Bioactivation of surfaces by ion implantation
Professor Marcela Bilek
Applied and Plasma Physics, University of Sydney
The ability to strongly attach biomolecules to surfaces whilst retaining their biological activity underpins a host of biotechnologies, such as biosensors and diagnostic microarrays for early disease detection. Recent work has revealed that radicals embedded in carbon rich surface layers by energetic ion bombardment can covalently immobilize bioactive proteins [Proc. Nat. Acad. Sci 108(35) pp.14405-14410 (2011)]. This new approach delivers the strength and stability of covalent coupling without the need for multi-step wet chemistry. Immobilization occurs in a single step directly from solution and the hydrophilic nature of the surface ensures that the bioactive 3D shapes of the protein molecules are not disturbed.
Such energetic ion treatments can be applied to any underlying material making it possible to achieve covalent biomolecule immobilization whilst maintaining the physical properties (including mechanical and electrical) of an underlying material. This opens up the possibility of new applications such as integrated microelectronic or photonic biosensing devices, continuous flow reactors for enzymatic chemical, textile, food or biofuels processing and implantable biomaterials that interact with their host via an interfacial layer of active biomolecules to direct a desired cellular response to the implant.
This presentation will describe the plasma-based approaches for creating suitable buried radicals through energetic ion impacts that we have developed as part of a multi-disciplinary research team. A kinetic theory model of the immobilization process through reactions with long-lived, mobile, surface-embedded radicals and supporting experimental data will be presented. The roles of surface chemistry and microstructure of the treated layer in simultaneously preventing radical annihilation whilst allowing sufficient radical mobility will be discussed. Preliminary applications of this technology to direct cell growth, create sensors and diagnostic arrays, and to engineer bioactive surfaces for implantable biodevices will be reviewed.
Professor Marcela Bilek holds a PhD from the University of Cambridge, UK, a BSc from the University of Sydney and an MBA from the Rochester Institute of Technology, USA. Prior to her present appointment as Professor of Applied Physics at the University of Sydney (since 2000), she worked as a visiting Scientist at the Lawrence Berkeley National Laboratory in Berkeley, USA, held a visiting Professorship at the Technische Universitat Hamburg-Harburg in Germany and a Research Fellowship at Emmanuel College, University of Cambridge, UK.
Marcela has authored and co-authored over 220 refereed journal articles, 1 book, 4 book chapters and filed 6 patents. She has received a number of honours for her work including the Malcolm McIntosh Prize for Physical Scientist of the Year in 2002, an ARC Federation Fellowship and an MIT TR100 Young Innovator award in 2003, the Australian Academy of Science Pawsey Medal in 2004 an Australian Innovation Challenge Award in 2011 and an ARC Future Fellowship in 2012. Last year she was elected to the Fellowship of the American Physical Society “for outstanding contributions to the physics of plasma processing, resulting in plasma sources, processes and materials with applications to industries ranging from information technology to biomedicine”.