Extended Data Fig. 1: Test of implantation methods.
From: Brain implantation of soft bioelectronics via embryonic development
a, (Top) schematics showing an atomic force microscopy (AFM) setup for tissue elastic modulus measurement. (Bottom) elastic modulus of stage 15, 24, 32, 40, 48 Xenopus embryos, brain organoids, and cardiac organoids. Box plots indicate minimum, lower quartile, median, upper quartile, and maximum. Each dot represents a contact measurement. b, Photographs showing broken SU-8 mesh post-implantation (left) and the embryo before (middle) and after (right) mesh implantation, depicting damage to the embryo. c, BF microscopic images showing an embryo crushed by SU-8 meshes. d, BF microscopic images showing an embryo successfully implanted with a SEBS mesh. The dashed line circle highlights the portion of the mesh which remains exterior to the tadpole brain. e, Stress-strain curve of PFPE-DMA film with 8 kDa molecular weight, the blue dashed line indicates a linear relationship. f, Stretchability of 8 kDa PFPE-DMA and SU-8 films. g, Surface free energy of 8 kDa PFPE-DMA film and SU-8 films. h, Contact angle of phospholipid (cell membrane analog) on 8 kDa PFPE-DMA film, and on SU-8 film. Bar plots indicate mean ± s.e.m., each dot represents a sample, n = 5. i, Photographic images showing an embryo successfully implanted with a PFPE-DMA mesh. The dashed line circle highlights the portion of the mesh which remains exterior to the tadpole brain. j, Schematics showing how anchors fix the stretchable mesh electronics to the substrate, keeping the neural plate properly positioned during neurulation for device internalization, and keeping the stretchable mesh electrode array attached to the neural plate. The device’s initial dimensions and stretchability enable the stage 15 embryo to be slid under the device for implantation. k, The design of the stretchable mesh electronics showing the architecture of the stretchable mesh electrode array, stretchable serpentine interconnects, anchors, stretchable ribbons, and blockers. The blocker prevents the mesh electrodes from implanting into the caudal region of the neural plate. l, Schematics showing elongation of the neural tube during the embryo development of Xenopus laevis. The caudal region of the neural tube elongates to 3 times its initial length and forms the spinal cord while the cranial region elongates only 1.3 times its initial length and forms the brain.
