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ICES
PROJECT HIGHLIGHTS
BIOMEDICAL
ENGINEERING AT ICES
ICES is a significant contributor to biomedical and health engineering
research and education at CMU. ICES is currently supporting six biomedical
engineering projects in 2002. These projects leverage CMU competencies
in bone-tissue engineering, robotics, information technology and microelectromechanical
systems (MEMS). Biomedical engineering projects include: robotically guided
endoscopes; tissue engineered nerve guides; angiogenesis in tissue engineering
bone constructs; implantable telemetry based MEMS bone sensors; coating
of microparticles for controlled drug delivery; computer-aided orthopedic
surgery and context aware computing in medical body monitors.
Robotically
Guided Endoscopes
Robotically guided endoscopes promise to overcome these drawbacks of existing
urological endoscopes. This research project is a collaborative effort
between Carnegie Mellon University and the Children's Hospital of Pittsburgh.
The tip of a robotic endoscope is equipped with sensors that are capable
of identifying the lumen of the urethra or the ureter. Using this sensory
feedback (instead of limited visual information) the endoscope tip can
be continuously adjusted to point in the direction of the lumen. The endoscope
can, therefore be advanced faster, causing less discomfort and a reducing
the potential for tissue injuries associated with endoscopic procedures.
Tissue
Engineered Nerve Guides
ICES researchers are pursuing new strategies to repair nerve injuries,
such as spinal cord injury. This research involves seeding biodegradable
scaffolds with donor cells and growth factors, in this case a nerve guide,
then implanting the tubes to induce and direct the growth of new, healthy
nerve tissue. If successful, this technology will replace existing treatments
for peripheral nerve regeneration including autograft as well as surgical
realignment of the severed ends.
Angiogenesis
in Tissue Engineering Bone Constructs
ICES is also evaluating techniques for implanting biodegradable scaffolds
seeded with cells and/or signaling molecules into bone defect sites to
induce and direct the growth of new healthy bone. Cells that are delivered
with the scaffolds to the defect sites or cells that migrate into the
implanted scaffolds from surrounding healthy tissue need timely access
to a vascular supply. This research is exploring new ways to create vasculature
within scaffolds and defects (angiogenesis) in a timely, organized, and
safe fashion.
Implantable
Telemetry Based MEMS Bone Sensors
Research is also being conducted on bone sensors to detect in vivo bone
stress via a wireless RF interface. The sensor is envisioned to be a 2mm
by 2 mm by 300mm silicon CMOS chip with no external wires. Such a size
is minimally invasive, as it is smaller than typical screws used in setting
bone fractures. Stress is detected using embedded piezoresistive strain
gages made from the CMOS gate polysilicon layer. The chip surface will
be textured with appropriate feature sizing to optimize attachment of
bone tissue. Several kinds of texture will be explored including parallel
ridges, dimpled surfaces and pimpled surfaces, all with varying micron-scale
pitch and depth of the features. Chips will be covered with a titanium
outer layer for biocompatibility. An initial set of experiments to verify
biocompatibility and to measure tissue adherence will be performed by
implanting samples in lab rats. The long-term goal is to integrate implantable
bone sensors with companion development of a tetherless RF interface,
which transmits the stress information and receives power from an external
RF source.
Computer-aided
Orthopedic Surgery
ICES researchers are also pioneering Computer-Aided-Surgery (CAS) techniques.
CAS techniques are emerging methodologies that help surgeons improve outcomes
of their procedures by allowing them to optimally preplan surgical procedures
in a virtual environment. CAS further allows them to precisely execute
their plans during the actual surgery. While CAS is applicable to a broad
range of surgical specialties, CAS is particularly well suited to facilitating
and improving the outcomes of osteotomy procedures for orthopedic surgery.
These procedures are used to reshape a deformed or malaligned bone by
cutting the bone so that the remaining mobile segments can be manipulated
into the desired shape. This is accomplished with the aid of fixation
devices to temporarily stabilize the bone until new bone grows into and
across the osteotomy site.
