(265d) Protein Detection with Peptoid-Functionalized Carbon Nanotube Optical Sensors

Authors: 
Chio, L., University of California
Del Bonis-O'Donnell, J. T., University of California Berkeley
Kline, M. A., Lawrence Berkeley National Laboratory
Zuckermann, R. N., Lawrence Berkeley National Laboratory
Landry, M., Chan Zuckerberg Biohub
A primary limitation to real-time imaging of small molecule metabolites and proteins has been the selective detection of biomolecules that have no naturally-occurring molecular recognition counterpart.1 We present recent developments in the design of synthetic non-photobleaching fluorescent sensors, ‘synthetic antibodies’, to detect protein analytes, based on the near-infrared fluorescence modulation of single-walled carbon nanotubes (SWNT). Bio-mimetic peptoids, or N-substituted glycine polymers, are electrostatically pinned to the surface of SWNT to create peptoid-SWNT sensors sensitive and selective for the lectin protein wheat germ agglutinin.2 We show the sensor to remain functional in Dulbecco’s Modified Eagle’s Medium, suitable for mammalian cell experimentation. The protein sensor is characterized with near-infrared spectroscopy and microscopy to extract protein-sensor interaction parameters and kinetic binding constants. We further show ternary selective interactions of the lectin with its conjugate sugars, through the near-infrared modulation of the peptoid-SWNT. This peptoid-SWNT sensor is a notable demonstration of a synthetic peptoid-nanoparticle biosensor with sugar recognition, and informs us of design considerations for developing synthetic molecular recognition elements to detect proteins and complex biomolecules.

  1. Landry, M. P. et al. Single-molecule detection of protein efflux from microorganisms using fluorescent single-walled carbon nanotube sensor arrays. Nat. Nanotechnol. (2017). doi:10.1038/nnano.2016.284
  2. Olivier, G. K. et al. Antibody-mimetic peptoid nanosheets for molecular recognition. ACS Nano 7, 9276–9286 (2013).