The tests were performed using a Langendorff heart, which is an isolated rodent heart flushed with a nutrient solution in place of blood, and the results published in the peer review journal ACS Nano.
Using the so-called Langendorff heart, the scientists exposed it to a series of commonly used artificial nanoparticles, and stated that the heart reacted to certain types of particles with an increased heart rate, cardiac arrhythmia and modified ECG values that are typical for heart disease.
The nanoparticles used to test were carbon black, spark-generated carbon, titanium dioxide and silicon dioxide.
Other studies suggest the safety of these materials
However studies carried out by the US Food and Drug Administration showed that nanomaterials such as titanium dioxide were safe for use in products.
Titanium dioxide is one of the materials used as a UV blocker in sunscreens due to its large surface area in comparison to its volume.
The FDA deemed the material safe and even said it went a long way to protect against skin cancer, a claim that was supported by the Personal Care Products Council.
With regards to sunscreen, the studies carried out presume that the nanoparticles have been absorbed into the bloodstream and thus flushed through the heart, however many studies suggest the case for safe, non-penetrative topical sunscreens that contain nanoparticles.
Reported heart rate increase
The tests carried out by Andreas Stampfl, first author of the study, and his team state that the exposure to the nanopatricles tested led to an increase in the heart rate of up to 15 per cent with altered ECG values that did not normalise, even after the nanoparticle exposure was ended.
With their enhanced Langendorff heart, the researchers claim to have developed for the first time a measurement setup that can be used to analyse the effects of nanoparticles on a complete, intact organ without being influenced by the reactions of other organs.
"It [the heart] has its own impulse generator, the sinus node, enabling it to function outside the body for several hours," said Stampfl. "Additionally, changes in the heart function can be clearly recognized using the heart rate and ECG chart."
Director of the Institute of Hydrochemistry at the TU Muenchen, Reinhard Nießner, one of the scientists involved, also commented: "We now have a model for a superior organ that can be used to test the influence of artificial nanoparticles."
"The next thing we want to do is to find out why some nanoparticles influence the heart function, while others do not influence the heart at all."
The scientists are planning further studies to examine the surfaces of different types of nanoparticles and their interactions with the cells of the cardiac wall.
Journal Reference
Andreas Stampfl, Melanie Maier, Roman Radykewicz, Peter Reitmeir, Martin Göttlicher, Reinhard Niessner.Langendorff Heart: A Model System To Study Cardiovascular Effects of Engineered Nanoparticles.ACS Nano, 2011; 5 (7): 5345 DOI: 10.1021/nn200801c