Biomedical Engineering Reference
In-Depth Information
to construct highly stable sensing structures, which are small enough to be implanted in
the body, distributed widely in the environment, configured as high-density arrays, or
coupled to modern information systems, offers exciting new horizons in the information
revolution by furnishing our information and telecommunication systems with sophisti-
cated “senses.”
23.2.3
Optical Nucleic Acid Sensors
Optical nucleic acid sensors are another emerging technology that researchers with the
University of Toronto at Mississauga, under the direction of Ulrich Krull (personal com-
munication, 2005), believe will advance the role that biosensors play in our daily lives. The
detection of nucleic acids is now used in many applications such as screening of genomes
for mutations, detection and identification of bacteria and viruses, and efficient searching
of compound libraries for potential therapeutic agents. Microarrays and multiplexed
bead-based assays represent technologies that are suitable for large-scale screening, but
are not ideally suited for practical applications involving a limited set of genomic targets.
Enter the world of biosensors, where quantitative analysis can be achieved and the devices
can concurrently address five practical priorities, namely reproducibility, reusability,
speed of response, selectivity, and sensitivity. Novel configurations and applications in the
development of optical nucleic acid sensors will continue. One can anticipate interest in a
variety of areas including quantitative high-throughput (HT) nucleic-acid biosensors sys-
tems, development of spatially resolved biorecognition surfaces, and further development
of generic nanosensors.
A quantitative HT nucleic-acid-biosensor diagnostic system will permit rapid detection
of well-defined target nucleic acids in cell suspensions and solid tissues. New micro-
biosensors placed within microfluidic cartridges shall, with further refinement of surface
chemistries and development of accelerated-target-delivery mechanisms, rapidly (in sec-
onds) detect and determine low-copy number targets (10 3 ). Such systems will need to be
complemented by new concepts in automated sampling, sample processing, and automa-
tion where throughput of ~1000 determinations per hour will be achieved.
Furthermore, new quantitative approaches to the development of spatially resolved
biorecognition surfaces that would be suitable for screening and for SNP recognition will
be developed. This requires improved methods of immobilization to improve confidence in
the reliability of signals, as well as the use of smaller arrays to realize the full potential of
quantitative microfluidics. Finally, the development of generic nanosensors for the direct,
real-time determination of select nucleic acid levels in microenvironments with the ultimate
aim of time-resolved intracellular determination of RNA levels is another direction. A sig-
nificant leap in technology would be to measure and multiplex signals from inTrace.
23.2.4
Nanostructured Organic Biological Matrices
Recently, developed sensor systems that are based on nanostructured organic-biological
matrices appear to have made a significant impact on the development of intelligent
biosensors for monitoring gas and liquid with the potential for greatly effecting health
care and environment control. According to Claudio Nicolini (personal communication,
2005), and his fellow researchers with the Nanoworld Institute at the University of Genoa,
there appears to be four promising directions that are closely tied to industrial application
of nanostructured organic matrices.
A unique opportunity exists for functionalized POAS and the PDMA-MWNT nanocom-
posites, which may lead in the near future to a spontaneous reversible sensor for acid
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