Various types of coatings technologies, coating materials and substances are available to date: Spanning from plasma spray coating technologies to dip coating techniques, from titanium or hydroxyapatite, all which
enhance cell attachment onto orthopedic implants. But there are also various risks associated with the materials and methods mentioned above: amongst others, delamination, wear debris, abrasion, particle migration, infection or corrosion. Performing an exhaustive literature research and during different test set-ups simulating the predictable way of use of coated polymeric
implants the authors have analyzed and evaluated the most common used and regulatory cleared coating materials and technologies in medical-device-applications. This paper is meant to give insights into the safety and performance characteristics of the most commonly used coating materials and methods onto polymeric implant surfaces.
Almost all commonly used coating materials and technologies
suffer from debris, delimitation and abrasion. Coating technologies
incorporating titanium additionally are suspected to corrode,
particularly in acidic environments and to cause inflammatory
reactions [2-5]. The table below summarizes the different
disadvantages and drawbacks of commonly known and regulatory
cleared coating technologies. The results presented here have
been analyzed and evaluated by Pubmed literature searches and/
or during simulated use tests performed by the authors and/or
affiliated companies and institutes (Tables 1 & 2) (Figures 1-3).
In vitro studies of the above mentioned coating technologies
have shown encouraging results regarding osseointegration. But
mechanical tests have shown the disadvantages of plasma sprayed
coated surfaces, whereas coatings that incorporate titanium may
corrode and result in inflammatory reactions. Coatings with a
layer-thickness in a 3-digit-micrometer range may influence
negatively the engineered topography of 3D-printed implants.
With all these different materials and substrates used in coating
applications as also due to the various coating technologies, one
can get easily lost in a jungle of information: On the one hand side
there are some standardized test methods to proof the mechanical
stability of the coating layers on the implants surface, on the other
hand these methods cannot be used to characterize the mechanical
behavior of the various technologies. For biocompatibility testing
different set-ups of in-vitro cell test methods and in-vivo animal
models can be found in literature. The different coating materials
can easily lead to a higher risk-classification of the coated implant.
Different and unstructured testing methods and untransparent
information may lead to wrong decisions, resulting in reduced
safety and performance of polymer-implants. The authors suggest
to define and establish an evaluation matrix for different surface
functionalization technologies and to introduce a quality standard
for coating technologies with transparent safety and performance
parameters. To introduce such a quality standard will be subject
of further research work, guidelines and publications.