Laura Finck (Braunschweig, DE), Valentin Hagemann (Hannover, DE), Felix Künzel (Braunschweig, DE), Prof. Dr. Peter Behrens (Hannover, DE), Prof. Dr. Henning Menzel (Braunschweig, DE)
Abstract text (incl. figure legends and references)
Introduction: In the further development of implant materials, it is of utmost interest to make the implants safer. Not only the prevention of infections but also easy removal should be considered. The aim is to develop implant coatings that facilitate the removal of an implant by a trigger. Hydrogels are suitable for this application since their structure and mechanical properties are very similar to human tissue. It is known in the literature that nanoparticles can glue synthetic hydrogels with other hydrogels or soft tissue, and this gluing can be reversed at higher temperatures. The use of superparamagnetic core-shell nanoparticles, which allow extremely localized heating, should enable release of adhesion with an alternating magnetic field as external trigger. The superparamagnetic nanoparticles can generate heat through magnetic hyperthermia to separate the bonded materials and facilitate explantation without the damaging surrounding tissue.
Objective: An ultrathin hydrogel shall be covalently bonded to the implant surface for the coating. For this purpose, a copolymer was prepared that can bind to the implant surface via a phosphonate group. Furthermore, a photo-crosslinkable group like arylazide and hydrophilic groups to form a hydrogel were incorporated. The coatings were characterized via in-situ ellipsometry measurements.
Methods: An Optrel Multiskop Ellipsometer was modified with cuvettes as light guides to perform in-situ measurements. Scanning electron micrographs were obtained using a Helios G4 CX Dual Beam.
Results: Layer thicknesses of between 40 and 140 nm in the dry state can be adjusted via the concentration of the spin-coating solution. The coatings swell in water to about twice their thickness. The immobilization of different nanoparticles can be confirmed by SEM.
Conclusion: The production of ultrathin polymer coatings was demonstrated using ellipsometry. These coatings can swell in water and immobilize nanoparticles on their surface.