Biomedical Engineering Reference
In-Depth Information
12.2.3.4 Other Metallic Nanomaterials
Besides the most commonly used gold nanomaterials, iron oxide nanomaterials, and QDs, a series
of other metallic nanomaterials have fascinated scientists due to their potential utilization in engi-
neering and biomedical sciences.
It is believed that platinum nanoparticles can release platinum ions via surface oxidation, which
can contribute to their anticancerous properties.
61
Silver nanoparticles are well known for their
antimicrobial properties.
62
However, Asharani et al.
45
found that both silver (5-35 nm) and plati-
num nanoparticles (3-10 nm) induced a concentration-dependent drop in heart rate when incubated
with zebrafish embryos. Silver nanoparticles also induced other significant phenotypic changes,
including pericardial effusion, abnormal cardiac morphology, and circulatory defects.
45
In another
study, zebrafish was found to develop cardiac malformations when treated with 0.07-0.71 nM silver
nanoparticles, with the highest occurrences at 0.66 nM.
63
Among all types of observed deformities,
cardiac malfunctions occurred at the third highest rate.
Yttrium oxide (Y
2
O
3
), and zinc oxide (ZnO) nanoparticles were found to induce a pronounced
inflammatory response in HAECs when the concentration exceeded a threshold of 10 μg/mL, as
indicated by the elevated mRNA and protein levels of ICAM-1, IL-8, and MCP-1.
49
In addition, ZnO
nanoparticles were found to be cytotoxic and led to considerable cell death at 50 μg/mL. Similarly,
Sun et al.
50
found that several metallic nanoparticles, including ZnO nanoparticles, produced cyto-
toxicity in a concentration- and time-dependent manner, and elicited a permeability and inflam-
mation response in HCMECs. The threshold concentration to initiate an inflammatory response
was 5 μg/mL for ZnO and CuO nanoparticles and 100 μg/mL for MgO nanoparticles. On the other
hand, the authors also found that aluminum oxide (Al
2
O
3
) nanoparticles did not show significant
effects on cytotoxic, permeability, and inflammation responses in HCMECs at any of the concentra-
tions tested (12-24 h and 0.001-100 μg /m L).
50
Cerium dioxide (CeO
2
) nanoparticles were found to be relatively less toxic to cardiovascular
systems in several
in vitro
and
in vivo
studies. Kennedy et al.
64
found that CeO
2
particles elic-
ited no inflammation responses at low concentrations and a weak response from 10 to 50 μg/mL
after 4 h of incubation with HAECs. Niu et al.
65
assessed the effects of CeO
2
nanoparticles on
cardiac function and remodeling as well as endoplasmic reticulum (ER) stress responses in this
murine model of cardiomyopathy. It was found that CeO
2
nanoparticles protected against the
progression of cardiac dysfunction and the remodeling by attenuation of myocardial oxidative
stress, ER stress, and inflammatory processes, probably through their autoregenerative, antioxi-
dant properties.
12.3 CONCLUSIONS AND PERSPECTIVES
The development of various nanomaterials may be expected to lead to revolutionary therapeutic
approaches. However, the pharmacological and toxicological profiles of nanomaterials within the
cardiovascular system are still limited, and the underlying mechanisms are yet to be clarified. A few
points may need to be paid attention to in future studies. The models used to evaluate cardiovascular
toxicity need to be standardized. To date, various models have been used in different experiments
without criteria for general selection, which may affect the comparison of the results from differ-
ent researchers and the generation of conclusions. In
in vivo
studies, different species of animals
were used, including mouse, rat, and rabbit, while cells of various origins were tested in the
in vitro
studies, such as HAECs, HUVECs, HDMECs, HCMECs, and HCMs. The interpretation of the
data from a composite system needs to be performed with caution. Nanomaterials are often surface
modified to improve their surface properties and consequently improve their biocompatibility with
the human body and dispersity in the aqueous solution. The toxicity data from such systems need to
be carefully studied to reveal which material is indeed responsible for adverse effects and provide
a chance for improvement.
