Extended Data Fig. 1: Monolithically integrated tissue-level flexible mesh electronics.
From: Tracking neural activity from the same cells during the entire adult life of mice
Schematics showing the stepwise fabrication. a, A Ni sacrificial layer (grey) was defined by photolithography and deposited through thermal evaporation on the Si/SiO2 wafer (purple). b, SU-8 2000.5 bottom passivation layer (red) was defined by photolithography. c, Cr/Au interconnects and Pt microelectrodes (yellow) were sequentially defined by photolithography and deposited through electron beam (e-beam) evaporation on the top of the SU-8 passivation layer. d, SU-8 2000.5 top passivation was defined by photolithography (red). e, SU-8 2025 anchor was defined by photolithography (cyan). f, Dextran sacrificial layer (pink) was spin coated. g, SU-8 2025 shuttle was defined by photolithography (navy). h-m, Optical images illustrating each step of the fabrication corresponding with (b-g), respectively. n, Schematics showing the cross-section of the monolithically integrated mesh electronics at the red and black dashed boxes highlighted regions in (m), respectively. o-q, Contact profilometer measurements of the open mesh structure in (j, red dashed line), anchor structure in (k, cyan dashed line), and shuttle structure in (m, blue dashed line). r, Statistical summary of the thickness of the open mesh, anchor, and shuttle layer structures (n = 5 independent mesh electronics. Data are presented as mean ± s.d.). s-x, Schematics illustrating the preparation and releasing of mesh electronics for implantation. Color scheme is the same as in a-g. s, Side view of as-made mesh electronics. t, Flat flexible cable (FFC) was bonded to I/O pads of mesh electronics. u, The implanted part of the device was immersed in the Ni etchant to release the mesh electronics from the substrate. During this process, the dextran layer underneath the mesh electronics is also dissolved. The anchor and I/O pads maintain the overall geometry and intact structure of mesh electronics with the polymer shuttle. v, Wafer dicing was used to remove the substrate beneath mesh electronics. w, Dip coating of biodegradable PEG solution fixed the mesh electronics to the polymer shuttle. x, Anchor was removed before implantation.
