Evaluation of negative photo-patternable PDMS for the encapsulation of neural electrodes

Delivopoulos, E. ORCID: https://orcid.org/0000-0001-6156-1133, Minev, I. R. and Lacour, S. P. (2011) Evaluation of negative photo-patternable PDMS for the encapsulation of neural electrodes. In: 2011 5th International IEEE/EMBS Conference on Neural Engineering. IEEE, pp. 490-494. doi: 10.1109/NER.2011.5910593

Abstract/Summary

This communication examines the suitability of a photo-patternable polydimethylsiloxane (PP-PDMS) elastomer as an insulating material for implantable microelectrodes. PP-PDMS is produced by mixing a photoinitiator (2-hydroxy-2-methylpropiophenone) with the PDMS base and curing agent. Subsequent exposure to UV radiation and development of the elastomeric “photo-resist” allows for the definition of well-defined openings within the PP-PDMS film. The dielectric constants of PP-PDMS and PDMS are similar (ε ≈ 2.6, f <;1MHz). Gold film microelectrodes patterned on glass or a PDMS substrate are encapsulated with PP-PDMS, while recording sites as small as 104 μm2 can be obtained in the PP-PDMS layer. The cytotoxicity of the PP-PDMS was preliminary tested in vitro by culturing 3T3 fibroblasts in PP-PDMS extracts. No adverse effects were observed in cultures exposed to PP-PDMS films initially leached in isopropanol solvent for 48h.