Surface‐Functionalized Self‐Standing Microdevices Exhibit Predictive Localization and Seamless Integration in 3D Neural Spheroids

Brain organoids is an exciting technology proposed to advance studies on human brain development, diseases, and possible therapies. Establishing and applying such models, however, is hindered by the lack of technologies to chronically monitor neural activity. A promising new approach comprising self‐standing biosensing microdevices capable of achieving seamless tissue integration during cell aggregation and culture. To date, there is little information on how to control the aggregation of such bioartificial 3D neural assemblies. Here, the growth of hybrid neurospheroids obtained by the aggregation of silicon sham microchips (100 × 100 × 50 μm3) with primary cortical cells is investigated. Results obtained via protein‐binding microchips with different molecules reveal that surface functionalization can tune the integration and final 3D location of self‐standing microdevices into neurospheroids. Morphological and functional characterization suggests that the presence of an integrated microdevice does not alter spheroid growth, cellular composition, nor functional development. Ultimately, cells and microdevices constituting such hybrid neurospheroids can be disaggregated for further single‐cell analysis, and quantifications confirm an unaltered ratio of neurons and glia. These results uncover the potential of surface‐engineered self‐standing microdevices to grow untethered 3D brain tissue models with inbuilt bioelectronic sensors at predefined sites. Microscale bioelectronic devices can provide built‐in biosensing functionalities for routine functional assays in 3D brain tissue models. In this direction, this study reveals the effect of surface functionalization of Si microchips (100 × 100 × 50 µm3) in driving their assembling with cortical cells and in tuning their 3D incorporation inside neurospheroids, without noticeable side‐effects on their development.