Biomedical Engineering Reference
In-Depth Information
(2) Selective capturing of toxin/pathogen
(1) Injection of magnetic
capturing agent
(3) Magnetic separation
FIGURE 21.7
Schematic depiction of the process of pathogen removal from the
blood using nanomagnets
[16].
21.4.4.7 Nanomagnets Remove Pathogens from Blood
Demonstrating a novel use of nanomagnets, researchers in Switzerland have rapidly and selectively
removed heavy metal ions, overdosed steroid drugs, and proteins from human blood. Rapidly acces-
sible surface of the nanomagnets enables efficient adsorption in contrast to other blood purification
techniques available on the market (
Figure 21.7
).
21.4.4.8 Nanocrystalline Silver
With most applications of nanotechnology in medicine still under development, nanocrystalline silver
is already being used as an antimicrobial agent in treatment of wounds
[17]
. Silver works in a number
of ways to disrupt critical functions in a microorganism. It has a high affinity for negatively charged
side groups on biological molecules such as sulphydryl, carboxyl, phosphate, and other charged
groups distributed throughout microbial cells. Silver attacks multiple sites within the cell to deac-
tivate critical physiological functions such as cell wall synthesis, membrane transport, nucleic acid
(RNA and DNA) synthesis and translation, protein folding and function, and electron transport. For
certain bacteria, as little as one part per billion of silver may be effective in preventing cell growth
[18]
. Silver antimicrobial nanotechnology is effective against pathogens associated with biofilms
including
E. coli
,
Streptococcus pneumoniae
,
S. pneumoniae
,
Streptococcus aureus
, and
Aspergillus
niger
[19]
. Local nanoscale characterization of cellular ultrastructure and functional properties is an
important focus for probing cariogenic nature of oral microbes. The development of resistance to
antimicrobial silver would be extremely rare because an organism would have to undergo simultane-
ous mutations in every critical function within a single generation to escape silver's influence. Silver
