Enzyme Biosensor

Enzyme Biosensor

Enzyme BiosensorDetection of glycerides in biodiesel1Team Members:Ben WilsonMatt YourekMegan TempletonMentor: Dr. Tom HessClient: Dr. Dev Shrestha

Opportunity StatementDesign, fabricate, and test a handheld biosensor that uses a modified pH meter combined with an immobilized enzyme electrode to detect the amount of free and total glycerol in a sample of biodiesel.2

Current Industry StandardCurrently biodiesel makers use a gas chromatograph to measure the amount of glycerol within their biodiesel. While the GC provides a very accurate measurement, it is a time consuming process to prepare and test a sample.3

Similar ProductsBlood glucose metersBlood pressure sensorsi-Spec Q-100- uses impedance spectroscopy technology, which is similar to infrared spectroscopy4

Client NeedsSmallLightFast response timeSimple to useAccurateEasy to calibrateReusableStrong/DurableInexpensiveSensitive to small changes in pHUser friendly5Technical SpecificationsDimensions 8x 6x 5Weight of about 2 lbsResponse time of 10 minutes or lessAble to test four samples in one hourError margin of 5% of concentration measurementCan withstand repeated drops from 5ftDoes not bend or flexStorage for electrodeResult is automatically displayed in large numbersTotal of five buttons or lessVisual or audio signal when measurement is completeAudio signal on button pushLarge buttons that take < 3.5lbf to pushMatte/textured finish for added gripBattery operatedTakes user < 5 minutes to change electrodeAutomatic zeroing upon button pushVisual or audio signal for low batteryOne electrode can be used up to 50 timesCosts less than $300 to fabricate

6Instrument Design 1Pros:Very similar to pH meterEasy to store membrane

Cons:Higher chance of damage to electrodeCould experience bad connection between electrode and instrument7

Instrument Design 18

Instrumental Design 19

Instrument Design 2Pros:Simple to useDoesnt need to be held

10Cons:Would need to be more durable/sealedMore complicated to wash and store membrane

Possible MembranesGelatin-Lipase membrane- cited in literature research paperPVA membrane- found during membrane researchPVDF membrane- found during membrane research11

Membrane Design 1Gelatin-Lipase Membrane

Pros:Easy to makeSimilar testing published in papers

Cons:Published paper does not include all informationMembrane falls apart in storage buffer and waterDoes not give reliable mV readings12Membrane Design 2PVA Membrane

Pros:Mechanically strong and flexibleResistant to oil and solventHas ionic conductivity that allows easy flow of electronsUsed in a biosensor to detect glycerides

Cons:Complex process to create membraneWater-soluble, so it might dissolve during reaction13Membrane Design 3PVDF Membrane

Pros:Resistant to acids, bases, and solventsMechanically strongLow cost

Cons:Requires very advanced equipment/techniquesA detailed process to createUsed for the growth of neurons, not typically used with a biosensor14Experimental DataTested both pure canola oil and a biodiesel sample using the gelatin-lipase membrane

The following graphs are the results of millivolt change during the testing process15

Experimental DataPure canola oil sample16

Peak to peak average = 22 mVExperimental DataBiodiesel 30 minute sample (Part 1)17

Peak to peak average = 18 mV Experimental DataBiodiesel 30 minute sample (Part 2)18

Peak to peak average = 18 mVExperimental DataUsing the estimated peak to peak value for each test, as well as the glyceride percent concentration we can obtain the following two point calibration19

Microcontroller Option 1 Arduino UNO with ATmega328

Pros:Easy to use/programComes in design kitsLots of memoryLCD screen comes with wiring instructions for Arduino

Cons:New programming language to learnMinimum voltage input of 6VSlower clock rateProblems could be made worse by mass of online information20

Microcontroller Option 2PICAXE 14M2

Pros:Familiar programming languageFaster clock rateDr. Wolbrecht teaches a class that uses them

Cons:Manufactured and distributed from UKNot much programming help/informationLess memory21

Design SuggestionsInstrument - Design 1, external electrode designMembrane- N/AMicrocontroller- Option 1, Arduino UNO with ATmega328LCD screen- hacktronics LCD screen, comes with Arduino wiring Housing material- ABS 3D printed plastic22Further ExperimentationCreation and testing of PVA and PVDF membranes

Effect of multiple layers of cellulose acetate solution on reaction time and membrane preservation

Relation of mV amplitude to concentration percent

23Detailed ScheduleNov 30 Dec 9: Testing of gelatin-lipase membraneDec 2: SnapshotDec 6: Design reviewChristmas BreakJan 17 Jan 25: Testing of PVA membraneJan 26 Feb 7: Testing of PVDF membraneFeb 8 Feb 24: Finishing touches on design and ordering of any partsFeb 27 Mar 9: FabricationSpring BreakMar 19 Apr 26: ValidationApr 27: Engineering Expo24BudgetMaterials for Membranes: $561Misc. Chemicals: $500Microcontroller: $90LCD Screen: $11Misc. Electronics: $50Housing: $300

Total: $151225Questions?Ben Wilson Mechanical Enginner

Matt Yourek Biological and Agricultural Engineer

Megan Templeton Biological and Agricultural Engineer26