摘要:SummaryIn vivotwo-photon deep imaging with a broad field of view has revealed functional connectivity among brain regions. Here, we developed a novel observation method that utilizes a polyethylene-oxide-coated CYTOP (PEO-CYTOP) nanosheet with a thickness of ∼130 nm that exhibited a water retention effect and a hydrophilized adhesive surface. PEO-CYTOP nanosheets firmly adhered to brain surfaces, which suppressed bleeding from superficial veins. By taking advantage of the excellent optical properties of PEO-CYTOP nanosheets, we performedin vivodeep imaging in mouse brains at high resolution. Moreover, PEO-CYTOP nanosheets enabled to prepare large cranial windows, achievingin vivoimaging of neural structure and Ca2+elevation in a large field of view. Furthermore, the PEO-CYTOP nanosheets functioned as a sealing material, even after the removal of the dura. These results indicate that this method would be suitable for the investigation of neural functions that are composed of interactions among multiple regions.Graphical AbstractDisplay OmittedHighlights•PEO-CYTOP nanosheet enablesin vivodeep brain imaging in a vast field of view•The 130 nm thickness and the hydrophilized surface realize the strong adhesiveness•Suppressions of bleeding from the surface and inflammation in long-term are achieved•The vast and transparent cranial window with natural curvature of the surfaceOptical Imaging; Techniques in Neuroscience; Nanomaterials