Fig. 5.

(a) Schematic illustration of a bioresorbable intracranial pressure sensor, with the inset showing the location of the Si-NM strain gauge; (b) Pressure as a function of time measured by a commercial pressure sensor (blue) and a calibrated bioresorbable device (red); (c) Images of accelerated dissolution of a bioresorbable pressure sensor in a buffer solution (pH 12) enclosed in a PDMS chamber at room temperature; (d) In vivo intracranial pressure measurements for 3 days on a rat model using the device with polyanhydride encapsulation; (e) Confocal fluorescence images of the cortical surface at 2, 4 and 8 weeks (dashed line indicates the site of dissolved device), with glial fibrillary acidic protein (GFAP) to detect astrocytes (red), and ionized calcium-binding adaptor molecule 1 (Iba1) to identify microglia/macrophages (green); (f) Image of the passive bioresorbable neural electrode array; (g) Photograph of a passive four-channel bioresorbable neural device on the cortical surface of a rat; (h) Sleep spindles recorded by bioresorbable passive neural array and the conventional stainless steel electrode as a control on the cortical surface; (i) Accelerated dissolution of a passive bioresorbable neural device at various stages in a buffer solution (pH 10) at 37 °C. Reprinted with permissions from Refs. [18, 19].