Nanostructured surfaces

Effect of plasma activation and thin film deposition on the PEEK polymer surfaces
Przykaza K.1, Woźniak K.1, Ładniak A.1 Jurak M.1 Wiącek A.E.1
1 University of Maria Curie-Skłodowska, Faculty of Chemistry, Department of Interfacial Phenomena, Maria Curie-Skłodowska Square 3, 20-031 Lublin, Poland.
E-mail: przykaza.kacper@poczta.umcs.lublin.pl

Polyetheretherketone (PEEK) is a highly biocompatible polymer widely applied in medicine as a material for the production of bone implants. The great interest in this polymer in orthopedics results from its competitive properties in relation the to previously used metal titanium and platinum alloys materials. The implants made of PEEK do not cause allergies, they generate less mechanical stresses and tolerate different types of sterilization processes as well as surface modification. Moreover, they also guarantee easy post-operative imaging with the X-ray method compared to the metal counterparts. Unfortunately, the great problem associated with the use of PEEK polymer is the limited osseointegration caused by its high chemical passivity [1].
In this experiment the PEEK surface was characterized in terms of changes in its wettability after the physicochemical modifications applying low-temperature air plasma and the Langmuir-Blodgett (LB) layers of the polypeptide (cyclosporine A, CsA) and / or phospholipid (1,2-dipalmitoyl-sn-glycerol) 3-phosphocholine, DPPC) and sterol (cholesterol). The surface was characterized by means of the optical profilometer and additionally, we determined the characteristics of the surface wettability and surface free energy changes based on the theoretical model of interfacial interactions proposed by van Oss and co-authors. [2]. Such modifications can improve PEEK biocompatibility, increase cell adhesion, accelerate wound healing or reduce inflammation in the tissues surrounding the implant. The preparation of polymer coatings with defined polarity and composition is an important step in the development of implant surfaces with the increased biofunctionality.

1.	Chan L., Lei L., Jian-Yong S., Kai-Zhong Y., Wei-Zhong S. Clinical and biomechanical researches of polyetheretherketone (PEEK) rods for semi-rigid lumbar fusion: a systematic review. Neurosurgical Review.-2018-41.-P. 375-389. 
2.	Van Oss C.J., Chaudhury M. K., and Good R. J. Interfacial Lifshitz-van der Waals and polar interactions in macroscopic systems. Chemical Reviews.-1990.-88.-P. 927-941.