Biosensors.pdf

details of biosensor

1. BIOSENSORS
SAJID HUSSAIN
Asst. Professor
S R Institute of Pharmacy,
Bhuta, Bareilly

2. INTRODUCTION
•Abiosensoris ananalyticaldevice
containinganimmobilizedbiological
material(enzyme,antibody,nucleic
acid,hormone,organelleor whole
cell) whichcan specificallyinteract
withan analyteandproducephysical,
chemicalorelectricalsignalsthatcan
bemeasured.Ananalyte is a
compound(e.g. glucose,urea,drug,
pesticide)whose concentrationhas to
bemeasured.
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3. MAINCOMPONENTSOFABIOSENSOR
•Sensor
•Transducer
•Amplifier
•Processor
•Displayunit
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4. •Sensor
Itisa sensitivebiologicalelement(biological material(eg.tissue,
microorganisms,organelles,cellreceptors,enzymes,antibodies,
nucleicacids,etc).
•Transducer
Transducerisa devicethatconvertsenergyfromoneformto
anotherform.Inbiosensorstransducersconvertthebiochemical
activityintoelectrical energy.
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6. WORKINGPRINCIPLE
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•Biosensorsareoperatedbasedontheprincipleofsignal
transduction.
•Bioreceptor,isallowedtointeractwithaspecificanalyte.The
transducermeasuresthisinteractionandoutputsasignal.The
intensityofthesignaloutputisproportionaltotheconcentrationof
theanalyte. The signalisthenamplifiedandprocessedbythe
electronicsystem.

7. FEATURESOFABIOSENSOR
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a)Itshouldbehighlyspecificfortheanalyte.
b)Thereactionusedshouldbeindependentofmanageablefactors
likepH,temperature,stirring,etc.
c)Theresponseshouldbelinearovera usefulrangeofanalyte
concentrations.
d)Thedeviceshouldbetinyandbio-compatible.
e)Thedeviceshouldbecheap,small,easy touseandcapableof
repeated use.

8. TYPESOFBIOSENSOR
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1.CalorimetricBiosensors
2.PotentiometricBiosensors
3.Acoustic WaveBiosensors
4.AmperometricBiosensors
5.OpticalBiosensors

9. 1.CalorimetricBiosensor
Manyenzymecatalysedreactionsareexothermic,generating
heatwhichmaybe usedas abasisformeasuringtherateofreaction
and,hence,theanalyteconcentration.
Theanalytesolutionispassedthroughasmallpackedbed
columncontainingimmobilizedenzyme;thetemperatureofthe
solutionisdeterminedjustbeforeentryof thesolutionintothecolumn
andjustas itisleavingthe columnusingseparatethermistors.
Anexampleistheuseof glucoseoxidasefordeterminationof
glucose.
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10. 2.PotentiometricBiosensors
Thesebiosensorsuseion-selectiveelectrodestoconvertthe
biologicalreactionintoelectronicsignal.
ManyreactionsgenerateoruseH
+
whichisdetectedand
measuredbythebiosensor.
UreaBiosensorisanexampleof thesebiosensors.
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11. 3.AcousticWaveBiosensors(PiezoelectricBiosensors)
Acousticsensorsusepiezoelectricmaterials,typicallyquartz
crystals,inordertogenerateacousticwaves.
Theirsurfaceisusuallycoatedwithantibodieswhichbindto
thecomplementaryantigenpresentinthesamplesolution.
Thisleadstoincreasedmasswhichreducestheirvibrational
frequency;thischangeisusedtodeterminetheamountofantigen
presentinthesamplesolution.
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12. 4.AmperometricBiosensors
Amperometricbiosensorsfunctionbythe productionof a
currentwhenapotentialisappliedbetweentwoelectrodes.
Themagnitudeof currentbeingproportionaltothesubstrate
concentration.
Thesebiosensorsareusedtomeasureredoxreactions.
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13. 5.OpticalBiosensors
Theseinvolvedeterminingchangesinlightabsorptionbetween
thereactantsandproductsof areaction,ormeasuringthelight
outputbyaluminescentprocess.
Amostpromisingbiosensorinvolvingluminescenceuses
fireflyenzymeluciferasefordetectionofbacteriainfoodor clinical
samples.
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14. APPLICATIONSOFBIOSENSOR
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•Foodanalysis
•StudyofBiomoleculesandtheir
interactions
•Drugdevelopment
•Crimedetection
•Medicaldiagnosis
•Environmentalfieldmonitoring
•Industrialprocesscontrol
•Manufacturing of
pharmaceuticals and
replacementoforgans
•Monitoringglucoselevelin
diabetespatients
•Proteinengineering
•Wastewatertreatment
•Agricultureindustry

