application of cell chip for detection of environmnental toxicants
TRANSCRIPT
Zohaib Hussain (sp13-bty-001)
Application of cell chip for detection of environmental toxicants
A cell-based chip was recently developed and shown to be an effective in vitro tool for analyzing
effect of environmental toxin on target cells. However, common cell chips are inappropriate for
the detection of multiple environmental toxins. Here, we fabricated a cell chip to detect different
cellular responses.
Why we need to use the cell based sensors.
• The cell-based biosensors provide a biologically relevant response to toxic compounds
and mixtures
• Contrary to analytical chemistry methods, non specific but integrative detection
• They Can be extremely sensitive in some cases
• They are not only for environmental sensing, but enormous potential in toxicology
screening of chemical and pharmacological compounds
Type of cell used
1. Mammalian cell
Characteristics are as fallows
• Non-specific toxicity detection
• Strict incubation conditions
• Already used for in-vitro toxicology screening in pharma research
Challenges
• Find best detection methods
• Microbioreactor: long term culture, proliferation
• Sampling environment water while keeping good culture conditions
• Question of the variability and reference measurement
Zohaib Hussain (sp13-bty-001)
2. Bacterial cell
Characteristics are as fallows
Specificity to chemical compounds
• Easy to incubate
• Already proven in environmental measurements
• No automated instrument yet
Challenges
• Storage/conditionning, continuous measurement
• Question of the reference or control measurement
• Design or selection of new bacterial genotypes for new chemical compounds
Examples
1. Bacterial biosensors in microfluidic chips
Encapsulate the bacteria in agarose beads. Trapping of the beads on chip for fluorescent
and electrochemical detection
Zohaib Hussain (sp13-bty-001)
• Frozen samples (-20°C) show very good response
• Tested with fluorescence micro sensor at HES-SO and with electrochemical sensors developed by LEPA
2. Electrochemical measurements with bacterial biosensors
• LacZ reporter gene for expression of beta-galactosidase
• Can be detected by amperometry
• Microfluidic device that allows the trapping of living cells with magnetic beads
• Continuous flow monitoring
10 µM As
tap
Zohaib Hussain (sp13-bty-001)
3. Trans Epithelial Electrical Resistance (TEER)
Cell model: CaCo-2, human colon carcinoma cell line. 21 days in culture, Ultra-thin silicon nitride membranes
4. Cell contractility toxicology assay
Many environmental toxins interfere with cell homeostasis and thereby impact cell contractility. Probing for changes in cell contractility using a nanopillar array and measurement of pillar displacement by a camera.
Zohaib Hussain (sp13-bty-001)
5. System integration
Others applications are
5. Glucose and lactate sensor
6. Regulating osmolarity of the sample
7. Liver cell bioreactor
8. Fluorescence detection with bacterial biosensors
Microfluidic cell incubator
Fluorescence sensors
µ processor + GSM module
Power supply
Micropumps for perfusion