Biomedical Engineering Reference
In-Depth Information
Silver nanoparticles have been extensively used in nanocomposite films to
avoid attack from a broad spectrum of microorganisms and to reduce infec-
tions.
293
Silver nanoparticles evenly dissipated in biodegradable polymers
would allow timed release of the silver species in a controlled manner allowing
for antibacterial action over an extended period. There are recent reports on
the use of silver nanoparticles as antimicrobials in PLGA matrix nanocompos-
ites.
294,295
These studies indicated antibacterial effect of electrospun biodegrad-
able fibers containing silver nanoparticles over more than 20 days.
296
Presence
of dispersed metal nanoparticles enhanced the thermal conductivity of the
nanocomposites that can speed up the degradation of the polymeric matrix.
297
Additionally, low concentrations of silver nanoparticles induced surface mor-
phological changes in the polymer matrix that altered surface nanocomposite
wettability and roughness which influenced bacterial adhesion on the nanocom-
posite surface.
298,299
The contact angle increases with >5% silver content that
causes hydrophobic behavior that is associated with increase in surface rough-
ness that is induced by the presence of silver nanoparticles. Various factors such
as surface preparation, texture, chemical, and physical configuration that can
influence biomaterial bacteria adherence affect the contact angle.
300,301
6.6 CELL REPAIR
Cell repair involves manipulations of cell organelles and molecules that are
similar to the same tasks that living systems already prove possible.
302
Cells
are accessed by inserting needles without killing them or by using molecular
machines.
303
Specific biochemical reactions show that molecular systems inter-
act with other molecules as they come in contact, thereby building and rebuild-
ing every molecule in a cell or expelling disassembled damaged molecules.
Actively growing viable cells utilize built-in molecular systems to manufacture
and assemble the various components of a cell. Following these built-in mecha-
nisms to repair a cell, nanomachine-based systems that are able to enter cells,
sense differences from healthy or sick ones, can be built to make modifications
to restore sick cells into their healthy state. These nanomachines will have to be
biocompatible and nonforeign to the cell or to the organism in order that these
will not be sequestered before those are able to perform their designated task.
The applications of nanomachines for cell repair are enormous. Smaller than
the sizes of the various cell organelles, nanomachines can be engineered and
designed to carry out various functions inside a cell. They can be designed for
specific functions or they can be modified for multiple functions. As they go
in and out of the cell membranes, travel through tissue and organs, they can
correct molecular damages, deliver specific chemicals, or augment and cure
deficiencies. In order to be able to wade their way into the cells, tissues, and
organs of interest, the nanomachines need nanocomputers for guidance. These
nanocomputers will direct and detect the nanomachines as they examine, repair,
rebuild, or disassemble damaged molecular structures inside the cells. The
