Nano-plasmonics, an emerging branch field of nanophotonics concerning properties of collective electronic excitations (surface plasmon, SP) in nanostructures of noble metals (e.g. silver and gold), has attracted intense attention due to its versatility for optical sensing and chip-based device integration. This talk covers our recent work developing a chip-based nanostructure metal film towards a nano-optofluidic device that incorporates an optical transmission sensing scheme with a function of size-dependent sample delivery in a single nanoscale unit. The device has been tested for delivery and detection of a couple disease related protein biomarkers (f-PSA for prostate cancer and anti-insulin antibody of type 1 diabetes (T1D)) as proof-of-concept, which offers a promise for development of a point-of-care technology in health care.