A three-dimensional electrochemical biosensor integrated with hydrogel for cells culture and lactate release monitoring

•We developed a 3D lactate electrochemical sensor by layer-by-layer assembly of carbon nanotubes, Prussian blue nanoparticles and lactate oxidase on a 3D scaffold electrode.•Further, the 3D sensor was integrated with collagen hydrogel with C6 glioma cells seeded therein and allowed the successful real-time monitoring of lactate released from C6 glioma cells, providing an effective detection platform for exploring the biochemical response in 3D cell culture systems.