50,054 research outputs found
Design and Optimizing of On-Chip Kinesin Substrates for Molecular Communication
Lab-on-chip devices and point-of-care diagnostic chip devices are composed of
many different components such as nanosensors that must be able to communicate
with other components within the device. Molecular communication is a promising
solution for on-chip communication. In particular, kinesin driven microtubule
(MT) motility is an effective means of transferring information particles from
one component to another. However, finding an optimal shape for these channels
can be challenging. In this paper we derive a mathematical optimization model
that can be used to find the optimal channel shape and dimensions for any
transmission period. We derive three specific models for the rectangular
channels, regular polygonal channels, and regular polygonal ring channels. We
show that the optimal channel shapes are the square-shaped channel for the
rectangular channel, and circular-shaped channel for the other classes of
shapes. Finally, we show that among all 2 dimensional shapes the optimal design
choice that maximizes information rate is the circular-shaped channel.Comment: accepted for publication in IEEE Transactions on Nanotechnolog
Molecular Communication Using Brownian Motion with Drift
Inspired by biological communication systems, molecular communication has
been proposed as a viable scheme to communicate between nano-sized devices
separated by a very short distance. Here, molecules are released by the
transmitter into the medium, which are then sensed by the receiver. This paper
develops a preliminary version of such a communication system focusing on the
release of either one or two molecules into a fluid medium with drift. We
analyze the mutual information between transmitter and the receiver when
information is encoded in the time of release of the molecule. Simplifying
assumptions are required in order to calculate the mutual information, and
theoretical results are provided to show that these calculations are upper
bounds on the true mutual information. Furthermore, optimized degree
distributions are provided, which suggest transmission strategies for a variety
of drift velocities.Comment: 20 pages, 7 figures, Accepted for publication in IEEE Trans. on
NanoBioscienc
Distributed Control of Microscopic Robots in Biomedical Applications
Current developments in molecular electronics, motors and chemical sensors
could enable constructing large numbers of devices able to sense, compute and
act in micron-scale environments. Such microscopic machines, of sizes
comparable to bacteria, could simultaneously monitor entire populations of
cells individually in vivo. This paper reviews plausible capabilities for
microscopic robots and the physical constraints due to operation in fluids at
low Reynolds number, diffusion-limited sensing and thermal noise from Brownian
motion. Simple distributed controls are then presented in the context of
prototypical biomedical tasks, which require control decisions on millisecond
time scales. The resulting behaviors illustrate trade-offs among speed,
accuracy and resource use. A specific example is monitoring for patterns of
chemicals in a flowing fluid released at chemically distinctive sites.
Information collected from a large number of such devices allows estimating
properties of cell-sized chemical sources in a macroscopic volume. The
microscopic devices moving with the fluid flow in small blood vessels can
detect chemicals released by tissues in response to localized injury or
infection. We find the devices can readily discriminate a single cell-sized
chemical source from the background chemical concentration, providing
high-resolution sensing in both time and space. By contrast, such a source
would be difficult to distinguish from background when diluted throughout the
blood volume as obtained with a blood sample
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