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The neural tissue around SU-8 implants: A quantitative in vivo biocompatibility study
Gergely Márton1, Estilla Zsófia Tóth2, Lucia Wittner3
1Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Magyar tudósok körútja 2, Budapest 1117, Hungary; Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Práter utca 50/A, Budapest 1083, Hungary; Doctoral School on Materials Sciences and Technologies, Óbuda University, Bécsi út 96/b, Budapest 1034, Hungary.
SU-8 neural sensors show high biocompatibility in rat brains, with minimal neuronal loss and a thin glial scar. These findings support SU-8
Area of Science:
- Biomaterials Science
- Neuroscience
- Medical Devices
Background:
- SU-8 material is increasingly used for neural sensors.
- Quantitative biocompatibility data in the central nervous system is limited.
Purpose of the Study:
- To quantitatively assess SU-8 biocompatibility in the rat neocortex.
- To analyze neuronal preservation and astrogliosis around SU-8 implants.
Main Methods:
- Immunohistochemistry to quantify neuronal density and astrogliosis.
- Electron microscopy to examine synaptic contacts and glial scar thickness.
- Implantation of SU-8 devices in rat neocortex with 2-month survival.
Main Results:
- Neuronal density decreased significantly only within 20 μm of the implant.
- Synaptic contact density recovered to control levels at 24 μm.
- A thin glial scar (5-10 μm) formed, with limited glial processes in the neuropil.
- Astrogliosis extended up to ~500 μm, but neuronal survival was high overall.
Conclusions:
- SU-8 exhibits high biocompatibility in the central nervous system.
- Neuronal damage is localized to a very small area around the implant.
- SU-8 based neural devices are promising for future applications.
