Biomimetic nanostructures for the silicone-biosystem interface: tuning oxygen-plasma treatments of polydimethylsiloxane

Bekim Osmani; Gabriela Gerganova; Bert Müller

doi:10.1515/ejnm-2017-0002

Artikel

Biomimetic nanostructures for the silicone-biosystem interface: tuning oxygen-plasma treatments of polydimethylsiloxane

Bekim Osmani
Bekim Osmani is a PhD student at the Biomaterials Science Center at the University of Basel. He did his BSc in Mechanical Engineering and his MSc in Biomedical Engineering and Robotics at the Swiss Federal Institute of Technology in Zurich (ETHZ) in 2002. After several years of experience in academia and industry, he is currently working toward his PhD degree in nanosciences. His research interests include molecular beam deposition and electrospraying of nanometer thin elastomer films, atomic force microscopy, nanoindentation techniques and mechanical properties of nanometer thin film, polymeric implants and biomedical applications for low-voltage dielectric elastomer actuators.
, Gabriela Gerganova
Gabriela Gerganova, 22 years old, is an integrated master’s student of pharmacology at University of Glasgow. She performs her placement year at the Biomaterials Science Centre under the direction of Prof. Bert Müller. Her research focus is on the formulation, characterization and safety of liposome-based nanocontainers for targeted drug delivery. During her internship, she has expanded her practical skills in biomedical engineering with the help of on-site laboratory facilities.
und Bert Müller
Bert Müller received a diploma in mechanical engineering, Berlin 1982, followed by MSc degrees in Physics and English both from the Dresden University of Technology in 1989. In 1994, he obtained a PhD in experimental physics from the University of Hannover, Germany. For his achievements, he was granted with the Morton M. Traum Award of the American Vacuum Society in 1994. From 1994 to 2001, he worked as a researcher at the Paderborn University, Germany, as Feodor Lynen Fellow and research associate at the EPF Lausanne, Switzerland and as team leader at the Physics Department, Materials Department and Department of Information Technology and Electrical Engineering at ETH Zurich, Switzerland. He became a faculty member of the Physics Department at ETH Zurich in April 2001. After his election as Thomas Straumann-Chair for Materials Science in Medicine at the University of Basel, Switzerland and his appointment at the Surgery Department of the University Hospital Basel in September 2006, he founded the Biomaterials Science Center in March 2007. Currently, this center hosts more than 20 researchers dealing with nanotechnology-based artificial muscles for incontinence treatment, smart nanocontainers to treat cardiovascular diseases, high-resolution X-ray imaging to visualize the human body down to the molecular level, computational sciences of tissues in health and disease and other applications of nanosciences in medicine. The mission of the research team can be summarized by using physical principles for human health. Professor Müller teaches physics and materials science at the ETH Zurich and the University of Basel and currently supervises doctoral students from medicine, dentistry, physics, nanosciences and biomedical engineering. He was elected as Fellow of SPIE in 2014 and as an active member of the European Academy of Sciences and Arts in 2015.

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Aus der Zeitschrift European Journal of Nanomedicine Band 9 Heft 2

Abstract

Polydimethylsiloxanes (PDMS) have drawn attention because of their applicability in medical implants, soft robotics and microfluidic devices. This article examines the formation of dedicated nanostructures on liquid submicrometer PDMS films when exposed to oxygen-plasma treatment. We show that by using a vinyl-terminated PDMS prepolymer with a molecular weight of 800 g/mol, one can bypass the need of solvent, copolymer, or catalyst to fabricate wrinkled films. The amplitude and periodicity of the wrinkles is tuned varying the thickness of the PDMS film between 150 and 600 nm. The duration of the plasma treatment and the oxygen pressure determine the surface morphology. The amplitude was found between 30 and 300 nm with periodicities ranging from 500 to 2800 nm. Atomic force microscopy was used to measure film thickness, amplitude and wrinkle periodicity. The hydrophobic recovery of the nanostructured PDMS surface, as assessed by dynamic contact angle measurements, scales with nanostructure’s fineness, associated with an improved biocompatibility. The mechanical properties were extracted out of 10,000 nanoindentations on 50×50-μm² spots. The mechanical mapping with sub-micrometer resolution reveals elastic properties according to the film morphology. Finally, we tailored the mechanical properties of a 590±120-nm-thin silicone film to the elastic modulus of several MPa, as required for dielectric elastomer actuators, to be used as artificial muscles for incontinence treatments.

