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Ethanol Methadone Opiates Phencyclidine II Propoxyphene Salicylate Tricyclic Antidepressants BIOELECTRONICS AND SAFETY/SECURITY Common aim of much biological/medical.

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Presentation on theme: "Ethanol Methadone Opiates Phencyclidine II Propoxyphene Salicylate Tricyclic Antidepressants BIOELECTRONICS AND SAFETY/SECURITY Common aim of much biological/medical."— Presentation transcript:

1 Ethanol Methadone Opiates Phencyclidine II Propoxyphene Salicylate Tricyclic Antidepressants BIOELECTRONICS AND SAFETY/SECURITY Common aim of much biological/medical diagnostic research and security research detection of biological organisms and organic molecules detection of drugs and explosives at ports and airports; detection of drugs in general; Other areas of medical research, e.g. epidemiology, may also play a role in wider considerations of chemical and biological defence strategies.

2 BIOSENSOR TECHNIQUES MAY BE USEFUL PHYSICAL TRANSDUCER Electronic, e.g. FET Electrochemical, e.g Graphite/Ag-AgCl electrodes Optical, e.g. fibre or planar waveguides BIOLOGICAL MOLECULE: ENZYMES ANTIBODIES Gives the sensor specificity to complex organic molecules

3 Most efforts at developing PCR technology have been aimed at the HTS laboratory where parallelism and automation are used to maximise throughput. For point-of-care or field testing, new approaches are required to allow the rapid processing of single or low numbers of discrete samples. Remote testing often requires that the test has to be carried out by unskilled operators and it may not be possible, in the field, to utilise the control measures used routinely within the lab to minimise contamination. Martin A Lee, Identification Group, Dstl Porton Down

4 Flow through Evanescent Field Immunosensor Thick (multimode) optical fibre Immobilised capture antibody on the surface of the fibre Light out to optical processing Chemiluminescent immunoassay reagents flow through Succesfully developed at Dstl Porton Down but need extensive support to collect, concentrate and measure the analyte

5 Cyclone Concentrator Air sampler Aqueous Buffer Assay Reagents Biosensor Array Display Sensor Outputs Control circuitry Airborne threat Detection of air-borne agents at low concentrations Best suited to a large vehicle

6 Combined Water Filter and Optical Immunosensor

7 MULTI-ANALYTE TESTING COMMON TO BOTH AREAS EXAMPLE, DRUGS OF ABUSE Ethanol Methadone Opiates Phencyclidine II Propoxyphene Salicylate Tricyclic Antidepressants Acetaminophen Amphetamine/ Methamphetamine Barbiturates Benzodiazepines Benzodiazepines-Serum Cannabinoids Cocaine Metabolite Ethanol Methadone Opiates Phencyclidine II Propoxyphene Salicylate Tricyclic Antidepressants

8 CHEMICALLY SENSITIVE FET CHIP: A technique with potential in multi-gate sensing ENCAPSULATED AREA METAL CONTACT PADS BARE GATE: OVERLAY WITH THIN FILM CONTAINING ORGANIC OR BIOMOLECULE, e.g. IONOPHORE: VALINOMYCIN ENZYME: PENICILLINASE BARE GATE FETs FET (conventional) 50 m

9 RESPONSE OF A POTASSIUM SENSITIVE FET Gate membrane - Valinomycin : Dioctyl phthalate : PVC 1:64:35 This success has not been carried through to more relevant analytes Gate compensation voltage constant I ds

10 Penicillin concentration / M Gate compensation voltage constant I ds V g / mV RESPONSE OF A PENICILLIN SENSITIVE FET Gate membrane - Penicillinase entrapped in polyacrylamide Extension from enzyme-based to antibody based FETs is desirable

11 A standard immunoassay procedure

12 Metabolites Therapeutic drugs Small hormones Protein hormones Antibodies Cellular antigens Viral antigens Tumour antigens Analyte conc n moles / litre Glucose TheophyllineDigoxin Oxytocin Aldesterone Cortisol Insulin hCG IgM Rh Hepatitis Influenza (elderly)Influenza (Paediatric) - foetoprotein Analyte molecules per cm 3 Water = 3.3x10 22 Low concentration detection essential in both areas

13 CAPILLARY FILL FLUORESCENCE IMMUNOSENSOR (Manufacture based on LCD cell fabrication) BUFFER LAYER UPPER GLASS FACE THIN FILM WAVEGUIDE LOWER GLASS FACE

14 EQUILIBRIUM RESPONSE CURVE Sensitivity lost on incorporation into CFFD sensor

15 CAPILLARY FILL FLUORESCENCE IMMUNOSENSOR Internal Standards – important in both remote sensing and in medical sensing (to meet FDA requirements)

16 Ethanol Methadone Opiates Phencyclidine II Propoxyphene Salicylate Tricyclic Antidepressants BIOSENSORS AND SAFETY/SECURITY Sensitivity - sacrificed - major problem Microfluidics looks hopeful but yet to deliver Multigate devices Several analytes High specificity – several epitopes Lack of a single detector molecule array processing e.g. neural net Internal calibration


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