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Localization and Relative Quantification of Carbon Nanotubes in Cells with Multispectral Imaging Flow Cytometry
Published on: December 12, 2013
Multiplexed multicolor Raman imaging of live cells with isotopically modified single walled carbon nanotubes
Zhuang Liu1, Xiaolin Li, Scott M Tabakman
1Department of Chemistry, Stanford University, Stanford, California 94305, USA.
Abstract:
We show that single walled carbon nanotubes (SWNTs) with different isotope compositions exhibit distinct Raman G-band peaks and can be used for multiplexed multicolor Raman imaging of biological systems. Cancer cells with specific receptors are selectively labeled with three differently "colored" SWNTs conjugated with various targeting ligands including Herceptin (anti-Her2), Erbitux (anti-Her1), and RGD peptide, allowing for multicolor Raman imaging of cells in a multiplexed manner. SWNT Raman signals are highly robust against photobleaching, allowing long-term imaging and tracking. With narrow peak features, SWNT Raman signals are easily differentiated from the autofluorescence background. The SWNT Raman excitation and scattering photons are in the near-infrared region, which is the most transparent optical window for biological systems in vitro and in vivo. Thus, SWNTs are novel Raman tags promising for multiplexed biological detection and imaging.
Insights
Single-walled carbon nanotubes (SWNTs) with distinct isotopic compositions enable multicolor Raman imaging. These robust nanotags allow multiplexed, long-term tracking of targeted cancer cells in biological systems.
Area of Science:
- Nanotechnology
- Biomedical Imaging
- Spectroscopy
Background:
- Raman imaging offers high specificity but faces challenges with multiplexing and photobleaching.
- Autofluorescence and limited optical windows hinder deep tissue imaging.
- Developing novel Raman tags is crucial for advanced biological detection.
Purpose of the Study:
- To demonstrate the use of isotope-engineered single-walled carbon nanotubes (SWNTs) as multicolor Raman tags.
- To enable multiplexed imaging of specific cancer cells using SWNTs conjugated with targeting ligands.
- To evaluate the suitability of SWNTs for long-term, in vitro and in vivo biological imaging.
Main Methods:
- Synthesized SWNTs with varying isotope compositions to achieve distinct Raman G-band shifts.
- Conjugated SWNTs with targeting ligands (Herceptin, Erbitux, RGD peptide) for specific cancer cell labeling.
- Performed multicolor Raman imaging to visualize and track labeled cancer cells.
Main Results:
- Different isotope compositions of SWNTs produced distinct Raman G-band peaks, enabling spectral differentiation.
- Multiplexed imaging successfully labeled and visualized cancer cells targeted by specific ligands.
- SWNT Raman signals demonstrated high photostability and were distinguishable from background autofluorescence.
- Near-infrared excitation and scattering facilitated imaging within the biological optical window.
Conclusions:
- Isotope-engineered SWNTs serve as effective multicolor Raman tags for multiplexed biological imaging.
- SWNTs offer robustness, spectral distinctiveness, and compatibility with near-infrared imaging windows.
- These findings highlight SWNTs as promising tools for advanced cellular detection and tracking in biological systems.
