Ever since their discovery in 1991, Carbon nanotubes (CNTs) have gained a lot of interest due to their many unique physical and chemical properties. They are almost one dimensional structures with high mechanical strength (100 times stronger than Steel), ultra-light weight (1/6th the weight of steel) and exhibit excellent electrical and thermal conductivity. Most importantly, CNTs have the ability to effectively cross biological barriers and cellular membrane allowing their use in a wide spectrum of biomedical applications such as bio-imaging, disease targeting and the delivery of therapeutic molecules, genes or drugs.
Currently, advances in the biomedical applications of CNTs are being hindered by many uncertainties regarding their cellular uptake mechanisms and fate inside the body. Recent reports have shown that CNTs toxicity can be attributed to metal impurities, length, size, surface area, aggregation, coating, immobilization, uptake, or internalization, to name a few. However; up to now there are no compelling reports that provide fundamental understanding of the toxicological and pharmacological profiles of cellular systems exposed to CNTs with different chemical and physical properties.
Conventional methods to assess the toxicity of CNTs rely on bio-cellular and optical microscopy assays performed at certain time points. These essays provide an overview of the toxicological profiles associated with CNTs exposure by analyzing protein expressions, gene expression, cellular viability, morphology at discrete time points. However; The majority of these essays provide a single analysis of one cellular aspect at a time, which means that we can't study more than one cellular variable at a time, and we can't use the same sample for multiple time points. Also, Most of these assays require intensive sample preparation and the use of markers that interfere in the cellular processes. These limitations hinder our understanding of the cellular behavior associated with CNTs.
In this research, we are introducing a novel technique to study and assess the cellular behavior post exposure to CNTs with different physical and chemical properties. Our approach relies on using the insulating nature of the cellular plasma membrane to monitor and analyze the cellular behavior of human lung epithelial cells in real time. Using an electrical cell impedance sensing (ECIS) device, we can measure and quantify changes in the cellular behavior, morphology, interactions in real time. These measurements will be further analyzed to derive structure-function relations that correlates the cellular mechanisms with the cytotoxic and apoptotic events associated with CNTs exposure in real time.
The ECIS device, in principle, is an electrolytic circuit. It measures the changes in resistance value between an active electrode where the cells are attached and a counter electrode using the growth media as an electrolyte (figure 1)....