Coating
of Microparticles for Controlled Drug Delivery
The localized delivery of growth factors and drugs is important in biomedical
applications, in particular for tissue engineering. ICES researchers are,
therefore, working to coat biodegradable polymer microspheres with a protective
membrane which then allows the drug-containing microspheres to become
embedded in tissue-engineered scaffolds.
Context
Aware Computing in Medical Body Monitors
ICES researchers are working collaboratively with Body Media to apply
context aware computing concepts developed in the Laboratory for Interactive
Computing (LINCS) to their medical body monitor. Researchers envision
tapping into the sensing power of Body Media's product and applying it
to create parameters for understanding a user's computing context. Understanding
a users state (i.e., if the user is stressed, nervous, busy or tired)
leads to the development of treatments or therapies that meet the unique
needs associated with each emotional state.
Simulation-Based
Design of Artificial Organs
A
major challenge in the field of artificial organ development is understanding
the behavior of blood flow. ICES researchers in partnership with researchers
from the University of Pittsburgh Medical Center (UPMC) - McGowan Center
for Artificial Organ Development, Texas A&M and the University of
Washington are working on a project to develop multiscale models of blood
flow. Blood flow models will resolve the behavior of blood in complex
geometries - from the organ level to the blood cell level. These models
will form the basis for simulation-based, next-generation artificial organ
design.
The
initial project emphasis is on blood flow and artificial heart devices,
but algorithms and Lagrangian computational methods developed as a result
of this research will provide insight into many other diseases including
hypertension, atherosclerosis and thrombosis, sickle cell anemia and stroke.
This
multidisciplinary project brings together mathematicians, biochemists,
bioengineers, computational fluid dynamicists, computer scientists, hemorheologists,
numerical analysts and transplant surgeons and combines Carnegie Mellon
University's leadership in interdisciplinary computer/computational sciences
with UPMC's world class programs in biological sciences and transplant
surgery.
Artificial
Lungs
ICES is currently conducting an artificial lung optimization project
in collaboration with the Artificial Lung Program and Department of Surgery
at UPMC. ICES researchers are performing mathematical modeling, large-scale
numerical simulations and predictions as well as some component prototyping
whereas researchers at UPMC carry out the in-vitro and animal experimentation.
Numerical predictions and optimization enables the development of superior
Intravenous Membrane Oxygenator (IMO) devices, known by the lay public
as artificial lungs.
The
goal of this research is to develop a simulation-based methodology for
artificial lung and blood-wetted organ design. The project requires the
creation of mathematical models, computational tools and validation by
in-vitro experimentation. If successful, optimal design methodologies
will lead to the design of artificial organs with improved gas exchange
capability, minimal risk of blood trauma and thrombosis. The objective
of this research project is to develop methods of improving artificial
organ function, greatly improving a recipient's quality of life.
Aortic
Aneurysms
Abdominal
Aortic Aneurysms (AAAs) are localized balloon-shaped expansions commonly
found in the infrarenal segment of the abdominal aorta, between the renal
arteries and the iliac bifurcation. Abdominal aortic aneurysm rupture
is the 15th leading cause of death in the United States, affecting patients
over 55 years of age, typically 2-4% of elderly males. Typical treatment
consisting of conservative or surgical management is based on the surgeon's
estimation of the risk of rupture vs. mortality and morbidity during surgery
combined with the patient's life expectancy. Aneurysm size is often used
as the primary indicator of potential rupture by measuring the AAA's maximum
diameter. Elective Surgical resection is justified when this diameter
exceeds the critical value of 5 cm. It is well known, however, that not
all large aneurysms rupture and that aneurysms with a maximum diameter
less than the critical value may. Therefore, the criterion results unreliable
for the individual patient and there is need for a better assessment of
rupture potential.
ICES
is assessing the rupture potential of AAA's using computational modeling
and simulation, which uses large-scale numerical simulations and modeling
based on physiologically realistic measurement obtained during patient
diagnosis. The objective of this research is to develop a non-invasive
technique for the assessment of aneurysm rupture by integrating the mechanical
properties of the artery wall and physiologic blood flow conditions into
a unique computational model of aneurysm hemodynamics. This research is
being performed in collaboration with Vascular Surgery and Vascular Biomechanics
Research Lab of the Section of Vascular Surgery.
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