Research Article Physiological validation of cell health upon probing with carbon nanotube endoscope and its benefit for single-cell interrogation Zulfiya Orynbayeva, PhD a, ⁎ , Riju Singhal, BS b , Elina A. Vitol, PhD b,1 , Michael G. Schrlau, PhD b , Elizabeth Papazoglou, PhD c , Gary Friedman, PhD d , Yury Gogotsi, PhD, DSc b, ⁎ a Department of Surgery, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA b Department of Materials Science and Engineering, Drexel University, Philadelphia, Pennsylvania, USA c School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania, USA d Department of Electrical and Computer Engineering and A.J. Drexel Nanotechnology Institute, Drexel University, Philadelphia, Pennsylvania, USA Received 3 May 2011; accepted 12 August 2011 Abstract New-generation nanoscale devices for single-cell study are intensively being developed. As has been shown, nanodevices are minimally invasive because of their order-of-magnitude smaller size in comparison to conventional glass pipettes. However, in most studies the evaluation of the nanodevice impact on cell health has not extended to their effects on cell metabolic integrity. In this work we evaluated the degree to which the insertion of a carbon-based nanotube endoscope into a cell induces mechanical and biochemical stress, and affects cellular key metabolic systems. The effects of insertion of the nanotube endoscope on cell morphological and physiological modulations were monitored and compared to those of glass micropipettes. We report that nanotube endoscope insertion does not significantly modulate the plasma membrane and actin network. The cell metabolic mechanisms such as energy production and inositol 1,4,5-trisphosphate– dependent calcium signaling remain preserved for prolonged endoscope presence within a cell. From the Clinical Editor: In this basic science study, the effects of insertion of carbon nanotube endoscope on cell morphological and physiological modulations were monitored and compared to those of glass micropipettes. Nanotube endoscope insertion is truly minimally invasive: it does not significantly modulate the plasma membrane and actin network; the energy production and inositol 1,4,5-trisphosphate– dependent calcium signaling also remain preserved during prolonged endoscope presence within a cell. © 2012 Elsevier Inc. All rights reserved. Key words: Single-cell probing; Carbon nanotubes; Ca 2+ signaling; Mitochondria membrane potential; Actin integrity Fundamental phenomena such as cell protein machinery, cross-talk between organelles, basics of inter- and intracellular signal transductions, and others yet to be discovered can only be completely studied at the nanoscale, which from a physical point of view represents a transition between molecular (insentient) and cellular (life) levels of organization. 1 Typically, biological processes are studied by averaging data collected from millions of cells. However, collective information from these large samples can obscure the discrete nature of biological phenom- ena. For instance, genetic heredity and physiological variability in neighboring cells of the same cell line may cause individual cells to behave differently in response to environmental stimuli 2 and hence impede the study of intracellular processes. Therefore, single-cell and even single-organelle studies are being pursued 3 to support the development of future therapeutics that depend on recognition of the specific cellular features and cellular characteristics of individual patients. Recently, nanoscale tools, such as nanofibers, 4 needle-tipped atomic force microscopy cantilevers, 5-7 and carbon nanotubes and nanopipettes, 8-14 have emerged as the next-generation toolset for single-cell studies. Compared to traditional single-cell probes, such as glass micropipettes, these nanoscale probes are minimally invasive because of their order-of-magnitude smaller size. They also possess unique characteristics, enabling previously unim- agined and complementary intracellular diagnostics such as molecular delivery, cellular mechanics, electrochemistry, and Raman spectroscopy. 13-15 Of particular interest are carbon BASIC SCIENCE Nanomedicine: Nanotechnology, Biology, and Medicine 8 (2012) 590 – 598 nanomedjournal.com This work was supported by a grant from the W.M. Keck Foundation to establish the Keck Institute for Attofluidic Nanotube-based Probes at Drexel University. ⁎ Corresponding authors: Department of Surgery, Drexel University College of Medicine, MS 413, Philadelphia, Pennsylvania 19102, USA. Yury Gogotsi, PhD, DSc, Materials Science and Engineering (383 CAT building), Drexel University, Philadelphia, PA 19104. E-mail addresses: zorynbay@drexelmed.edu (Z. Orynbayeva), gogotsi@drexel.edu (Y. Gogotsi). 1 Current address: Argonne National Laboratory, Argonne, Illinois, USA. 1549-9634/$ – see front matter © 2012 Elsevier Inc. All rights reserved. doi:10.1016/j.nano.2011.08.008 Please cite this article as: Z., Orynbayeva, et al, Physiological validation of cell health upon probing with carbon nanotube endoscope and its benefit for single-cell interrogation. Nanomedicine: NBM 2012;8:590-598, doi:10.1016/j.nano.2011.08.008