SWCNT Biosensor Resistance Measurement for SARS-CoV-2 Detection

The patent changes the detection parameter from conventional antibody-antigen binding measurement to resistance measurement using SWCNTs. The SWCNTs undergo work function modification when binding to viral particles, causing measurable resistance changes. This parameter change enables detection of much lower viral concentrations (177 TCID50/mL) compared to rapid antigen tests, while maintaining the simplicity and speed of the assay.

The patent uses composite materials by functionalizing SWCNTs with heparin or other molecules that enhance viral binding. This composite structure combines the high surface area and electrical properties of SWCNTs with the specific binding capabilities of functional molecules, achieving both high sensitivity and rapid detection without requiring complex equipment.

The patent replaces the complex mechanical and chemical amplification system of qRT-PCR with a direct electrical measurement system using SWCNTs. Instead of requiring thermal cycling, enzymatic reactions, and fluorescent detection, the SWCNT sensor directly measures resistance changes caused by viral binding, achieving comparable or superior sensitivity in seconds to minutes without expensive instrumentation.

The patent extracts and utilizes the work function modification effect of SWCNTs when binding to viruses, isolating this specific physical phenomenon from the complex qRT-PCR process. By focusing solely on the electrical property change rather than requiring nucleic acid amplification, the assay achieves rapid detection with simplified methodology while maintaining high sensitivity.

The patent adopts disposable SWCNT sensors fabricated on inexpensive substrates such as PET film or glass slides, eliminating the need for expensive silicon chip fabrication. These single-use sensors can be mass-produced using simple coating techniques, achieving sufficient detection sensitivity at a fraction of the cost of silicon-based sensors, making them suitable for widespread screening applications.

The patent uses thin film substrates like PET film instead of rigid silicon chips for SWCNT sensor fabrication. This approach dramatically reduces material costs and enables flexible, lightweight sensor designs that can be manufactured at scale using simple deposition techniques. The thin film substrate maintains electrical properties sufficient for detection while eliminating the high fabrication costs associated with silicon processing.