Multiplexed five-color molecular imaging of cancer cells and tumor tissues with carbon nanotube Raman tags in the near-infrared

TL;DR

This paper demonstrates five-color multiplexed molecular imaging of cancer cells and tissues using carbon nanotube Raman tags in the near-infrared, enabling highly specific, background-free imaging with novel five-color capability.

Contribution

The study introduces the first five-color multiplexed Raman imaging in the NIR region using isotope-labeled carbon nanotubes, advancing molecular imaging techniques.

Findings

Successful synthesis of five distinct isotope-labeled SWNTs with separated Raman peaks

Effective multiplexed imaging of live cells and tumor tissues with minimal background interference

Discovery of increased EGFR expression in tumor progression stages

Abstract

Single-walled carbon nanotubes (SWNTs) with five different C13/C12 isotope compositions and well-separated Raman peaks have been synthesized and conjugated to five targeting ligands in order to impart molecular specificity. Multiplexed Raman imaging of live cells has been carried out by highly specific staining of cells with a five-color mixture of SWNTs. Ex vivo multiplexed Raman imaging of tumor samples uncovers a surprising up-regulation of epidermal growth factor receptor (EGFR) on LS174T colon cancer cells from cell culture to in vivo tumor growth. This is the first time five-color multiplexed molecular imaging has been performed in the near-infrared (NIR) region under a single laser excitation. Near zero interfering background of imaging is achieved due to the sharp Raman peaks unique to nanotubes over the low, smooth autofluorescence background of biological species.