Recently, we have shown that rolled-up microtubes made by releasing strained nanomembranes can act as optical resonators. Intense optical mode peaks are evident in photoluminescence signal from this structure. By finite-difference time-domain simulations, it has been confirmed that these optical fields are whispering gallery mode (WGM) type. The evanescent wave of the WGM can coupling to the surrounding and this allows us to use the microtube resonators as on-chip liquid sensing devices. In this talk, we will present our recent development of this technology. First, we are able to fabricate arrays of rolled-up resonators with SiO/SiO2 nanomembranes using photoresist as the sacrificial layer. Second, optical mode peak positions can be tuned by post-deposition of Al2O3 or HfO2 with atomic layer depositions. Third, we experimentally demonstrate the usage of our tube in refractive index sensing of surrounding liquid. Apart from pure dielectric tubes, we also fabricate and couple rolled-up metal/dielectric tubes to conventional waveguides. This system is designed for demonstrating classical and plasmonic waveguiding with our rolledup tubes.