Microelectromechanical System-Based Sensing Arrays for Comparative in Vitro Nanotoxicity Assessment at Single Cell and Small Cell-Population Using Electrochemical Impedance Spectroscopy

Abstract

The traditional in vitro nanotoxicity assessment approaches are conducted on a monolayer of cell culture. However, to study a cell response without interference from the neighbor cells, a single cell study is necessary; especially in cases of neuronal, cancerous, and stem cells, wherein an individual cell's fate is often not explained by the whole cell population. Nonetheless, a single cell does not mimic the actual in vivo environment and lacks important information regarding cell communication with its microenvironment. Both a single cell and a cell population provide important and complementary information about cells' behaviors. In this research, we explored nanotoxicity assessment on a single cell and a small cell population using electrochemical impedance spectroscopy and a microelectromechanical system (MEMS) device. We demonstrated a controlled capture of PC12 cells in different-sized microwells (to capture a different number of cells) using a combined method of surface functionalization and dielectrophoresis. The present approach provides a rapid nanotoxicity response as compared to other conventional approaches. This is the first study, to our knowledge, which demonstrates a comparative response of a single cell and small cell colonies on the same MEMS platform, when exposed to metaloxide nanoparticles. We demonstrated that the microenvironment of a cell is also accountable for cells' behaviors and their responses to nanomaterials. The results of this experimental study open up a new hypothesis to be tested for identifying the role of cell communication in spreading toxicity in a cell population.

Recent Advances in the Analysis of Single Cells

“…Highly conductive metal nanoparticles are used in many industrial applications, and the toxicity of nanoparticles got into the public focus. In order to improve the toxicity test for nanoparticles that is traditionally done on well-plate format, Shah et al developed an electrochemical on-chip protocol 144. They implemented electrodes for electrochemical analysis and DEP single cell capture.…”

Nanobiotechnology medical applications: Overcoming challenges through innovation

“…A major advantage of BioMEMS is their ability to perform HTS at an extremely fast rate for many samples (79,80). However, the miniaturization and advancements towards micro-cantilever technology has further increased the accuracy, sensitivity and detection capabilities of BioMEMS while decreasing the cost, the amount of solvent and sample used per assay, and the speed of result acquisition (79,80).The continued trend of miniaturization has led to the generation of cell-on-a-chip technologies that have the capability to perform analysis on the level of single cells (81). Also, organ-on-a-chip technologies have been generated that simulate 3D tissue environments that represent in vivo cell-cell interfaces and can accurately depict biochemical, genetic, and metabolic activities in real time (80,81).…”

“…However, the miniaturization and advancements towards micro-cantilever technology has further increased the accuracy, sensitivity and detection capabilities of BioMEMS while decreasing the cost, the amount of solvent and sample used per assay, and the speed of result acquisition (79,80).The continued trend of miniaturization has led to the generation of cell-on-a-chip technologies that have the capability to perform analysis on the level of single cells (81). Also, organ-on-a-chip technologies have been generated that simulate 3D tissue environments that represent in vivo cell-cell interfaces and can accurately depict biochemical, genetic, and metabolic activities in real time (80,81). These biosensor-based chip technologies have made it possible to detect diseases in their earliest stages due to their extremely small detection limits and their ability to detect the presence of disease cell-by-cell (80,81).…”

“…Also, organ-on-a-chip technologies have been generated that simulate 3D tissue environments that represent in vivo cell-cell interfaces and can accurately depict biochemical, genetic, and metabolic activities in real time (80,81). These biosensor-based chip technologies have made it possible to detect diseases in their earliest stages due to their extremely small detection limits and their ability to detect the presence of disease cell-by-cell (80,81). These technologies will revolutionize in vitro assays and allow simple, non-invasive, inexpensive devices for patient-performed in-home diagnostics.…”

Dielectrophoretic analysis of the impact of isopropyl alcohol on the electric polarisability of Escherichia coli whole-cells

“…Changes in the dielectricity or conductivity, as for dead cells, membrane truncation or different cell phases, affect the electrical impedance and the dielectrophoretic migration, and thus can be detected [8][9][10][11]. Dielectrophresis is the migration of an electrically polarisable object in an inhomogeneous electric field.…”