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The many unique properties of graphene, such as the tunable optical, electrical, and plasmonic response make it ideally suited for applications such as biosensing. As with other surface-based biosensors, however, the performance is limited by the diffusive transport of target molecules to the surface. Here we show that atomically sharp edges of monolayer graphene can generate singular electrical field gradients for trapping biomolecules via dielectrophoresis. Graphene-edge dielectrophoresis pushes the physical limit of gradient-force-based trapping by creating atomically sharp tweezers. We have fabricated locally backgated devices with an 8-nm-thick HfO2 dielectric layer and chemical-vapor-deposited graphene to generate 10× higher gradient forces as compared to metal electrodes. We further demonstrate near-100% position-controlled particle trapping at voltages as low as 0.45 V with nanodiamonds, nanobeads, and DNA from bulk solution within seconds. This trapping scheme can be seamlessly integrated with sensors utilizing graphene as well as other two-dimensional materials.
Bibliographical noteFunding Information:
This work was supported by the National Science Foundation (NSF ECCS No. 1610333 to S.-H.O.);
This work was supported by the National Science Foundation (NSF ECCS No. 1610333 to S.-H.O.); The Minnesota Partnership for Biotechnology and Medical Genomics (A.B., S.-H.O., Y.Z., and S.J.K.); J.B.E. acknowledges support from the EPSRC and ERC (Starter and Consolidator grants). A.B. acknowledges support from the University of Minnesota Doctoral Dissertation Fellowship. Device fabrication was performed at the University of Minnesota Nanofabrication Center, which receives support from the NSF through the National Nanotechnology Coordinated Infrastructure (NNCI) program, and the Characterization Facility, which has received capital equipment funding from the NSF through the MRSEC program under award no. DMR-1420013. Computational modeling was carried out using software provided by the University of Minnesota Supercomputing Institute. The authors thank Jonah Shaver for helping with the optics setup and Seon Namgung for helping with sample preparation.
How much support was provided by MRSEC?
Reporting period for MRSEC
- Period 4
PubMed: MeSH publication types
- Journal Article
- Research Support, Non-U.S. Gov't
- Research Support, U.S. Gov't, Non-P.H.S.
11/1/14 → …
Project: Research project