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Emerging Sensors and Biosensors for Water Quality Measurements Eric S. McLamore Agricultural & Biological Engineering Department, University of Florida
Emerging Sensors and Biosensors for
Water Quality Measurements
Eric S. McLamore
Agricultural & Biological Engineering Department, University of Florida
• Egyptian pregnancy test (1350 BC)– Barley/wheat germination
• Fetus gender based on the type of grain germinated– Barley growth inhibited --- male child
– Wheat growth inhibited --- female child
• Canary in coal mine
– Coal miners in early 20th century
• Early warning system
– CO and CH3
Confirmed to have 70% accuracy in 1963
Early biodetectors as inspiration
Operating schemeStep 1) Recognition
– Molecular interaction of analyte with immobilized component of sensor
• Formation of analyte-recognition complex
Step 2) Transduction
– Energy is converted into a different form
Step 3) Acquisition
– Recording a useful signal from recognition-transduction sequence
Transduction AcquisitionRecognition
Unique properties of nanomaterialsElectronicPhotonicMagneticMechanical
Physical scale
Atomic scale Bulk scaleNanoscale
• Carbon nanomaterials (tubes, graphene sheets)
• Enhance electrocatalysis (1D and 2D)
• Metal oxides (TiO2, ZnO)
• Enhance photocatalysis
X-ray crystal structure of Au 102p-MBAsub44nanoparticle (http://www-als.lbl.gov)
Emerging sensors
• Frequency modulated fiber optic probes
• Self referencing ion-selective electrodes
– Ag+
• Fate and transport of nanosilver
McLamore et al. (2010), Planta McLamore et al (2011), Sens. Actuat. B: Chemical
Whole cell biosensors• Biotransduction
– Chlorophyll fluorescence
– Enzyme inhibition• Phosphatase and esterase
• Analytes– Herbicides, pesticides, heavy metals
(CH3Hg+ and Hg2+), explosives
• Advantages– Rapid
– Selective
• Challenges– Low signal to noise ratio
– Non specific binding
– Complex preparation (GMO)
Brayner et al ., 2011; Lagarde et al., 2011
Electrode
Immobilized
cells
Electrochemical/
optical
detection
External
analyte
Real Time Biomonitor
•Extant organisms (fathead minnow and daphnia)
•Real time metabolic response (short term and long term)
•Less prone to irreversible damage or hysteresis than
enzymatic sensors
Sanchez et al (2008) Env. Sci. Tech.
CCD or Photodiode arrayCCD or Photodiode array
Blue LED
array
iTOD cartidge
Excitation Filter
1
3
egg
Detector
3
2
• Ab coated
microbeads in a
microfluidic chip
Detection of pathogens
• Electrochemical detection
of β-galacotsidase activity
• Filtered 1 L of water (103
to 107 cfu/mL) and placed
in 10 mL of LB medium
Leskinen et al (2009). J. Water Health. 7(4): 674-684.
Guan et al (2010). Biomed. Microdev.,
12:683-689
Immunoassays• Antibody-hapten conjugates
immobilized on gold film
– Antibody binding
– Change in surface plasmon
resonance
Mauriz et al (2006). Talanta 69 (2006) 359–364
Enzymatic
biosensors
• Oxidase
– Alcohol, glucose, aldehyde, choline, etc.
• Other ezyymes
– Nitrate reductase, hexokinase (ATP)
H2O2 → 2H+ + O2 + 2e-
e-
mediatorred
mediatorox
reactantreduced
productox
enzymeox
enzymered
Adeloju et al (2011), Electroanal., 23: 987-996; McLamore et al (2011) Chem. Soc. Rev.
Electrode
• Lab on chip and biochip
• Nanoprobes
• Oligonucleotide-based biosensors
• Self referencing biosensors
On the horizon?
• On board power: Virus battery
– Belcher et al. (2009), Science
• Nanomotor propelled biosensors
– Claussen et al., (2011) Nano Letters
• Smart Biosensors
Nanoparticle mediated Biosensing:
The Bio-Nano Interface
• Opportunities
– Increased temporal resolution
– Improved sensitivity
– New detection schemes
• Challenges
– Environmental toxicity
– Fouling
– Nanoparticle solubility
Liu et al. (2007) Nature Methods.; Claussen et al. (2009) ACS Nano
