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Rolled-up nanotech [1] has opened up the possibilities of shaping pre-strained nanomembranes into various functional units including optical microtubular cavities,ultra-compact energy storage devices,magnetic sensors,novel concepts for metamaterials and full lab-on-chip systems.The optical microtubular cavities support light to propagate and self-interfere within sub-wavelength-thin cavity walls,leading to the formation of optical whispering-gallery-modes(WGM).In order to improve the quality factor of the WGM resonant modes,a cone-shaped microtube structure has been designed which provides optical axial confinement for novel applications [2].By pumping liquid into the hollow core of the microtubes,optofluidic sensing was investigated where a new measurement strategy was proposed by monitoring the variation of axial mode spacings [3].Due to the sub-wavelength tube wall and relatively small tube diameter,the evanescent field considerably penetrates out of the tube surface allowing for a highly sensitive response to surface molecular changes.As such,molecular dynamic processes on tube surfaces can be detected in real time under ambient conditions [4] and vacuum at low temperatures.The combination of optical resonances with nanomembrane surfaces opens up a promising platform to detect surface phenomena with optical methods.Moreover,overlapping double potential wells were demonstrated due to the existence of quantum dots aggregate embedded in a cone-shaped microtube cavity.The double potential wells produce two independent sets of optical modes.The overlapping mode position can be tuned by modifying the tube cavity,where these mode sets shift with different magnitudes,allowing for a vernier-scale-like tuning effect.In addition,monolithically integrated tube cavities with on-chip waveguides have been fabricated accomplishing a significant step towards 3D photonic integration [5].The ability of our microtube cavities to probe molecular level changes on the sensing surface constitutes a versatile platform for the detection of diverse surface phenomena in a label-free fashion.