Detection of Squamous Cell Carcinoma Antigen with Micro- and Nanogap Interdigitated Electrodes and Gold Nanoparticles

Background: Biosensor detects the binding event of biologically relevant molecules, which are analyte and ligand. Showing improved sensitivity is the key and primary characteristic of a high-performance biosensor, which displays lower abundance of an analyte. Here, we preferred the silicon substrate on impedance sensor to demonstrate the improvement in the sensitivity with different band-gaps. Methods: we have fabricated two band-gaps on the sensing substrate with the sizes of micrometer and nanometer. These gaps were measured to be 85.5 ± 5 μm and 125 ± 3 nm, respectively. Squamous cell carcinoma (SCC) antibody and antigen interaction for the cancer detection was demonstrated on these gaps. Results: It was found that nano-gap is having higher sensitivity than micro-gap. Further, gold nanoparticle conjugated SCC antigen was found to show the improvement with the micro-gap. Conclusion: This research has evidenced that lesser band-gap (nano) exhibits a good sensitivity for the detection of SCC antigen rather than micro-gap. Gold nanoparticle conjugation with antigen is suitable for microgaps, whereas no significant improvement with nano-gaps was observed.