Journal: Sensors & Diagnostics
Article Title: A label-free nanowell-based impedance sensor for ten-minute SARS-CoV-2 detection †
doi: 10.1039/d5sd00002e
Figure Lengend Snippet: (a) Microfabrication procedures for nanowell sensors. Follow the arrows: first step: first 100 nm of the gold electrode after deposition and lift-off; second step: first 40 nm Al 2 O 3 layer by ALD; third step: second 100 nm gold electrode using the same fabrication processes as the first layer; fourth step: second 40 nm Al 2 O 3 layer by ALD; fifth step: zoom-in view of well-shaped arrays in the middle of overlapping area are exposed by multiple etchings for two Al 2 O 3 layers and one gold layer; sixth step: finish connection setup with conductive wires and epoxy, and install PDMS fluidic cell. (b) From left to right: 1. View of a fabricated wafer; 2. Single nanowell sensor; 3. Microscope view of electrodes; 4. Microscope view of 5 × 5 well-shaped arrays.
Article Snippet: A sample is then introduced, and the impedance between electrodes is monitored through lock-in amplifiers (operational frequency: 1 MHz, analog bandwidth: 0.7 μHz–50 MHz, sensitivity: 1 nV to 1.5 V, size: 45 × 35 × 10 cm, gain: 1000, sampling rate: 225 s −1 , HF2IS 50 MHz Lock-in Amplifier, Zurich Instruments AG, Technopark Strasse 1, 8005 Zurich, Switzerland) to determine the presence of the corresponding antigen.
Techniques: Microscopy