Biomedical Engineering Reference
In-Depth Information
systems. Recent results from a research project involving industry and a
university point to the use of nanoparticles in lubricants to enhance
tribological properties such as load carrying capacity, wear resistance, and
friction reduction between moving mechanical components. Such results are
encouraging for improving heat
transfer rates in automotive systems
through the use of nanofluids.
10.4.5 Applications in biomedicine
Endeavors concerning the development of integrated nanodrug delivery
systems can enable convenient monitoring and controlling target-cell
responses to pharmaceutical stimuli, understanding biological cell activities,
or creating new drug development processes. While conventional drug
delivery is characterized by the 'high-and-low' phenomenon, microdevices
facilitate precise drug delivery by both implanted and transdermal
techniques. When a drug is dispensed conventionally, the drug concentration
in the blood will increase, peak, and then drop as the drug is metabolized,
and the cycle is repeated for each drug dose. In case of nanodrug delivery
systems, controlled drug release can take place over an extended period of
time. Thus, the desired drug concentration will be sustained within the
therapeutic window as required. A nanodrug supply system (bio-MEMS)
was studied by Kleinstreuer et al. (2008) where the principal concern was the
conditions for delivering uniform concentrations at the microchannel exit of
the supplied nanodrugs. A heat flux, which depends on the levels of nanofluid
and purging fluid velocity, was added to ascertain that drug delivery to the
living cells occurred at an optimal temperature.
A new initiative takes advantage of several properties of certain
nanofluids for use in cancer imaging and drug delivery. This initiative
involves the use of iron-based nanoparticles as delivery vehicles for drugs or
radiation in cancer patients. Magnetic nanofluids are to be used to guide
particles through the bloodstream to a tumor using magnets. This will allow
doctors to deliver high local doses of drugs or radiation without damaging
nearby healthy tissue, which is a significant side effect of traditional cancer
treatment methods. A nanofluid containing magnetic nanoparticles also acts
as a super-paramagnetic fluid which, in an alternating electromagnetic field,
absorbs energy producing controllable hyperthermia. By enhancing
chemotherapeutic efficacy, hyperthermia is able to produce a preferential
radiation effect on malignant cells (Chiang et al., 2007).
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10.5 The rheology of nanofluids
Although some articles have been published on the viscosity of nanofluids,
very limited data have been reported analyzing the rheological behavior of
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