Short CommunicationA flexible hydrophilic-modified graphene microprobe for neural and cardiac recording
Graphical abstract
Section snippets
Methods
Fig. 1A shows our design of a novel prototype neural interface using graphene as an electrode and SU-8 as a flexible substrate; SU-8 provides satisfactory biocompatibility, effective electrical insulation, and great flexibility, but one issue for graphene materials is their intrinsically great hydrophobicity, which might lead to a large impedance between graphene and an electrolyte surface. We demonstrate that a graphene surface with a mild steam plasma (SP) significantly increases the
Results
The CVD graphene as-grown of average contact angle was 91.1° ± 5.6° (hydrophobic). The surface of graphene treated at 25 W for 1-s SP was 41° ± 4.7° (hydrophilic) (Fig. S2). Fig. 2A shows our measurement of the spontaneous action potentials (AP) from the axons that run along the abdominal nerve cord of crayfish to confirm the functionality of the microprobe based on graphene. The axons link two ganglions. The spontaneous AP from the axons between the second and third abdominal ganglions were
Discussion
We have demonstrated that the detection of neural and electrocardiographic recording can be carried out by using a graphene-based flexible microprobe. The effect of the SP treatment demonstrates the surface wettability of graphene, the average contact angle decreased from 91.1° ± 5.6° to 41° ± 4.7° (Fig. S2). With the hydrophilic graphene, it becomes feasible to separate electrophysiological signals and to recognize their distinct shapes. The results also show that the electrode yields a larger
Acknowledgments
We thank Professor Fan-Gang Tseng of National Tsing Hua University for providing the fabrication facilities and impedance measurements.
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Cited by (0)
National Science Council of Republic of China (Taiwan) provided partial support through grant NSC 96-2627-E-007-002. Graphene synthesis and characterization were supported by Academia Sincia, Taiwan.