Understanding the interactions of graphene oxide (GO)-based materials with biological systems is critical due to the potential applications of these materials. Here, we investigate the extent to which single- to few-layer GO sheets of different controlled lateral dimensions translocate from the nose to the brain following intranasal instillation. We explore tissue location and in vivo biodegradability of the translocated materials using various techniques. Mass spectrometry and confocal Raman analyses indicate that trace amounts of GO undergo nose-to-brain translocation in a size-dependent manner. The smallest GO-sheet size category (us-GO, 10-550 nm) gains the greatest access to the brain in terms of quantity and coverage. Confocal Raman mapping and immunofluorescence combinations show that in vivo, us-GO resides in association with microglia. Point-and-shoot Raman spectroscopy shows that trace quantities of us-GO are maintained over 1 month, but undergo biodegradation-related changes. This study adds to growing awareness regarding the fate of graphene-based materials in biological systems.

由于这些材料的潜在应用，了解基于氧化石墨烯（GO）的材料与生物系统之间的相互作用至关重要。在这里，我们研究了鼻内滴注后，不同受控横向尺寸的单层或多层GO片从鼻子向大脑移位的程度。我们使用各种技术探索易位材料的组织定位和体内生物降解性。质谱和共聚焦拉曼分析表明，痕量的GO以大小依赖的方式经历了从鼻到脑的移位。最小的GO-sheet尺寸类别（us-GO，10-550 nm）在数量和覆盖范围方面获得了最多的进入大脑的机会。共焦拉曼作图和免疫荧光结合表明在体内，us-GO与小胶质细胞有关。傻瓜式拉曼光谱仪显示，痕量的us-GO可以维持1个月以上，但会发生与生物降解有关的变化。这项研究增加了人们对生物系统中石墨烯基材料的命运的认识。