Biomedical Engineering Reference
In-Depth Information
made with respect to their efficiency, performance, versatility, and biocompatibil-
ity. Moreover, effective drug-delivery applications may require a device with
autonomous self-adaptive properties with the ability to interact with other motors
in order to deliver heavy therapeutic cargoes. As the sophistication of these
nanomachines becomes significant, their potential applications in drug delivery,
cell sorting, nanosugery, biopsy, and bioassays become considerable. The advent of
acoustically driven nanomachines opens up the prospect of controlling the
micromotors harmlessly albeit in a deeply penetrative fashion permitting the
navigation through physiological fluids and performing targeted therapies in places
with reduced accessibility.
Other nanoscale devices, such as nanoneedles and nanotweezers, for controlled
fluid handling and cell interrogation have attracted a large amount of interest.
Intracellular injections and electrophysiological measurements rely on nanodevices
usually based on atomic force microscope (AFM) cantilevers with electrically or
mechanically interfaced silicon or carbon-nanotube tips [
63
]. Nanoneedles, pro-
duced by etching a silicon AFM tip by means of a focused ion beam, can pierce
membranes and reach the cell nucleus with negligible deformation and damage
[
64
]. Moreover, multiwall carbon nanotubes can be connected to AFM tips and
used to deliver molecules into the cell [
65
]. Recently, a multifunctional endoscope-
like device was developed for prolonged intracellular probing at the single-
organelle level, without metabolically disturbing the cell. Using individual carbon
nanotubes, the endoscopes can transport fluid, record cellular signaling, can be
manipulated magnetically, and allow for intracellular fingerprinting using surface-
enhanced Raman spectroscopy (SERS) [
66
].
1.2.3 Tissue Engineering
Regenerative medicine is impacted by the introduction of biocompatible
nanostructured scaffolds enabling the replacement, regeneration, and repair of
impaired tissues, such as cardiac, bone, cartilage, skin, bladder, nervous, and
vascular tissues [
21
]. These nanomaterials improve the biological properties of
the cell by enhancing cell adhesion, motility, and differentiation [
67
,
68
]. It is
imperative to develop nanoscaffolds that mimic the three-dimensional microenvi-
ronment of the cell in order to permit specific cell interactions and adequate cell
behavior. The production of nanofibers by electrospinning offers great flexibility
over the scaffold's properties and geometry [
69
]. Moreover, complementary
functionalities can be brought about by chemical conjugation of signaling
molecules or protein coatings improving tissue engineering therapies and regener-
ative medicine.