15. •Biosensorsin FoodIndustry
Biosensorsareusedforthedetectionof pathogensinfood.
PresenceofEscherichiacoliinvegetables,isabioindicatoroffaecal
contaminationinfood.E.colihasbeenmeasuredbydetecting
variation inpHcausedbyammonia(producedbyurease–E.
coliantibodyconjugate)usingpotentiometricalternatingbiosensing
systems.
Enzymaticbiosensorsarealsoemployedinthedairyindustry.
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16. •Biosensorsin Medicalfield
Glucosebiosensorsarewidelyusedinclinicalapplicationsfor
diagnosisof diabetesmellitus.
Anovelbiosensor,basedon hafniumoxide(HfO
2),hasbeen
usedforearlystagedetectionof humaninterleukin.
Thesearealsousedfordetectionof cardiovasculardiseases.
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17. •BiosensorsinDrugDiscoveryandDrugAnalysis
Enzyme‐basedbiosensorscanbeappliedinthepharmaceutical
industryformonitoringchemicalparametersintheproduction
process(inbioreactors).
Affinitybiosensorsaresuitableforhigh‐throughputscreeningof
bioprocess‐producedantibodiesandfordrugscreening.
Oligonucleotide‐immobilizedbiosensorsforinteractionsstudies
betweenasurfacelinkedDNAandthetargetdrugorforhybridisation
studies.
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18. •RoleofBiosensorsinEnvironmentalMonitoring
Thebiosensorsfindwideapplicationformeasurement,
estimationandcontrolof water,airandsoilcontaminants.
Determinationofthepesticidescanbemadeby
potentiometricbiosensor.
Amperometricbasicsensorcanbe usedforanalysesof water
pollutionfromherbicide.
Concentrationofammoniacanbedefinedwithmicrobe
biosensorwithcellsof typeNitrosomonassp.
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19. •Epigenetics
Photonicbiosensorshavebeendeveloped,whichcandetect
tumorcellinaurinesampletoanultra-sensitivitylevel.
Epigeneticmodificationsaredetectedafter exploitationof
integratedopticalresonators(e.g.,post-translationalmodificationsin
histoneandDNAmethylation)usingbodyfluidsofpatientssuffering
fromcancer orotherailments.
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21. UseofLOCInHIVdetection
•40millionpeopleareinfectedwithHIV..
•1.3 million of these people receive anti-retroviral treatment. Around 90%
ofpeoplewith HIVhaveneverbeentestedforthedisease.
•Measuring the number of CD4+ T lymphocytes in a person’s blood is an
accuratewaytodetermineif a personhas HIV.
•Atthemoment,flowcytometry isthegold standardforobtainingCD4
counts
•Recentlysucha cytometerwas developedforjust $5.
•In such devices it is possible to quickly diagnose and potentially treat
diseases.
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22. UseofLOCforPlantStudies
•Lab-on-a-chipdevicescouldbeusedtocharacterizepollen
tubeguidance.
•Specifically,plantonachipisaminiaturizeddeviceinwhichpollen
tissuesandovulescouldbeincubatedforplantsciencesstudies.
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24. HOWGLUCOSEBIOSENSORWORKS?
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25. FUTUREOFBIOSENSORS
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•BiosensorTechnologyWillDetect—andPotentiallyPrevent—Illness
•BiosensorTechnologyisontheVergeofChanginghowDiabetics
MonitorTheirGlucoseLevels
•BiosensorTechnologyCouldPutanEndtoDrunkDriving
•Greateruseofnanotechnologyandmicrofluidics(LABNACHIP)
•Intelligentcontrolofmedicationdelivery
•Greateruseofhome-basedmonitoringandtreatment

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28. THANKYOU
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