S Outline S Project Background S Design Specifications S Components - PowerPoint PPT Presentation

Not-a-Drop Spectrophotometer Project Update Michael Shang 12.05.2016 S

Outline S Project Background S Design Specifications S Components of a Spectrophotometer S Pugh Analysis S Budget Proposal

Project Background S

Current Market and Need S Market: Low-volume spectrophotometers for measuring concentration of proteins and nucleic acids Nanodrop 2000 Orion AQ8000 S Need: Low-cost instruments for basic analysis of biological samples while preserving sample volume and minimizing contaminants

The Nucleotube S Designed by Spectrum Perception Optical Region Volume: 6 μL S Total Volume: 1.5 mL Body Optical Legs Region

Project Scope S Design and prototype a low-cost spectrophotometer that is compatible with the Nucleotube and measures concentration and purity of nucleic acid samples. S No changes to scope, team responsibilities, or design schedule

Design Specifications S

Product Specifications Absorbance Accuracy +/- 5.0% of known standard across entire range (10% for prototype) Linear from 0.1 – 300 Absorbance Range Repeatability +/- 2.0% between measurements Detection Limit 2.0 ng/µL Measurement Time < 10.0 s Number of Samples Measured at Once 1 S Includes LED display that reports: Absorbance – at 260nm and 280nm wavelengths S S Percent transmittance S Purity - A260/A280 ratio for DNA/RNA applications

Design Considerations S Cost S Accuracy S Ease of Implementation S Portable (size, power required) S Reliability S Sensitivity S Modularity

Components of a Spectrophotometer S

Components: Light Source S Produces UV light that passes through sample to detector S Major influence on all design considerations Deep UV LED Halogen/Deuterium Lamp UV Laser

Components: Optical Guides S Define the path in which light travels through the device S Influences sensitivity and ease of implementation Mirrors/Lens Fiber Optics

Components: Light Detector S Silicon Photodiode S Semiconductor devices that convert light into current S Sensitive in the UV range (190nm-340nm) S Influences sensitivity, cost, modularity Adafruit GUVA-S12SD Detector response curve

Microprocessor and User Interface S Microprocessor – stores, processes, and transfers data S User Interface – touchscreen display that reports absorbance/transmittance, concentration, and purity

Pugh Analysis Spectrophotometer Layout S

Halogen/Deuterium Lamp with Monochromator Advantages Disadvantages Broad-spectrum lamp with Overly complex for intended wavelength selector can applications generate full chromatograph Very expensive Requires stepper motor

Halogen Lamp with Polychromator Advantages Disadvantages Faster measurements More complex than monochromator No moving parts

Linear Design w/ UV-LED Advantages Disadvantages Very simple design Not modular No monochromator needed Reduced accuracy from additional wavelengths in Low power required LED

Modular Design w/ Reflective Lens Advantages Disadvantages Modular design allows Decreased sensitivity due to device to run other assays increased scattering (BCA, Bradford, etc.)

Modular Design w/ Fiber Optic Light Guides Advantages Disadvantages Easier to implement than No additional reflective mirrors Increased sensitivity

Spectrophotometer Layout: Pugh Chart

Microcontroller: Pugh Chart

User Interface: Pugh Chart

Chosen Solution and Budget Component Chosen Solution Cost Light Source 260/280nm Deep $274+$186 UV LED 1/16” Fiber Optics Optical Guides $82.50 Detector Silicon $100 Photodiode UV Detector Microcontroller Adafruit Feather $29.95 M0 Bluefruit LE Display TFT Featherwing $29.95 3D Printing PLA Filament $20.00 Total Budget Requested: $722.40

Questions? Thank you for listening S

Works Cited S Deep UV LED - http://www.roithner-laser.com/deepuv_cross.html S Mirror - https://store.schoolspecialty.com/OA_HTML/ibeCCtpItmDspRte.jsp?minisite=10029&item=36815&gclid=CjwKEAiA94nCBRDxi smumrL83icSJAAeeETQMnNtg6JQ8MmBPOOmxRaVUid2QCgNScOwrx6NzWfkgRoC7q7w_wcB S Photodiode spectrum - http://www.gano-uv.com/admin1234/kindeditor/attached/file/20160106/20160106143281108110.pdf Monochromator figure – S http://chem.libretexts.org/Core/Physical_and_Theoretical_Chemistry/Kinetics/Reaction_Rates/Experimental_Determination_of_ Kinetcs/Spectrophotometry S Adafruit GUVA - https://www.adafruit.com/product/1918 S UV Laser - http://www.crystalaser.com/laser/uv-laser.html S Fiber Optic light guides - https://www.warneronline.com/product_info.cfm?id=1455&name=Flexi.. S Polychromator figure - http://www.hwe.oita-u.ac.jp/kiki/ronnbunn/paper_choi.pdf