Organic Electrochemical Transistors For Monitoring The Extracellular Activity And Electrophysiological Characteristics

The biosafety of nanomaterials has obtained more and more attentions.It is significant to design and develop sensing devices with high sensitivity for the detection of the effects of nanomaterials on the cellular viability and electrophysiological characteristics.Based on the advantages of the organic electrochemical transistors(OECTs),in this paper,the OECT devices using PEDOT:PSS active layer were fabricated by the screen-printing and spin-coating technologies.The AuNPs were prepared by chemical reduction and the graphene oxide-doxorubicin(GO-DXR)hybrids were synthesized by ?-? interaction.By using the human cervical carcinoma cells(HeLa)and mice myocardial cells(H9C2)as models,the effects of nanomaterials on the cellular viability and electrophysiological characteristics were detected by OECTs.The main works are as follows:(1)The OECT devices using PEDOT:PSS active layer were fabricated by screen-printing and spin-coating technologies.The effects of gate electrode and electrolyte on the transfer property and transconductance of the OECTs were investigated in detail.The stability and output property of the OECTs in cellular culture medium were evaluated.The H9C2 cells were seeded onto the PEDOT:PSS film of the OECT devices.The cell morphology and response characteristic of OECTs before and after the seeding of cells were investigated.The results demonstrate that the OECT devices have good adjusting property when the PtNPs/MWCNTs/CP or Ag/AgCl electrode was used as the gate electrode.The OECTs showed good transfer and output properties in the cellular culture medium;moreover,the device is sensitive and stable.The H9C2 cells can adhere and grow on the PEDOT surface,suggesting the good biocompatibility of OECTs.(2)The GO was prepared by mixed acid oxidation.The GO-DXR hybrids were synthesized by ?-? interaction.The spectrum behavior of the GO hybrids,the loading and release of DXR on the GO surface were characterized by UV-vis spectrum.The results suggest that the DXR has been functionalized onto the GO surface.The loading amount of DXR on the GO surface is 2.79 mg/mg.During 24 h,the release of DXR from the GO surface is positively related to the concentration of GO-DXR hybrids.The higher concentration of the hybrids,the more DXR was released.In addition,the amount of released DXR is related to the types of cellular culture medium.At the same concentration of GO-DXR hybrids,the release amount of DXR in the HEME culture medium is larger than that in the RPMI-1640 medium.The effects of GO,DXR,and GO-DXR hybrids on the cell viability of HeLa and H9C2 cells were evaluated by WST-8 assays.The results demonstrate that the cytotoxicity of GO is related the cell type.The GO show no obvious effect on the HeLa cell viability,however,has some effect on the H9C2 cells.The DXR and GO-DXR show concentration-dependent cytotoxicity to HeLa and H9C2 cells.However,at the same concentration,the GO-DXR hybrids show more cytotoxicity to HeLa cells.(3)The OECTs were combined with Transwell.The cell produced H2O2 in the Transwell,which induced by the fMLP peptide,were detected by the OECTs using the PtNPs/MWCNTs/CP gate electrode.By this method,the cellular viability was evaluated by OECTs.The effects of the GO,DXR,and GO-DXR hybrids on the cellular viability of HeLa and H9C2 cells were investigated in detail by the proposed method.The results show that the response of OECT devices(the change of Ids)decreased with the increase of the concentration of the GO,DXR and GO-DXR,which suggest the decrease of the cellular viability.These results were accordant with those obtained by WST-8 assays,indicating the OECTs can be used for evaluation of the effect of nanomaterials on the cellular viability.The effect of AuNPs on the electrophysiological characteristics of H9C2 cells was preliminarily investigated by OECTs using the Ag/AgCl gate electrode.The results demonstrate that the electrophysiological characteristics cannot be identified by the OECTs,which may be due to the weak electrophysiological signal of H9C2 cells and the interference signals.Further experiments are needed.