We developed a fabrication method of the softest brain implant to date using a silicone elastomer, Ecoflex, with Young’s modulus of 20 kPa. The 300 µm wide x 200 µm thick x 3 mm long implants were fabricated by vacuum-assisted molding (Hernández-Castro, Li, Meunier, Juncker and Veres, Lab Chip, 2017, 17, 1960–1969). The soft brain implants were encased inside a micro-molded dissolvable sugar shuttles for accurate implantation. Immunohistochemistry showed that the soft brain implants elicited significantly lower brain foreign body response compared to silicon and PDMS implants. A lower brain foreign response could lead to higher quality recordings and long-term implant reliability.
(A) SU-8 master mold for vacuum assisted molding. (B) Insertion of brain implant encased in a dissolvable sugar shuttle into rat brain showing the insertion of the sugar shuttle, and closing of the brain tissue upon dissolution of the sugar.
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