Download - Sagar Nadimpalli NSF REU 2010 - 7.29.2010 Bioengineering University of Illinois at Chicago
Sagar Nadimpalli
NSF REU 2010 - 7.29.2010
Bioengineering
University of Illinois at Chicago
NSF (EEC-NSF Grant # 0755115)US D.O.D. ASSUREDirectors
Dr. Christos G. TakoudisDr. Gregory Jursich
Advisor Dr. Alan Feinerman
Graduate Student AdviseeKasun Punchihewa
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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 flow4
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
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Images Courtesy of:http://en.wikipedia.org/wiki/Brain_hemorrhagehttp://biomed.brown.edu/Courses/BI108/2006-108websites/group02glaucoma/glaucoma.html
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 brainThree 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 concentrationsConductivity variations during pressure change
Modeling/Simulation of the pressure sensor design and materials through COMSOL
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Mylar film to create the sensor regionTwo electrodes
Composed of primarily titanium and having a mixture of the followingAluminum (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
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All these materials are considered biocompatible for use2
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1) Pressure Chamber
2) Impedance Analyzer
3) Pressure Gauge
4) Container5) Aquarium Pump6) Pressure flow switch
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Pressure Chamber
Pressure Gauge
Impedance Analyzer
Container Aquarium
PumpPressure Flow Switch
9
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Experimental Testing – Part I
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Experimental Testing – Part IIConductivity vs. Total Pressure
1550
1600
1650
1700
1750
1800
740 760 780 800 820 840 860
Total Pressure (Torr)
Co
nd
uct
ivit
y (m
icro
-Sie
men
s)
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Impedanc e vs . T ime at Various S alt C onc entrations
0.97
0.98
0.99
1
1.01
1.02
1.03
1.04
1.05
1.06
1.07
0 20 40 60 80 100 120 140 160 180 200
T ime (sec onds)
Imp
edan
ce (
k-O
hm
s) S alt - 1g
S alt - 3g
S alt - 5g
S alt -10g
S alt - 15g
S alt - 20g
Experimental Testing – Part III
(Volume = 400 mL*)
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)
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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
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 <http://www.uic.edu/labs/AMReL/NSFREU2009/reports/JUR_REU_Final_Report_Andrew.pdf>.
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.
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