title: Towards intrinsic graphene biosensor: A label-free, suspended single crystalline graphene sensor for multiplex lung cancer tumor markers detection.
abstract: Graphene biosensors reported so far are based on polycrystalline graphene flakes which are anchored on supporting substrates. The influence of grain boundary and the scattering from substrate drastically degrade the properties of graphene and conceal the performance of intrinsic graphene as a sensor. Here we report a label-free biosensor based on suspended single crystalline graphene (SCG), which can get rid of grain boundary and substrate scattering, revealing the biosensing mechanism of intrinsic graphene for the first time. Monolayer SCG flakes were derived from low pressure chemical vapor deposition (LPCVD) method. Multiplex detection of three different lung cancer tumor markers was realized. The suspended structure can largely improve the sensitivity and detection limit (0.1 pg/ml) of the sensor, and the single crystalline nature of SCG enable the biosensor to have superior uniformity compared to polycrystalline ones. The SCG sensors exhibit superb specificity and large linear detection range from 1 pg/ml to 1 μg/ml, showing the prominent advantages of graphene as a sensing material.
authors.affiliation: State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments, Tsinghua University, Beijing 100084, China; Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455, USA.
authors.forename: Peng
authors.initials: P
authors.lastname: Li
authors.affiliation: Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455, USA.
authors.forename: Bo
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455, USA. Electronic address: tcui@me.umn.edu.
authors.forename: Tianhong
authors.initials: T
authors.lastname: Cui
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis*; D015374:Biosensing Techniques / Q000295:instrumentation*; D003460:Crystallization; D004867:Equipment Design; D006108:Graphite / Q000737:chemistry*; D006801:Humans; D057230:Limit of Detection; D008175:Lung Neoplasms / Q000175:diagnosis*; D049329:Nanostructures / Q000737:chemistry / Q000648:ultrastructure
chemical_list: D014408:Biomarkers, Tumor; D006108:Graphite
keywords: Cancer sensor; Graphene; Label-free; Single crystalline; Suspended beam