| Abstract [eng] |
In this dissertation simplification of sensor fabrication for carcinogenic metabolite H2O2 and biomarker carbohydrate antigen 125 sensing is demonstrated. The work explores combining of soft lithography and wet etching for rapid and simplified interdigitated microarray electrode fabrication and also achieving better sensor performance. Unique configuration of electrodes, where interdigitated microarrays are used as working and counter electrodes is explored. Such a configuration can change diffusion of redox active molecules from linear to spherical, which could potentially improve sensing performance. The sensor unique positioning of electrodes were studied by modelling expected electrochemical response using finite difference simulation method. Pt was electroplated at different scan rates controlling structure of Pt and roughness with high precision. This method allows performing the process without toxic agents (lead III), contrary to the established methods. The sensitivity for detection can be tuned by using more in depth data analysis methods for electrochemical impedance spectroscopy such as classical fitting to Randless equivalent circuit or imminence analysis, where components of resistance in impedance Z', Z'' vs frequency plots analysed at single frequencies giving faster data analysis. To improve sensing performance flat electrodes were modified by Au or Pt nanostructure and sensing performance for the first time between Au and Pt nanostructures compared. Nanostructured surface is expected to improve antibody loading, also different electroactivity properties between Au and Pt might lead to better values of sensing parameters such as slope and LOD. Fabricated electrodes can be used for electrochemical applications in biosensing. |
