Fig. 1: Example of nanoprobing using optical fibres combined with waveguiding materials tagged with fluorescent QDs.

a Diagram of a nanowire-based cell endoscope; b diagram of a blue laser waveguided through a SnO₂ nanowire attached to the tip of an optical fibre; c, d dark-field images of the nanowire-based cell endoscope before (c) and during (d) deformation by a tungsten needle to demonstrate its flexibility and robustness. The yellow arrows in b–d indicate the position of the nanowire tip where light emission into free space occurs. e–g Intensity emission profiles for an endoscope immersed in a cell culture medium, in which fluorescent proteins are illuminated with blue light from the nanowire tip; e diagram, f top-view dark-field image, and g top-view fluorescence image (a 442 nm longpass filter was applied). Scale bars 50 μm. Reproduced from ref. ¹²⁴