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