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Microfluidic Impedimetric Cell Regeneration Assay to Monitor the Enhanced Cytotoxic Effect of Nanomaterial Perfusion.

Rothbauer M, Praisler I, Docter D, Stauber RH, Ertl P - Biosensors (Basel) (2015)

Bottom Line: In the last decade, the application of nanomaterials (NMs) in technical products and biomedicine has become a rapidly increasing market trend.To bridge this technological gap, we here present a microfluidic cell culture system containing embedded impedance microsensors to continuously and non-invasively monitor the effects of NMs on adherent cells under varying flow conditions.As a model, the impact of silica NMs on the vitality and regenerative capacity of human lung cells after acute and chronic exposure scenarios was studied over an 18-h period following a four-hour NM treatment.

View Article: PubMed Central - PubMed

Affiliation: BioSensor Technologies, AIT Austrian Institute of Technology GmbH, 1190 Vienna, Austria. mario.rothbauer@gmail.com.

ABSTRACT
In the last decade, the application of nanomaterials (NMs) in technical products and biomedicine has become a rapidly increasing market trend. As the safety and efficacy of NMs are of utmost importance, new methods are needed to study the dynamic interactions of NMs at the nano-biointerface. However, evaluation of NMs based on standard and static cell culture end-point detection methods does not provide information on the dynamics of living biological systems, which is crucial for the understanding of physiological responses. To bridge this technological gap, we here present a microfluidic cell culture system containing embedded impedance microsensors to continuously and non-invasively monitor the effects of NMs on adherent cells under varying flow conditions. As a model, the impact of silica NMs on the vitality and regenerative capacity of human lung cells after acute and chronic exposure scenarios was studied over an 18-h period following a four-hour NM treatment. Results of the study demonstrated that the developed system is applicable to reliably analyze the consequences of dynamic NM exposure to physiological cell barriers in both nanotoxicology and nanomedicine.

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(a) Representative graph of interdigitated electrode structures (IDEs) sensitivity towards H441 epithelial cell monolayers in the range of 1 kHz–500 kHz with the highest signal change indicated in red; (b) typical on-chip adhesion curve of H441 cells (n = 3) on 20 µm × 20 µm IDEs over a period of 70 h; (c) representative graph of IDE response during H441 detachment and reattachment at a frequency of 14 kHz; (d) impedance time trace of H441 cell regeneration and proliferation 4 h post-starvation.
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biosensors-05-00736-f002: (a) Representative graph of interdigitated electrode structures (IDEs) sensitivity towards H441 epithelial cell monolayers in the range of 1 kHz–500 kHz with the highest signal change indicated in red; (b) typical on-chip adhesion curve of H441 cells (n = 3) on 20 µm × 20 µm IDEs over a period of 70 h; (c) representative graph of IDE response during H441 detachment and reattachment at a frequency of 14 kHz; (d) impedance time trace of H441 cell regeneration and proliferation 4 h post-starvation.

Mentions: Since cell type and cell culture origin are known to affect the sensitivity and reproducibility of impedimetric biosensors, it is first necessary to assess biosensor performance using the respective cell culture model under investigation [38,39]. Initial impedance optimization included frequency analysis ranging from 1 kHz–500 kHz to determine the highest sensor sensitivity to H441 lung papillary adenocarcinoma cell lines. In Figure 2a, a representative sensitivity graph is shown exhibiting the highest signal change of 260 Ohms at 14 kHz using the 20-µm IDE sensors (finger-to-spacing ratio of 1:1). Sensor sensitivity is defined as the maximum signal change in the absence and presence of a fully-covered sensor surface with epithelial cells. To reduce the amount of generated data over a 2–3-day cell culture period, single frequency impedance measurements at 14 kHz were used for all subsequent on-chip experiments. To further demonstrate the reproducibility of the on-chip IDE impedance biosensors, cell adhesion curves are recorded in quintuplicates using different biochips and sensors. Results in Figure 2b show an overall signal variation of <10% between the different cell culture chambers at the time of barrier formation (e.g., max. 8.6% deviation from the mean value at t = 70 h), thus demonstrating the reproducibility of the microfluidic cell culture handling procedure. The observed impedance time traces point to similar cell adhesion, spreading and proliferation rates that lead to the establishment of a confluent monolayer and epithelial barrier formation 50 h post-cell seeding, as indicated by the impedance signal plateau.


