Lithography-free interdigitated electrodes by trench-filling patterning on polymer substrate for Alzheimer's disease detection

Microelectrodes have played a crucial role in electrochemistry for the last few decades. However, the conventional lithographic processes, the key players in fabrication, are nonetheless technologically challenging, pricey, and lack reproducibility. In this work has developed a novel and low-cost patterned-replication fabrication technology for interdigitated electrode array (IDA) electrodes on the polymer substrate. Conventional UVlithography has been utilized to fabricate the nickel IDA electrode pattern as a master mold on the stainlesssteel substrate, which was replicated onto the polymer substrate by the hot-emboss technique. Then, gold was deposited on the replicated wafer by electron beam evaporation, and finally adhesive tape lift-off was used to obtain the gold IDA electrode. The fabricated IDA electrode was applied for electrochemical detection of various p-aminophenol (PAP) concentrations as a representative biomarker with a detection limit of 0.01 nM. Finally, different levels of amyloid beta 42 (Ass42) and amyloid beta aggregated (Ass Agg.), two Alzheimer's disease (AD) biomarkers, were measured using the developed IDA electrode via e-ELISA using enzyme by-products PAP. While quantified, the proposed IDA electrode successfully detects Ass42 and Ass Agg. with the lower detection limit (LOD) of 3.9 and 7.81 pg/ml, respectively.

Automated summary

In this work, a novel and low-cost fabrication technology for interdigitated electrode array (IDA) electrodes on the polymer substrate was developed. The fabricated IDA electrode showed high sensitivity and detection limit in electrochemical detection of biomarkers.