Method for Measuring Carbon Nanotubes Taken-Up by a Plurality of Living Cells


Carbon nanomaterials (CNMs), including carbon nanotubes (CNTs) and graphene, are undergoing extensive research due to their diverse commercial applications and potential for biomedical uses. The global increase in the production of CNMs and incorporation into consumer products is cause for concern because of the consistent reports that CNMs can be toxic. Furthermore, recent studies have shown that CNTs from anthropogenic sources can reach human lung cells.1 As such, it has become increasingly critical to be able to accurately assess environmental health and safety risks of CNMs. However, it is still difficult to detect all CNT types in aqueous solutions despite the numerous analytical methods available. The need remains for an accessible method of quantifying CNMs in biological and environmental samples. The method presented here for the quantification of CNMs in aqueous solutions, including biological and environmental samples, can determine CNM concentrations as low as 5 ng and only requires a gel electrophoresis unit, a flatbed scanner, and image analysis software. 

Figure 1: Flow diagram for method of measuring CNTs taken-up by living cells.



There is a need for rapid, sensitive, and easily-accessible methods for the quantification of small amounts of CNMs in liquid samples, especially in biological applications.



A label-free method to quantify CNMs from a population of cells has been presented. This method involves the use of polyacrylamide gel electrophoresis (PAGE) in the presence of sodium dodecyl sulfate (SDS), a flatbed scanner, and image analysis software to quantify nanogram amounts of CNMs. 


Technical Summary:

This method of quantifying CNTs consists of SDS-PAGE of CNT standards followed by white light scanning to create a standard curve that may then be used to quantify CNT concentrations in test samples. White light scanning enables the detection of all CNT structures in a sample regardless of whether the CNTs are pristine, oxidized, and/or covalently functionalized. Raman microprobe spectroscopy was used to identify presence of CNTs at the gel interface in order to validate the optical method. CNMs of various dimensions can be selectively concentrated at the gel interface by adjusting the porosity of the gel; the smallest graphene and graphene oxide nanoflakes may be analyzed in a 15% polyacrylamide gel (rather than 4% used for CNTs).


Value Proposition:

This method allows for rapid, sensitive, and inexpensive label-free detection and quantification of carbon nanomaterials (CNMs) in aqueous solutions, including biological and environmental samples.



  • CNMs in blood & tissue extracts.
  • ADMET profiles of CNM constructs
  • CNM parameters involved in the cell accumulation process (e.g., CNM dimensions, concentrations, and surface chemistries)
  • Optimization of the therapeutic efficacy of CNM constructs
  • Environmental Health and safety assessments


Key Benefits:

  • Inexpensive  – Requires only a gel electrophoresis unit, a flatbed scanner, and image analysis software – commonly-available lab equipment
  • Small samples  – Only 1 microliter aliquots needed for quantification
  • Customizable  – CNMs of various dimensions can be measured by adjusting porosity of polyacrylamide gel
  • Sensitive  – Quantifies concentration of all CNT types (i.e. pristine, functionalized, metallic, and semi-conducting) with nanogram sensitivity



Original detailed description of the SDS-PAGE method

Wang, R.; Mikoryak, C.; Chen, E.; Li, S.; Pantano, P. and Draper, R.K. (2009) Gel Electrophoresis Method to Measure the Concentration of Single-Walled Carbon Nanotubes Extracted from Biological Tissue, Analytical Chemistry, 81, 2944-2952.


Use of the SDS-PAGE method in assessing the toxicity of carbon nanotubes

Wang, R.; Mikoryak, C.; Li, S.; Bushdiecker II, D.; Musselman, I.H.; Pantano, P. and Draper, R.K. (2011) Cytotoxicity Screening of Single-Walled Carbon Nanotubes: Detection and Removal of Cytotoxic Contaminants from Carboxylated Carbon Nanotubes, Molecular Pharmaceutics 8, 1351-1361.


Use of the SDS-PAGE method to distinguish the electronic properties of single-walled carbon nanotubes internalized by cells

Chilek, J.C.; Wang, R.; Draper, R.K. and Pantano, P. (2014) Use of Gel Electrophoresis and Raman Spectroscopy to Characterize the Effect of the Electronic Structure of Single-Walled Carbon Nanotubes on Cellular Uptake, Analytical Chemistry 86, 2882-2887.


Use of a modified SDS-PAGE method to detect carbon nanotubes accumulated by an intact aquatic organism

Wang, R.; Meredith, A.N.; Lee Jr., M.L.; Detusch, D.; Miadzvedskaya, L.; Braun, E. Pantano, P.; Harper, S. and Draper, R. (2016) Toxicity Assessment and Bioaccumulation in Zebrafish Embryos Exposed to Carbon Nanotubes Suspended in Pluronic® F-108, Nanotoxicology 10, 689-698.


Use of the SDS-PAGE method to correlate the amounts of cell-accumulated single-walled carbon nanotubes with NIR cell killing efficiencies

Murali, V.S.; Wang, R.; Mikoryak, C.; Pantano, P. and Draper, R.K. (2016) The Impact of Cellular Location on the Near Infrared-Mediated Thermal Ablation of Cells by Targeted Carbon Nanotubes, Nanotechnology 27, 425102 (15 pgs).


Use of the SDS-PAGE method to discover that carboxylated carbon nanotubes are preferentially accumulated relative to pristine carbon nanotubes by a variety of mammalian cell lines

Wang, R.; Lee, Jr., M.; Kinghorn, K.; Hughes, T.; Chuckaree, I.; Lohray, R.; Chow, E.; Pantano, P. and Draper, R.K. (2018) Quantitation of Cell-associated Carbon Nanotubes: Selective Binding and Accumulation of Carboxylated Carbon Nanotubes by Macrophages, Nanotoxicology 12, in press.


IP Status: United States patent 8,632,671 B2 issued on January 21, 2014.

Licensing Opportunity: This technology is available for exclusive or non-exclusive licensing.

ID Number: MP 08-021



1 Kolosnjaj-Tabi, Jelena, et al. “Anthropogenic Carbon Nanotubes Found in the Airways of Parisian Children.” EBioMedicine, vol. 2, no. 11, Oct. 2015, pp. 1697–1704., doi:10.1016/j.ebiom.2015.10.012.

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OTC Licensing
Rockford Draper
Paul Pantano
Ru-Hung Wang
Carole Mikoryak
Carbon Nanomaterials
Carbon Nanotubes
Engineering & Physical Sciences
Life Sciences
Molecular Biology
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