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Bacteria Actuation, Sensing, and Transport (BAST) in Micro/Nanoscale

Bacteria Actuation, Sensing, and Transport (BAST) in Micro/Nanoscale. Dr. MinJun Kim Dept. of Mechanical Engineering & Mechanics Drexel University. Layout of This Presentation. 1. Introduction of Flagellated Bacteria.

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Bacteria Actuation, Sensing, and Transport (BAST) in Micro/Nanoscale

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  1. Bacteria Actuation, Sensing, and Transport (BAST) in Micro/Nanoscale Dr. MinJun Kim Dept. of Mechanical Engineering & Mechanics Drexel University

  2. Layout of This Presentation 1. Introduction of Flagellated Bacteria 2. Microscale Bacterial Actuation- Chaotic Microfluidic Mixing System- Chemotactic Bacterial Sensing System- Self-sustained Microfluidic Pump- Autonomous Bacterial Transportation System 3. Nanoscale Bacterial Actuation- Nanoscale Mechanical Actuator- Flagella-templated Nantube 4. Microbial Risk Assessment- Ultra-fast Bacteria Detection and Configuration- Rapid Bacteria Cell Lysis 5. Conclusions & Acknowledgements

  3. Going Micro & Nano: Miniaturization Theory Why do we need it? - Reduced fabrication cost - Reduced sample consumption - High sample throughput - Superior performance (speed / efficiency) - MEMS and NEMS compatible What are the applications? - Molecular separations - Chemical and biological synthesis - Medical and clinical diagnostics - Environmental monitoring - DNA sequence analysis - Process control Why not use “nature”? - Challenge to micron-nano scale actuation - Intergration Engineering with Biology Self-powered Bacterial Pump

  4. Flagellated Bacteria (E.coli & Serratia marcescens) A cell of E. coli, fluorescently labeled.(Turner, Ryu, and Berg 2000) http://www.npn.jst.go.jp/ Namba 1m • Flagellated Bacteria: • - Cell body & Flagella • - Rod-shaped cell body : 2 m long, 1 m diameter • - Flagella : rotary motor, hook, and filament 10 m 2 m

  5. 25 nm E.coli Rotary Motor, Hook, and Filament • Filament – typically about 10 m and 20 nm in diameter. Helical shape in the unstressed state. • Hook – about 50 nm long and 20 nm in diameter. Plays the universal joint. • Motor – proton (H+) is the energy source. The typical rotation speed is about 100 Hz. The motor can rotate either direction. Schematic diagram (Berg, 2003), electron micro-scopy image of the flagella motor (De Rosier, 1998), and http://www.npn.jst.go.jp/Namba

  6. E.coli in Motion • E. coli swim by rotating helical filaments. • Filaments form a bundle and disperse the bundle. • Tumbles and runs change the swimming directions. Sequence of E. coli flagella bundling (Turner, Ryu, and Berg, 2000)

  7. Macro-scale Model of Bacterial Flagellar Bundling Setup Two stepper motors. Epoxy-filled plastic tubes in helical shape. High viscosity silicone oil (100,000 cp). Match geometry Pitch, Aspect ratio, Number of turns. Match flow characteristics Reynolds number  10-3 (Re  10-5 for Bacteria). Model Full-Scale Fluid 10 5 cP 1cP Flagella: 10 cm 10 um Rotation: 0.3 Hz 100 Hz [ FRONT VIEW ] [ SIDE VIEW ]

  8. Flow by Bundles Helices - Flexible Helices Movie (Real time) - Complex flow field induced by bundling -Bundled state resembles single helix flow ~ Double thickness helix Bundled helices

  9. Test Geometry & Experimental Setup • Buffer + 0.02% of FITC + Dextran (MW=77,000) 0.97 cp @ 24.3 C (a) Width = 200 m Fluorescence Depth = 40 m No Fluorescence (b) (b) Buffer + 0.02% of Dextran (MW=68,800)  0.98 cp @ 24.3 C • PDMS Microchannels Using Soft-Lithography Techniques • E.coli: Tumbly (RP 1616), Wild type (HCB 33), and Immobile • Concentrations of E. Coli: 0 ~ 109 /ml • Flowrate: 0.5 ~ 1.25 l/min • Velocity: 1 ~ 2 mm/s

  10. Flow channel wall Bacteria-Enhanced Diffusion Fixed at U = 1.04 mm/s x = 24 mm. Each Concentration of E.coli = 1.05  109/ml. <Baseline> <Immobile E.coli> <Tumbly E.coli> <Wild type E.coli>

  11. 1. 1 3. 2 3 5. 7. Chemotactic Bacteria-Sensors Sudden Change Bacteria’s Chemotatic Receptors Rotary Motor Performance Affected Global Microfluidic Effects Monitoring or Detecting Bio-Sensor

  12. Controlled-Mixing in Microfluidics

  13. PDMS wall Glass wall Formation of Bacterial Carpets • Concentration of Serratia Marcescens • : 2 ~ 5  109/ml • Time : ~ 1 hour • Flow rate : 0.06 l/min • On : 10 seconds • Off : 5 minutes repeatedly …etc… 15 m Flow …etc… MJ Kim and KS Breuer, PNAS, 2007

  14. Cell Orientation on Bacterial Carpets Bacterial Carpet: 50 m x 50 m -30 < degree < 30 : 54.9013% -40 < degree < 40 : 64.3485% -50 < degree < 50 : 74.5086% Single Cell : 80.5192 % Group Cell : 19.4808 %

  15. Chaotic Mixing with Bacterial Carpet Width: 200 m Depth: 15 m Baseline Dead Bacterial Carpet Live Bacterial Carpet Live Bacterial Carpet Dead Bacterial Carpet Baseline Active bacterial carpet in the microchannel (1 micron dia. fluorescence bead motion) MJ Kim and KS Breuer, JFE, 2007

  16. Autonomous Bacterial Pumping System  • Coat surface of racetrack with Serratia marcesens using flow-deposited carpet • Seed with 500 nm fluorescent particles • Pumping velocities ~ 10 m/sec in the racetrack microchannel MJ Kim and KS Breuer, APS DFD Meeting. 2004

  17. Various Effects on Bacterial Microfluidic Pumps Fully Developed Pumping Velocity MJ Kim and KS Breuer, PNAS, In review. 2007 Pumping Enhancements in the Open System: 1) Glucose (Food) Effects • Flagellar Motor Acitivities • Large-scale Self-coordinations 2) Geometric Effects

  18. PDMS barge Glass substrate Autonomous Bacterial Transportation System Micro-Barges: - Fill Factor: 90 ~ 95 % - Typical Velocity : ~ 5 m/s - Chemotaxis, Phototaxis, and Aerotaxis

  19. Microbarges in Motion

  20. Engineered Bacterial Systems

  21. Cell Patterning Using Colloidal Lithography DK Yi, MJ Kim, et al. Biotech. Lett, 2006

  22. Conclusions ACKNOWLEDGEMENTS: E. Steager (Ph.D), R. Mulero (Ph.D), C.-B Kim (PostDoc), C. Naik (UG), J. Patel (UG), L. Reber (UG), S. Bith (UG). Kenny Breuer, Tom Powers (Brown), Howard Berg, Linda Turner (Harvard), Nick Darnton (U.Mass), MunJu Kim (U.Pittsburgh).

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