Repetitive on-demand drug release from polymeric matrices containing a macroscopic spherical iron core.

A system for multiple on-demand drug release has been prepared that can be activated with an alternating magnetic field as external trigger. The core/shell samples have been developed based on a macroscopic spherical iron core coated with a thermoresponsive polymer, poly(styrene-stat-butyl methacrylate), containing ibuprofen as a model drug. During exposure of the samples to the magnetic field (ON state), the release rate of ibuprofen is significantly increased, up to 35 times the release rate without the magnetic field (OFF state). Using one sample or two samples in line with the magnetic field does not influence the ON/OFF ratio of the system, showing the possibility of using multiple samples to increase and tune the drug dose. Increasing the concentration of ibuprofen in the polymer layer is shown to increase the release rate in both the ON and OFF states. Increasing the size of the iron core and, consequently, decreasing the polymer thickness, was found to only increase the release rate during exposure resulting in higher ON/OFF ratios. The developed on demand drug delivery systems represents a promising development towards on demand drug delivery implants.

REFLECTIONS ON CAREER GOALS: During my chemical engineering studies, it was only during my master thesis work that I decided to continue with PhD research as I really enjoyed doing original research. When coming to the end of my PhD research under supervision of Prof. Ulrich S. Schubert, I developed the ambition to pursue an academic career. Fortunately, I got the opportunity to stay with Prof. Schubert as project leader for the Dutch Polymer Institute (DPI). Within this position, I supervised ten researchers and was able to start developing my independent research lines. Despite that I now advise students to not stay in the same laboratory, this first position allowed me to gain some initial independence and to publish a large number of papers that has been a great benefit in my further career. After two and a half years I needed a new challenge that I found by taking up a part-time position at a start-up company in Eindhoven, Dolphys Medical BV, while I also continued as part-time group leader for the DPI. As senior product developer, I was in charge of the research and learned to focus on the application rather than scientific curiosity. This experience made me realize that I prefer the freedom to do academic blue sky research and decided to fully go for an academic position. After personal discussions with some prominent professors in the Netherlands, I applied for a postdoc fellowship in the Netherlands with Prof. Roeland Nolte as well as a Humboldt fellowship in Germany with Prof. Martin Möller, which I both got. As a result, I went one year 'abroad' to Aachen and returned to Nijmegen where I intended to start my independent career. However, another opportunity came along. Via my personal network I was informed that I would make a good chance if I applied for a new professor scheme in Ghent. So I applied and the rest is history. Picture of the Supramolecular Chemistry Group (2017).