Miniaturized biosensors and bioanalytical systems promise to revolutionize the field of health care and personalized medicine,in light of sample reduction,speed,and sensitivity.However,mass transport has generally been recognized as a major limiting factor in the sensitivity and performance of miniaturized sensor platforms in that miniaturization poses penalties on passive transport of biomolecules to the sensor surface due to prolonged diffusion length from the bulk liquid or in the direction of the fluidic channels.Further,for low-abundance protein analysis,sample enrichment is often regarded as the first prerequisite for high-resolution analysis,since chemical amplification methods are not readily available for proteins.These factors pose major challenges for early or acute disease diagnostics and biomarker discovery using micro- or nanoscale sensor platforms.To tackle these challenges,we developed nanofluidic and nanoelectronic platforms for the active transport of target analytes to the sensing region.For example,nanoscale molecular dam,using nanoconstriction as field-focusing lens to enhance mass transport,may be used for ultrafast protein enrichment in nanofluidic channels by electrodeless dielectrophoresis [1] under physiological buffer conditions [2-4].On the other hand,sub-10 nm electrode nanogap may be used as an active molecular trap for SERS and tunneling current measurements for low-copy number protein analysis,potentially down to single-molecule level.Our platforms may open up a simple way for heterogeneous protein analysis.