Background
Implantable biomedical devices such as neural probes, biosensors and microstimulators enable chronic monitoring and actuation of physiological and biological functions. However, the tissue damage induced during surgical implantation can lead to chronic inflammation owing to the mechanical mismatch between commonly used stiff substrate materials such as silicon and soft biological tissue. Surface chemistry has also been shown to drive molecular and tissue reactions to implant materials by promoting or reducing protein adsorption and cell interactions. SU-8 is a photosensitive epoxy-based polymer that is widely used in MEMS technologies as substrate and structural element. Using photolithography, both thin (< 5 ?m) and thick (< 100 ?m) films can be patterned with microscale features. SU-8 is chemically tunable via surface functionalization including plasma treatment and wet chemical processes. We fabricate sensing interfaces with SU-8 as a compliant substrate material for the electrochemical detection of neurotransmitters and for electrophysiological recording studies in rodents. We aim at developing highly biocompatible implants to limit the foreign-body response, prevent device failure and guarantee long-term in vivo operation.
Project
This master project entails the study of how SU-8-based implants with various surface chemistry elicit local tissue response. The work will be conducted in collaboration with another student who will fabricate the implants and fine-tune their surface chemistry.
Methods
The student will conduct cell culture experiments including immunohistochemistry. In vivo implantation of SU-8 neural probes will allow the student to analyze the in vivo biocompatibility of the implants in brain tissue.
About the student
We are looking for a driven and autonomous student with a background in biology and/or immunology. Prior experience with immunohistochemistry and cell cultures is an advantage. Basic knowledge in material chemistry is a plus.
About us
During this master project, the student will be involved in a highly interdisciplinary research environment bridging a sleep and cognitive development lab at the Norwegian Center for Molecular Biosciences and Medicine (boccaralab), the Center for Material Science and Nanotechnology (SMN) and the Electronics section at the Department of Physics (Fys).
References
- Chen, Z., & Lee, J.-B. (2021). Biocompatibility of SU-8 and Its Biomedical Device Applications. Micromachines, 12(7), Article 7. https://doi.org/10.3390/mi12070794
- Lee, H. C., Ejserholm, F., Gaire, J., Currlin, S., Schouenborg, J., Wallman, L., Bengtsson, M., Park, K., & Otto, K. J. (2017). Histological evaluation of flexible neural implants; flexibility limit for reducing the tissue response? Journal of Neural Engineering, 14(3), 036026. https://doi.org/10.1088/1741-2552/aa68f0
- Nemani, K. V., Moodie, K. L., Brennick, J. B., Su, A., & Gimi, B. (2013). In vitro and in vivo evaluation of SU-8 biocompatibility. Materials Science and Engineering: C, 33(7), 4453– 4459. https://doi.org/10.1016/j.msec.2013.07.00
- Huang, S.-H., Lin, S.-P., & Chen, J.-J. J. (2014). In vitro and in vivo characterization of SU-8 flexible neuroprobe: From mechanical properties to electrophysiological recording. Sensors and Actuators A: Physical, 216, 257– 265. https://doi.org/10.1016/j.sna.2014.06.005
- Thevenot, P., Hu, W., & Tang, L. (2008). SURFACE CHEMISTRY INFLUENCE IMPLANT BIOCOMPATIBILITY. Current Topics in Medicinal Chemistry, 8(4), 270–280