1. Sagar Nadimpalli NSF REU 2010 - 7.29.2010 Bioengineering University of Illinois at Chicago

2. NSF (EEC-NSF Grant # 0755115) US D.O.D. ASSURE Directors Dr. Christos G. Takoudis Dr. Gregory Jursich Advisor Dr. Alan Feinerman Graduate Student Advisee Kasun Punchihewa 5/23/2015Sagar Nadimpalli REU 2010 2

3. Pressure build-ups or drops in our bodies can influence the blood flow going through the body Specific delicate situations / regions are: CSF [Brain] Glaucoma [Eye (build-up of pressure in this region)] It has been known through various research and modeling with blood mechanics that pressure drops are directly proportional with blood flow 4 If pressure is not detected and monitored carefully Blood flow to that region would be reduced With this in mind, a pressure drop of about 10 Torr for any patient can be means for dealing with a medical situation as a result of this change Images Courtesy of: http://en.wikipedia.org/wiki/Brain_hemorrhage http://biomed.brown.edu/Courses/BI108/2006- 108websites/group02glaucoma/glaucoma.html http://biomed.brown.edu/Courses/BI108/2006- 108websites/group02glaucoma/glaucoma.html 5/23/2015Sagar Nadimpalli REU 2010 3

4. 5/23/2015Sagar Nadimpalli REU 2010 4 Images Courtesy of: http://en.wikipedia.org/wiki/Brain_hemorrhage http://biomed.brown.edu/Courses/BI108/2006- 108websites/group02glaucoma/glaucoma.html

5. To design and test a drift-free biocompatible pressure sensor which measures small variations in applied pressure Can be used for further experimentation as pressure monitoring in various parts of the body (eye for example) Potential for monitoring the CSF variations through pressure monitoring at the brain Three specific tests were performed so far to understand the pressure sensor’s abilities for the body Impedance variations during pressure change and change of salt concentrations Conductivity variations during pressure change Modeling/Simulation of the pressure sensor design and materials through COMSOL 5/23/2015Sagar Nadimpalli REU 2010 5

6. Mylar film to create the sensor region Two electrodes Composed of primarily titanium and having a mixture of the following Aluminum (6%) Vanadium (4%) LDPE (low density polyethylene) tubes 30 cm in length for the center tube 4 cm in length for the part covering each electrode Injected with approx. 0.135 mL of BSS (Balanced Salt Solution) when sensor is ready 5/23/2015Sagar Nadimpalli REU 2010 6

7. All these materials are considered biocompatible for use 2 5/23/2015Sagar Nadimpalli REU 2010 7

8. 1) Pressure Chamber 2) Impedance Analyzer 3) Pressure Gauge 4) Container 5) Aquarium Pump 6) Pressure flow switch 5/23/2015Sagar Nadimpalli REU 2010 8

9. 5/23/2015Sagar Nadimpalli REU 2010 Pressure Chamber Pressure Gauge Impedance Analyzer Container Aquarium Pump Pressure Flow Switch 9

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13. 5/23/2015Sagar Nadimpalli REU 2010 Experimental Testing – Part II

14. 5/23/2015Sagar Nadimpalli REU 2010 Experimental Testing – Part III (Volume = 400 mL*)

15. Run additional simulations regarding the mechanical properties of the biocompatible materials being considered for the upcoming prototypes through COMSOL Make further data runs to better support the current and potential future prototypes of pressure sensor implants Prepare a batch that after having successfully accomplished the safety guidelines for both the properties on an engineered design level and for medical use (research studies through in-vivo usage) 5/23/2015Sagar Nadimpalli REU 2010 15

16. 1) N. Paya, Tatjana Dankovic, and A. Feinerman, “A Microfluidic Mixer Fabricated From Compliant Thermoplastic Films,” Journal of Undergraduate Research 2, pp. 1-5 (2008). http://jur.phy.uic.edu/issue2/JUR-REU0801005.pdf http://jur.phy.uic.edu/issue2/JUR-REU0801005.pdf 2) Beanger MC, Marois Y. Hemocompatibility, biocompatibility, inflammatory and in vivo studies of primary reference materials low-density polyethylene and polydimethylsiloxane: a review. J Biomed Mater Res. 2001;58(5):467-77. Review. 3) A. Duffy, Kasun Punchihewa, and A. Feinerman, “Development of a Meso-scale Drift-free Pressure-sensor for Glaucoma Patients” Journal of Undergraduate Research – NSF REU 2009. 4) Paul, A., Nadimpalli, S., Lin, A., Hsu, Y., "Detailed Model of Blood Flow in the Arms and Legs Using Circuit Analysis." UIC- LPPD-112009, Nov., 2009. 5/23/2015Sagar Nadimpalli REU 2010 16