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THE
BIOMEDICAL MICRO
AND NANO
SYSTEMS LABORATORY
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| 1.
Implantable Wireless Microsystems for Diagnosis
and Management of Glaucoma |
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Collaborators |
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Drs.
Jay MacLaren and Doug Johnson, Mayo Clinic and J.
D. Brown of the University of Minnesota. |
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Graduate
students: |
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Woohyek
Choi and Tingrui Pan |
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Support:
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NSF |
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Synopsis |
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This
project is to develop an implantable microsystem
for detection and treatment of Glaucoma. To detect
pressure variation of the eye, the CMOS IC and Piezoresistive
sensor are being developed. CMOS chip is powered
by inductive coupling. With load modulation technique,
detected pressure signal can be transferred to the
external system. In order to vary the intra-ocular
pressure (IOP) set point over a period of time for
the treatment, a micromachined check-valve with
a wireless electrochemical release mechanism is
being developed to substitute the current glaucoma
drainage device (GDD). The ability to remotely detect
the pressure and change the set point with implanted
microsystem provides more accuracy and flexibility
in managing Glaucoma |
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| 2.
Hydrogel-Based Microsystems for Glucose Sensing
and Insulin Delivery |
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Collaborators |
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Prof. Ron. Siegel (Pharmaceutics UMN) |
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Graduate
students: |
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Alex Gu (Pharmaceutics), Ming Lei
(ECE) |
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Post Doc: Antonio Baldi |
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Support:
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Army, NIH |
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Synopsis |
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:In
this project we are exploring the potential of the
integration of environmentally sensitive hydrogels
with MEMS. These hydrogels are tangled networks
of cross-linked polymer chains that manifest a reversible
and abrupt phase transition in response to the changes
in environmental factors such as glucose concentration,
pH, electric field, temperature, and light. This
transition results in an abrupt volume change (swelling
or shrinking) that can be as large as 1000 fold.
Because of this property, hydrogels are attractive
candidates as components of microsensors and microactuators
operating in aqueous media such as body fluids.
For example, we have developed various microfluidic
controllers using a glucose- and pH- sensitive hydrogel
(see references below). Currently we are developing
an implantable transponder for wireless glucose
measurement. |
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| 3.
Wireless Recording of Neural Ensembles in Awake
Behaving Rats |
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Collaborators |
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Profs Redish (Neuroscience) and Art
Erdman (Mechanical Engineering) |
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Graduate
students: |
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Rahul Venkateswaran (ME), and Jayant
Parthasarathy (ECE) |
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Support:
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McKnight Endowment Fund for Neuroscience |
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Synopsis |
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This
30 month project, beginning Sept 2002, involves
designing a wireless transceiver capable of recording
neural ensembles from the rats brain. The Mechanical
Engineering challenges are in the design and assembly
of micro-motors for accurate control of electrode
depth in the brain. The Electrical Engineering challenges
are in designing circuitry for transmission of multi-channel,
very high data-rate signals with limited circuit
board area. Another challenge is in the design of
effective dc-offest cancellation circuitry. The
project is amongst the first to be attempted of
its kind and on completion hopes to immensely aid
neuroscientists to better interpret the behavioral
pattern of rats. |
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| 4.
Micromechanical Engineering of Connectivity in Living
Neural Networks |
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Collaborators |
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Profs Odde (BME) |
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Graduate
students: |
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Mauris De Silva (MSE) |
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Post Doc: Antonio Baldi |
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Support:
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NSF |
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Synopsis |
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:Recent
studies by Odde et al have shown the effectiveness
of mechanical forces in eliciting neurites outgrowth
de novo from neurons in culture. These were performed
on single cells by applying forces with a glass
microneedle or magnetic beads which were allowed
to adhere to the cells. In this project we have
developed a microtool to use this approach on arrayed
neuronal cells in order to engineer large living
neural networks having defined connectivity. It
consists of an array of microposts that can be matched
to an array of cells and can be moved in close proximity
to the surface of the culture dish. The microtool
will be used to elicit neurite outgrowth from all
the neurons in the array simultaneously, thus creating
the connections of the network in a very efficient
way. |
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| 5.
Biomolecular Crystallization Microarray |
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Collaborators |
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Prof. Barocas (BME) |
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Graduate
students: |
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Shramik Sengupta (BME) |
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Support:
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NIH |
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Synopsis |
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:The
goal of this research project is to design and fabricate
micro-scale reactors and flow-control systems in
order to perform controlled crystallization of protein
molecules. Milli-scale prototypes of a novel type
of flow-sensor have been fabricated and are being
characterized. Micro-scale versions of this device
(capable of measuring flow-rates of pico-liters
per second) will be shortly fabricated. In addition,
we plan to develop mathematical models to model
the mixing of water and protein and salt solutions
in micro-reactors of various shapes and sizes. This
should yield insights for designing a "good" reactor
that will maximize mixing but minimize hotspots
for precipitation. We also plan to specify the optimal
feed profile of protein and salt solutions (with
respect to time) by coupling available kinetic models
for crystallization of proteins with various mixing
and operating models of the reactors. |
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