Laser-induced graphene interdigitated electrodes for label-free or nanolabel-enhanced highly sensitive capacitive aptamer-based biosensors
AuthorsYagati, Ajay Kumar
Goepferich, Achim M.
Baeumner, Antje J.
Embargo End Date2022-06-01
Permanent link to this recordhttp://hdl.handle.net/10754/667360
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AbstractHighly porous laser-induced graphene (LIG) is easily generated in complex electrode configurations such as interdigitated electrodes (IDEs). Here, we demonstrate that their superior capacitive response at low frequencies can be exploited in affinity biosensors using thrombin aptamers as model biorecognition elements. Of specific interest was the effect of electrode surface area on capacitance detection, and the comparison between a label-free format and enhancement strategies afforded by carboxy group bearing polymeric nanoparticles or liposomes. Electrochemical impedance spectroscopy (EIS) was used to investigate the LIG performance and optimize the biosensor design. Interestingly, the label-free strategy performed extremely well and additional labels decreased the limit of detection or increased the sensitivity only minimally. It is assumed that the highly porous nature of the LIG structures dominates the capacitive response so that labels removed from the surface have only limited influence Also, while slight performance changes can be observed for smaller vs. larger electrode structures, the performance of a LIG IDE is reasonably independent of its size. In the end, a dynamic range of 5 orders of magnitude was obtained (0.01 nM–1000 nM) with a limit of detection as low as 0.12 pM. When measured in serum, this increased to 1.3 pM. The good reproducibility (relative standard deviation (RSD), 4.90%) and repeatability (RSD, 2.59%) and good long-term stability (>7 weeks at 4 °C) prove that a LIG-based capacitance sensor is an excellent choice for affinity-based biosensor. The ease-of-production, the simplicity of modification and the superior performance even in a label-free format indicate that LIG-based biosensors should be considered in point-of-care diagnostics in the future.
CitationYagati, A. K., Behrent, A., Beck, S., Rink, S., Goepferich, A. M., Min, J., … Baeumner, A. J. (2020). Laser-induced graphene interdigitated electrodes for label-free or nanolabel-enhanced highly sensitive capacitive aptamer-based biosensors. Biosensors and Bioelectronics, 164, 112272. doi:10.1016/j.bios.2020.112272
SponsorsAuthors sincerely thank Professor Reinhard Rachel and Mr. Marcel Simsek for providing technical help and assistance in SEM measurements and Ms.Vanessa Tomanek for her contributions to developing the CAD liposome model. This work was supported in part by the South Korean Ministry of Trade, Industry, and Energy (Grant no. P0005440), the South Korean Ministry of Environment (Grant no. 201901136), and the German Federal Ministry of Economic Affairs and Energy (Grant no. ZF4104802AW8). The laser-scriber device was made available through a grant by the King Abdullah University of Science and Technology (KAUST).
JournalBiosensors and Bioelectronics