Bio mems lal-1


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Biomems application

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Bio mems lal-1

  1. 1. From Bioinstrumentation to BioMEMS [email_address] <ul><li>Contents </li></ul><ul><li>Early developments in bio-instrumentation </li></ul><ul><li>Collaboration with other groups </li></ul><ul><li>Sensor materials </li></ul><ul><li>Sensor structures </li></ul><ul><li>bioMEMS </li></ul><ul><li>Will give you a whiff of what we do and what we plan to do! </li></ul>
  2. 2. Early history of bioinstrumentation @ IITB <ul><li>Began with work in the Electrical Department </li></ul><ul><ul><li>Electro-oculography, electromyography, ECG, microprocessor based ECG analyzer, .. </li></ul></ul><ul><li>Other departments </li></ul><ul><ul><li>Mechanical & aeronautical: fluid dynamics & flow (theory and some instrumentation) </li></ul></ul><ul><ul><li>Physics: X-ray imaging & laser applications (mainly theoretical) </li></ul></ul>
  3. 3. Subsequent Developments <ul><li>New developments in EE in bioinstrumentation </li></ul><ul><li>Setting up of the School of Biomedical Engineering </li></ul><ul><ul><li>~ 1987 IITB Senate takes a landmark decision to admit medical graduates in its post-graduate program in BME </li></ul></ul><ul><ul><li>Synergistic development of bio-instrumentation with BME </li></ul></ul><ul><li>Biosensor work with Chemistry & Materials Science </li></ul><ul><li>Sensor & biosensor research in Microelectronics </li></ul>
  4. 4. New developments in EE (1) <ul><li>Mid to late eighties faculty joined with research interests in instrumentation, microelectronics, signal & image processing </li></ul><ul><ul><li>They also had interests in bio-related application areas </li></ul></ul><ul><ul><li>The administration encouraged inter-disciplinary work </li></ul></ul>
  5. 5. New developments in EE (2) <ul><li>Several projects executed on: </li></ul><ul><ul><li>Audiometry </li></ul></ul><ul><ul><li>PC based patient monitoring system </li></ul></ul><ul><ul><li>ECG telemetry & ECG data compression </li></ul></ul><ul><ul><li>Speech recognition </li></ul></ul><ul><ul><li>Aids for the visually challenged </li></ul></ul><ul><ul><li>MRI image enhancement </li></ul></ul>
  6. 6. New developments in EE (3) <ul><li>Electronic Design Laboratory (EDL) projects: </li></ul><ul><ul><li>Prosthetic hand/wrist based on </li></ul></ul><ul><ul><ul><li>(a) EMG activity (b) Simple audio cues </li></ul></ul></ul><ul><ul><li>Aids for the visually challenged </li></ul></ul><ul><ul><ul><li>(a)A clock that reads out time based on audio/inputs </li></ul></ul></ul><ul><ul><ul><li>(b) Several projects on ultrasonic object detectors </li></ul></ul></ul><ul><ul><li>Low cost devices for web-based healthcare delivery </li></ul></ul><ul><ul><ul><li>(a) ECG and other physiological parameters (b) mobile acquisition system for physiological parameter </li></ul></ul></ul><ul><ul><li>Electronic sensing systems for rice polish evaluation </li></ul></ul>
  7. 7. New developments in EE (4) <ul><li>EDL projects (contd): </li></ul><ul><ul><li>ECG recording using a sound card </li></ul></ul><ul><ul><li>Battery driven high-voltage isolated stimulator. </li></ul></ul><ul><ul><li>Water & air quality monitor </li></ul></ul><ul><ul><ul><li>(a)System to measure water quality in Powai lake </li></ul></ul></ul><ul><ul><ul><li>(b) System to measure air quality and noise .. </li></ul></ul></ul><ul><ul><ul><li>(c) Transceiver and PC data acquisition equipment </li></ul></ul></ul><ul><ul><li>Impedance tomography system </li></ul></ul><ul><ul><li>System for single cell electroporation </li></ul></ul>
  8. 8. Bio-instrumentation with SBME <ul><li>Several core faculty members in SBME had interest in instrumentation for their research </li></ul><ul><li>Interaction between EE & SBME faculty and students lead to more realistic projects </li></ul><ul><li>Having SBME on campus increased the engineering faculty’s interaction with doctors and hospitals </li></ul>