Microfluidic Impedimetric Cell Regeneration Assay to Monitor the Enhanced Cytotoxic Effect of Nanomaterial Perfusion.

Rothbauer M, Praisler I, Docter D, Stauber RH, Ertl P - Biosensors (Basel) (2015)

(a) Representative graph of interdigitated electrode structures (IDEs) sensitivity towards H441 epithelial cell monolayers in the range of 1 kHz–500 kHz with the highest signal change indicated in red; (b) typical on-chip adhesion curve of H441 cells (n = 3) on 20 µm × 20 µm IDEs over a period of 70 h; (c) representative graph of IDE response during H441 detachment and reattachment at a frequency of 14 kHz; (d) impedance time trace of H441 cell regeneration and proliferation 4 h post-starvation.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4697142&req=5

biosensors-05-00736-f002: (a) Representative graph of interdigitated electrode structures (IDEs) sensitivity towards H441 epithelial cell monolayers in the range of 1 kHz–500 kHz with the highest signal change indicated in red; (b) typical on-chip adhesion curve of H441 cells (n = 3) on 20 µm × 20 µm IDEs over a period of 70 h; (c) representative graph of IDE response during H441 detachment and reattachment at a frequency of 14 kHz; (d) impedance time trace of H441 cell regeneration and proliferation 4 h post-starvation.
Mentions: Since cell type and cell culture origin are known to affect the sensitivity and reproducibility of impedimetric biosensors, it is first necessary to assess biosensor performance using the respective cell culture model under investigation [38,39]. Initial impedance optimization included frequency analysis ranging from 1 kHz–500 kHz to determine the highest sensor sensitivity to H441 lung papillary adenocarcinoma cell lines. In Figure 2a, a representative sensitivity graph is shown exhibiting the highest signal change of 260 Ohms at 14 kHz using the 20-µm IDE sensors (finger-to-spacing ratio of 1:1). Sensor sensitivity is defined as the maximum signal change in the absence and presence of a fully-covered sensor surface with epithelial cells. To reduce the amount of generated data over a 2–3-day cell culture period, single frequency impedance measurements at 14 kHz were used for all subsequent on-chip experiments. To further demonstrate the reproducibility of the on-chip IDE impedance biosensors, cell adhesion curves are recorded in quintuplicates using different biochips and sensors. Results in Figure 2b show an overall signal variation of <10% between the different cell culture chambers at the time of barrier formation (e.g., max. 8.6% deviation from the mean value at t = 70 h), thus demonstrating the reproducibility of the microfluidic cell culture handling procedure. The observed impedance time traces point to similar cell adhesion, spreading and proliferation rates that lead to the establishment of a confluent monolayer and epithelial barrier formation 50 h post-cell seeding, as indicated by the impedance signal plateau.

Bottom Line: In the last decade, the application of nanomaterials (NMs) in technical products and biomedicine has become a rapidly increasing market trend.To bridge this technological gap, we here present a microfluidic cell culture system containing embedded impedance microsensors to continuously and non-invasively monitor the effects of NMs on adherent cells under varying flow conditions.As a model, the impact of silica NMs on the vitality and regenerative capacity of human lung cells after acute and chronic exposure scenarios was studied over an 18-h period following a four-hour NM treatment.

View Article: PubMed Central - PubMed

Affiliation: BioSensor Technologies, AIT Austrian Institute of Technology GmbH, 1190 Vienna, Austria. mario.rothbauer@gmail.com.

ABSTRACT
In the last decade, the application of nanomaterials (NMs) in technical products and biomedicine has become a rapidly increasing market trend. As the safety and efficacy of NMs are of utmost importance, new methods are needed to study the dynamic interactions of NMs at the nano-biointerface. However, evaluation of NMs based on standard and static cell culture end-point detection methods does not provide information on the dynamics of living biological systems, which is crucial for the understanding of physiological responses. To bridge this technological gap, we here present a microfluidic cell culture system containing embedded impedance microsensors to continuously and non-invasively monitor the effects of NMs on adherent cells under varying flow conditions. As a model, the impact of silica NMs on the vitality and regenerative capacity of human lung cells after acute and chronic exposure scenarios was studied over an 18-h period following a four-hour NM treatment. Results of the study demonstrated that the developed system is applicable to reliably analyze the consequences of dynamic NM exposure to physiological cell barriers in both nanotoxicology and nanomedicine.

Show MeSH
Related in: MedlinePlus