Self-propelled microjet engines (microbots) can transport multiple cells into specific locations in a fluid. The motion is externally controlled by a magnetic field which allows to selectively load, transport and deliver the cells.

We report a method for the precise capturing of embryonic fibroblast mouse cells into rolled-up microtube resonators. The microtubes contain a nanometer-sized gap in their wall which defines a new type of optofluidic sensor, i.e., a flexible split-wall microtube resonator sensor, employed as a label-free fully integrative detection tool for individual cells. The sensor action works through peak sharpening and spectral shifts of whispering gallery modes within the microresonators under light illumination.

No abstract

Arrays of transparent rolled‐up microtubes can easily be mass‐produced using a combination of conventional photolithography, electron beam depositioning, and chemical etching techniques. Here, we culture primary mouse motor neurons and immortalised CAD cells, a cell line derived from the central nervous system, on various microtube substrates to investigate the influence of topographical surface features on the growth and differentiation behaviour of these cells. Our results indicate that the microtube chips not only support growth of both cell types but also provide a well‐defined, geometrically confined 3D cell culture scaffold. Strikingly, our micropatterns act as a platform for axon guidance with protruding cell extensions aligning in the direction of the microtubes and forming complex square‐shaped grid‐like neurite networks. Our experiments open up a cost‐efficient and bio‐compatible way of analysing single cell behaviour in the context of advanced micro‐/nanostructures with various biological applications ranging from neurite protection studies to cell sensor development.