Keywords: dielectric elastomer actuators; dynamic contact angle measurements on PDMS; local mechanical properties of thin polymer films; nanometer-thin polymer films; oxygen-plasma-tuned wrinkles

About the authors

Bekim Osmani

Bekim Osmani is a PhD student at the Biomaterials Science Center at the University of Basel. He did his BSc in Mechanical Engineering and his MSc in Biomedical Engineering and Robotics at the Swiss Federal Institute of Technology in Zurich (ETHZ) in 2002. After several years of experience in academia and industry, he is currently working toward his PhD degree in nanosciences. His research interests include molecular beam deposition and electrospraying of nanometer thin elastomer films, atomic force microscopy, nanoindentation techniques and mechanical properties of nanometer thin film, polymeric implants and biomedical applications for low-voltage dielectric elastomer actuators.

Gabriela Gerganova

Gabriela Gerganova, 22 years old, is an integrated master’s student of pharmacology at University of Glasgow. She performs her placement year at the Biomaterials Science Centre under the direction of Prof. Bert Müller. Her research focus is on the formulation, characterization and safety of liposome-based nanocontainers for targeted drug delivery. During her internship, she has expanded her practical skills in biomedical engineering with the help of on-site laboratory facilities.

Bert Müller

Bert Müller received a diploma in mechanical engineering, Berlin 1982, followed by MSc degrees in Physics and English both from the Dresden University of Technology in 1989. In 1994, he obtained a PhD in experimental physics from the University of Hannover, Germany. For his achievements, he was granted with the Morton M. Traum Award of the American Vacuum Society in 1994. From 1994 to 2001, he worked as a researcher at the Paderborn University, Germany, as Feodor Lynen Fellow and research associate at the EPF Lausanne, Switzerland and as team leader at the Physics Department, Materials Department and Department of Information Technology and Electrical Engineering at ETH Zurich, Switzerland. He became a faculty member of the Physics Department at ETH Zurich in April 2001. After his election as Thomas Straumann-Chair for Materials Science in Medicine at the University of Basel, Switzerland and his appointment at the Surgery Department of the University Hospital Basel in September 2006, he founded the Biomaterials Science Center in March 2007. Currently, this center hosts more than 20 researchers dealing with nanotechnology-based artificial muscles for incontinence treatment, smart nanocontainers to treat cardiovascular diseases, high-resolution X-ray imaging to visualize the human body down to the molecular level, computational sciences of tissues in health and disease and other applications of nanosciences in medicine. The mission of the research team can be summarized by using physical principles for human health. Professor Müller teaches physics and materials science at the ETH Zurich and the University of Basel and currently supervises doctoral students from medicine, dentistry, physics, nanosciences and biomedical engineering. He was elected as Fellow of SPIE in 2014 and as an active member of the European Academy of Sciences and Arts in 2015.

Acknowledgments

The financial support of the nano-tera.ch initiative (grant/award no. “SmartSphincter RTD2013”), project SmartSphincter, as well as the Swiss Nanoscience Institute (SNI) for the financial contribution to the AFM is gratefully acknowledged. The authors also thank Dr. Thomas Pfohl and Dr. Tino Töpper for the discussion of the results presented.

Conflict of interest statement: Authors state no conflict of interest. All authors have read the journal’s publication ethics and publication malpractice statement available at the journal’s website and hereby confirm that they comply with all its parts applicable to the present scientific work.

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Received: 2017-2-2

Accepted: 2017-3-2

Published Online: 2017-4-1

Published in Print: 2017-4-1

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Artikel in diesem Heft

https://doi.org/10.1515/ejnm-2017-0002

Schlagwörter für diesen Artikel

dielectric elastomer actuators; dynamic contact angle measurements on PDMS; local mechanical properties of thin polymer films; nanometer-thin polymer films; oxygen-plasma-tuned wrinkles