Sigma xi presentation (2)

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1. Portable RapidDiagnosticsDisease control for developing countries 2. Project GoalTo build affordable portable rapid diagnosticdevices that can successfully aid in diseasecontrolOur project focused on the mechanical side of the device.The molecular technology used for disease detection willbe covered, but was not a main component of our research. 3. Device FunctionA liquid drop of the sample is placed on a slide,and the drop is physically aligned between theemitting LED and the detecting photodiode andfiber optic receiver. 4. Device purpose and benefit Rapidly diagnose blood and tissue samplesin the field Inexpensive user-friendly device for reliabledisease control device Alert government of problematic diseaseareas quickly and before outbreaks 5. Device Diagram 6. Key Device Features Battery powered - easily available 9V powersource in any country Low power signal - Light Emitting Diode (LED)emission signal with a fiber optic cable andphotodiode to receive the signal after passingthrough the sample Indicator LED - indicator light turns off oncesample is properly aligned Circuit - Operational amplifiers detect amountof light scattering (positive or negative sample) 7. Historical BackgroundRapid Diagnostic Tests (RDTs) are theprefered method of testing samples in the fieldwhere microscopy or a laboratory may not bepracticalRDTs provide a user with a quick reliable wayto classify positive and negative samplesMajor drawbacks of many RDTs is their highcost 8. Technical Features Molecular detection Determining sample scattering Sample Alignment 9. Molecular DetectionDisease detecting antibodies are conjugatedwith gold nanoparticlesIn positive samples,antibodies will clusteraround infectious areas.In negative samples, the antibodies have nopreference for a particular site, and thedistribution will be uniform. 10. Distinguishing SamplesPositive and Negative samples aredistinguished by light scattering from goldnanoparticlesA uniform negative sample will focus lightthrough the drop as expectedA positive sample will have areas of clusteredgold nanoparticles, and create a lower signalreading 11. Sample Alignment 12. Sample AlignmentFor consistent readings, light must hit the dropa the same angle every time.To accomplish this, an optical property ofcurved surfaces is incorporated to ensureproper alignmentOptical caustics aid in the visual alignment 13. Optical CausticsA caustic is the bright pattern of reflected orrefracted light rays on one surface to anotherThe recognizable shape has been used inmany other fields, especially digital imagerendering 14. Application of CausticsA curved surface, in this case a liquid drop,creates a bright area where the signal is mostintenseUsing operational amplifiers, the reading fromthe fiber optic reciever is processed and theindicator LED is shut off when the brightestregion of the caustic is properly aligned 15. Consequences of DeviceConsistent readings can be taken using asimple monochromatic LED.Affordable technology can be used with littletrainingRapid results can be generated and regionalconclusions can be gathered within a day 16. Further Work to DoMagnetic stabilizer - sample alignment iscritical to the device, there are plans toimplement a magnetic coupling to ensureemitter and receptor pieces remain stationaryRechargeable Power Source - the current 9Vsource can take rechargeable 9V batteries. Weare also looking into adding a photovoltaic cellto aid in the recharging batteries 17. Application and ImpactAffordable health care is in constant need inorder to accelerate growth of developingcountriesThis device proves especially helpful in southamerican countries combating the spread ofmosquito transferred diseasesEarly detection can save a government millionsof dollars, as opposed to treating a wide spread 18. AcknowledgementsSokolov K, Follen M, Aaron J, Pavlova (2003)Real-time vital optical imaging of precancerusing anti-epidermal growth factor receptorantibodies conjugated to gold nanoparticles.Johannes Kofler (2004)Focusing of Light in Axially Symmetric Systemswithin the Wave Optics Approximation