  9. 9. Bio-instrumentation with SBME (2) <ul><li>Within SBME: </li></ul><ul><ul><li>Great interest in instrumentation for electrophysiology: a slew of stimulators & signal capture modules (an EMG analyzer sold to industry and is undergoing field trials) </li></ul></ul><ul><ul><li>Biopotential amplifiers </li></ul></ul><ul><ul><li>Instrumentation for hemorheological studies </li></ul></ul><ul><ul><li>Prosthetic hand </li></ul></ul><ul><ul><li>Tele-medicine (several faculty across the institute) </li></ul></ul>
  10. 10. Bio-instrumentation with SBME (3) <ul><li>Jointly EE & SBME: </li></ul><ul><ul><li>Instrumentation for tissue impedance study </li></ul></ul><ul><ul><li>Pulse oximetry </li></ul></ul><ul><ul><li>Audiometry </li></ul></ul><ul><ul><li>Silicon microprobe for potential and strain measurement (an early anisotropic etching project in the country) </li></ul></ul><ul><ul><li>Medical imaging: Diagnostic support for mamography (more info in the communications group site) </li></ul></ul>
  11. 11. Biosensor work with Chemistry <ul><li>Pioneering work on conducting polymers has been conducted in the electrochemistry lab in the Department of Chemistry </li></ul><ul><li>There has been collaborative work with EE to convert some of this knowledge to conducting polymer microsensors & biosensors </li></ul><ul><li>Sensors & instrumentation for: ions & biomolecules realized [Major Media Lab & DBT projects in this area now on] </li></ul>
  12. 12. Why Conducting Polymers? <ul><li>Assaying ions & molecules in aqueous solutions is important for observing biological phenomena </li></ul><ul><li>Problem: Conventional semiconductor chemical sensors are: </li></ul><ul><li>2D devices with a planar interface (gives poor sensitivity) or poly-crystalline devices, & </li></ul><ul><li>Have poor stability in aqueous environments </li></ul>
  13. 13. Conducting polymer ENFET Cross-section of a biosensor Sensor response Substrate Source Drain H +  Enzyme Enzyme catalyzed reaction  H +  /     /  Substrate 0 10 20 30 40 50 60 0.30 0.25 0.20 0.15 0.10 0.05
  14. 14. Sensor materials &  Sensors work in the  ELab <ul><li>For the last two decades faculty in EE have been interested in materials and structures for sensors which has lead on to bioMEMS </li></ul><ul><li>Early interest in materials and structures for physical sensors which moved on to chemical and biochemical sensors </li></ul>
  15. 15. Sensor materials <ul><li>Some materials related work: </li></ul><ul><ul><li>ITO for reducing gas sensors </li></ul></ul><ul><ul><li>Cadmium oxide films by ARE for photometry </li></ul></ul><ul><ul><li>Indium doping of silicon for IR sensors </li></ul></ul>
  16. 16. Some  biosensors in  ELab <ul><li>MOS capacitor based radiation sensors </li></ul><ul><li>EOS based sensors </li></ul><ul><ul><li>ISFET </li></ul></ul><ul><ul><li>Capacitive immunosensor </li></ul></ul><ul><li>bioMEMS </li></ul><ul><ul><li>Silicon micro-electrodes & cantilevers </li></ul></ul><ul><ul><li>Silicon electroporation transducer </li></ul></ul><ul><ul><li> Capillary electrophoresis </li></ul></ul>
  17. 17. Why EOS? <ul><li>Compatible with standard microelectronic processing, therefore the possibility of monolithic systems </li></ul><ul><li>Oxide compatible and used as an containment medium for various bio-objects </li></ul><ul><li>Problems: </li></ul><ul><ul><li>Leaky to proton drifts </li></ul></ul><ul><ul><li>Some cases interface properties not optimum </li></ul></ul>
  18. 18.  Sensors (EOS system based) <ul><li>EOS Capacitors </li></ul><ul><ul><li>For ions & biomolecules (mainly affinity BS) </li></ul></ul><ul><li>ISFETs </li></ul><ul><ul><li>For ions & biomolecules (mainly catalytic BS) </li></ul></ul><ul><li>Sensing systems </li></ul><ul><ul><li>Arrays (proteins, DNA fragments,…) </li></ul></ul><ul><ul><li>Capillary Electrophoresis (proteins, DNA,…) </li></ul></ul><ul><ul><li>Dielectrophoretic systems (cells, organelles,..) </li></ul></ul>
