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| Bio-engineered Interfaces |
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| (Faculty participants:
Hoath, Mac Neil,
Bhansali, Lindsey,
Hilbelink,
Kumar,
Malik) Areas: Skin, Clinical Sciences, Anatomy, MEMS, and Chemistry |
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| Many biological processes produce
physical, electrical, or chemical alterations that may be monitored by
close approximation of a micro sensor to the surface of the skin. Vital
signals of the human body such as EEG, ECG, and EMG are regularly
measured by the placing of non-invasive electrodes on appropriate parts
of the skin. The primary long-term goal of the project is to understand
the underlying phenomena and dynamics of the human body with the help of
skin as the interface. The more intimate the skin/sensor interface the
better the function of the sensor. Optimizing this interface without
compromising the well being of the organism is a real challenge from
both a biological and an engineering point of view. This group of
studies will focus on how to best design sensors as minimally obtrusive
devices and explore methods to produce a virtual skin model for
incorporation into classic engineering design systems. Our objective is
to optimize the capture of a wide range of signals (electrical activity,
thermal conditions, skin hydration), and to process and analyze this
data for correlated with the physiological state of an individual. |
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| 3D model of human skin for visualization
and finite element modeling |
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| Skin samples containing the three layers
of the integument, will be taken from the thorax, abdomen, back, limbs
and scalp, immediately fixed and processed for light microscopy. Serial
sections will be stained allowing for the visualization of the various
cellular and extracellular components. A single composite digital
montage image of each section will be produced using a collection of
photomicrographs taken at high resolution through a microscope. These
montage images, stacked in Z space and registered in X and Y, result in
a digital data set representing the entire volume of the original tissue
sample. Following a segmentation process, cellular components may be
accurately viewed, either individually or collectively, in 3D space. The
result will be a virtual skin model for use in a CAD environment, for
visualization, finite element analysis and/or simulation studies. |
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| Subsequent phases of the study will involve
the embedding of physiological, biomechanical biochemical, and molecular
data into the virtual model to make the model more robust for
mathematical modeling. This information will be obtained from existing
literature as will as actual analysis of bench related analyses conduct
in our laboratory using such tools as classic tensile strength testing
to atomic force microscopy. |
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| Skin/sensor interface for fluid based
chemical analysis |
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| A non-invasive, CPS micropore binding
interface that could be the front end for the microfluidics based
systems will be developed. We postulate that wicking of endogenous
surface lipids from the skin into the pores will allow device adhesion.
This non-contact/non-invasive sampling technique overcomes the problems
of invasive monitoring. The liquid from the micropores in the active
area is wicked up because of the capillary action and gets introduced
into the sampling chamber. The micropores, however, also act as a check
valve for the fluid from because of large pressure drops across them,
ensuring unidirectional flow of surface analyte. |
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| Skin/sensor interfaces for acoustic
information |
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| Current microsensor technology, wireless
communication, sound waveform analysis, and pattern recognition will be
applied to auscultation. Sounds produced by the heart will be the
primary focus of the study. The initial goal of this study will be to
evaluate current electronic stethoscope technology and the features of
clinically relevant heart sounds to determine the state of the art and
the scope of the challenge. A microsensor-based device will then be
designed to interface between medical personnel and the patient's skin
to optimally sense and capture all relevant auscultation information in
a digital format. |
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