Rapid SARS-CoV-2 Spike Protein Detection by Carbon Nanotube-Based Near-Infrared Nanosensors

Nano Lett. 2021 Mar 10;21(5):2272-2280. doi: 10.1021/acs.nanolett.1c00118. Epub 2021 Feb 26.


To effectively track and eliminate COVID-19, it is critical to develop tools for rapid and accessible diagnosis of actively infected individuals. Here, we introduce a single-walled carbon nanotube (SWCNT)-based optical sensing approach toward this end. We construct a nanosensor based on SWCNTs noncovalently functionalized with ACE2, a host protein with high binding affinity for the SARS-CoV-2 spike protein. The presence of the SARS-CoV-2 spike protein elicits a robust, 2-fold nanosensor fluorescence increase within 90 min of spike protein exposure. We characterize the nanosensor stability and sensing mechanism and passivate the nanosensor to preserve sensing response in saliva and viral transport medium. We further demonstrate that these ACE2-SWCNT nanosensors retain sensing capacity in a surface-immobilized format, exhibiting a 73% fluorescence turn-on response within 5 s of exposure to 35 mg/L SARS-CoV-2 virus-like particles. Our data demonstrate that ACE2-SWCNT nanosensors can be developed into an optical tool for rapid SARS-CoV-2 detection.

Keywords: SARS-CoV-2; carbon nanotube; fluorescence; nanosensor; protein detection.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Angiotensin-Converting Enzyme 2 / metabolism
  • Antigens, Viral / analysis
  • Biosensing Techniques / methods*
  • COVID-19 / diagnosis*
  • COVID-19 / virology*
  • COVID-19 Testing / methods*
  • Humans
  • Immobilized Proteins / metabolism
  • Nanotechnology
  • Nanotubes, Carbon*
  • Pandemics
  • Protein Binding
  • SARS-CoV-2 / chemistry*
  • SARS-CoV-2 / immunology
  • Spectrometry, Fluorescence
  • Spike Glycoprotein, Coronavirus / analysis*
  • Spike Glycoprotein, Coronavirus / immunology
  • Spike Glycoprotein, Coronavirus / metabolism


  • Antigens, Viral
  • Immobilized Proteins
  • Nanotubes, Carbon
  • Spike Glycoprotein, Coronavirus
  • spike protein, SARS-CoV-2
  • ACE2 protein, human
  • Angiotensin-Converting Enzyme 2