  19. 19. What can be exploited in EOS systems for Biosensors? <ul><li>In MOS Capacitors </li></ul><ul><ul><li>Change of surface charge can modify what is called the high-frequency CV </li></ul></ul><ul><ul><li>For affinity biosensors, change of effective dielectric thickness can be exploited </li></ul></ul><ul><li>In ISFETs </li></ul><ul><ul><li>Change of surface charge can modify the channel charge </li></ul></ul><ul><ul><li>This can be probed as a change of the threshold voltage </li></ul></ul>
  20. 20. EOS Capacitor <ul><li>Two terminal device </li></ul><ul><ul><li>Ions attach to surface sites, modify charge carriers in Si </li></ul></ul><ul><ul><li>Changes CV (note: small signal measurements required) </li></ul></ul>Electrolyte Silicon Oxide Example: EOS capacitor ~
  21. 21. Capacitive affinity biosensors <ul><li>Surface of oxide coated with antibody </li></ul><ul><li>When antigen in analyte present, they diffuse and attach </li></ul><ul><li>Observe change of capacitance </li></ul><ul><li>Using porous silicon improves sensitivity </li></ul>Silicon Antigen Antibody
  22. 22. ISFET <ul><li>A field effect device </li></ul><ul><ul><li>Ions attaching to surface sites modify channel charge </li></ul></ul><ul><ul><li>Channel current therefore modulated </li></ul></ul><ul><ul><li>(note: DC measurements fine  more complex device but simpler instrumentation) </li></ul></ul>P-type silicon N + N + + + + + + - - - - - Source Drain Encapsulation Metal Contacts electrons + [SiO 2 +Si 3 N 4 ] + Analyte + + + + + + A H + + + RE
  23. 23. bioMEMS made in the  Elab: Microelectroporator <ul><li>Single cell micro-electroporator </li></ul><ul><li>Pore etched in silicon so that impedance change can be observed for single cells passing through the pore </li></ul><ul><li>Electroporate when threshold reached </li></ul>
  24. 24. bioMEMS made in the  ELab(2): Microelectroporator SEM & optical micrographs of micro pore
  25. 25. bioMEMS made in the  ELab(3): Microelectroporator Electroporator Cell Pulse output due to a ~15  m particle
  26. 26. bioMEMS made in the  ELab(5):  CE <ul><li>Since biomolecules often charged, they drift in an electric field </li></ul><ul><li>Drift velocity different for different sized molecules or made different using dispersive media </li></ul><ul><li>Different transit times between source & sink used to detect different molecules </li></ul>Source Sink Dispersive drift channel Detector system
  27. 27. bioMEMS made in the  ELab(5):  CE
  28. 28. bioMEMS made in the  ELab(6):  CE
  29. 29. A whiff off what we plan to do <ul><li>Affinity cantilevers for biomolecules </li></ul><ul><li>Conducting polymer arrays for diseases </li></ul><ul><li>Microbial sensors </li></ul><ul><li>“Silicon locket” for cardiovascular monitoring </li></ul><ul><li>Radiation sensors </li></ul>
  30. 30. Conclusions <ul><li>IITB is one of the few places in the country which has demonstrated collaborative work in the area of bio-instrumentation & bio-sensing systems </li></ul><ul><li>These have been demonstrated by student projects and modest consultancy and sponsored projects </li></ul><ul><li>Need projects with critical funding levels to take these ideas to the field and is actively seeking funding and collaboration </li></ul><ul><li>The academic-research structure in the institute is conducive for the realization of the above objective that would create both locally useful bioMEMS based diagnostic systems and globally appreciated new knowledge </li></ul>
  31. 31. The Team (or shall we say morphing teams!) <ul><li>Faculty: </li></ul><ul><ul><li>EE: T Anjaneyulu, SD Agashe, AN Chandorkar, UB Desai, V Gadre, R Lal, PC Pandey, M Patil, R Rao, DK Sharma, J Vasi </li></ul></ul><ul><ul><li>SBME: S Devasahayam, R Manchanda, S Mukherji </li></ul></ul><ul><ul><li>Chemistry: AQ Contractor </li></ul></ul><ul><ul><li>Materials Science: R Srinivasa </li></ul></ul><ul><ul><li>(Expanding as new faculty join with interests in related areas and as we look more seriously at systems on a chip) </li></ul></ul><ul><li>Students: </li></ul><ul><ul><li>Doctoral: M Reddy, G Pathak, S Kolluri, M Mitra, A Topkar, B Prasad, A Betty, A Shastry, …(just the  E students more from other groups) </li></ul></ul><ul><ul><li>M Techs & Dual Degree: ~ a dozen </li></ul></ul><ul><ul><li>B Techs: ~a dozen </li></ul></ul>