Abstract
The detection and quantification of naturally occurring microbial cellular densities is an essential component of environmental systems monitoring. While there are a number of commonly utilized approaches for monitoring microbial abundance, capacitance-based biosensors represent a promising approach because of their low-cost and label-free detection of microbial cells, but are not as well characterized as more traditional methods. Here, we investigate the applicability of enhanced alternating current electrokinetics (ACEK) capacitive sensing as a new application for rapidly detecting and quantifying microbial cellular densities in cultured and environmentally sourced aquatic samples. ACEK capacitive sensor performance was evaluated using two distinct and dynamic systems – the Great Australian Bight and groundwater from the Oak Ridge Reservation in Oak Ridge, TN. Results demonstrate that ACEK capacitance-based sensing can accurately determine microbial cell counts throughout cellular concentrations typically encountered in naturally occurring microbial communities (103−106 cells/mL). A linear relationship was observed between cellular density and capacitance change correlations, allowing a simple linear curve fitting equation to be used for determining microbial abundances in unknown samples. This work provides a foundation for understanding the limits of capacitance-based sensing in natural environmental samples and supports future efforts focusing on evaluating the robustness ACEK capacitance-based within aquatic environments.
| Original language | English |
|---|---|
| Pages (from-to) | 915-923 |
| Number of pages | 9 |
| Journal | Biosensors and Bioelectronics |
| Volume | 85 |
| DOIs | |
| State | Published - Nov 15 2016 |
Funding
Microsensor work was supported by the University of Tennessee Center for Wildlife Health. Microfabrication of the sensor was conducted at the Center for Nanophase Materials Sciences, which is sponsored at Oak Ridge National Laboratory by the Scientific User Facilities Division, US Department of Energy. Proof of principle groundwater samples from the Oak Ridge Field site and their analysis was supported by Ecosystems and Networks Integrated with Genes and Molecular Assemblies ( http://enigma.lbl.gov ), a Scientific Focus Area Program at Lawrence Berkeley National Laboratory based upon work supported by the U. S. Department of Energy, Office of Science, Office of Biological & Environmental Research under contract number DE-AC02-05CH11231 . Proof of principle seawater samples from Australia were collected under contract A13-0119-001 Deep Sea Basin Microbiology between the University of Tennessee and BP . The authors are grateful to BP and its partners for support in the sampling effort in Australia. We thank N. Alishibi, J. Liu, and C. Chen for their help in culturing samples. We also thank B. Adams for his assistance with editing figures.
Keywords
- AC electrokinetics
- Biosensor
- Interfacial capacitance
- Microbial abundance