Nanoparticles: Cute little killers

by Vlad Georgescu, 19.08.2009

For the first time, clinicians have succeeded in proving that inhaled nanoparticles can cause severe damage to the lungs in humans and lead to the death of patients. The publication is likely to present new challenges for environmental physicians worldwide.

For the doctors at Beijing Chaoyang Hospital, the women were conspicuous from the very beginning. Shortness of breath, pleural effusion and pericardial effusion determined the clinical picture, even though the patients admitted between January 2007 and April 2008 were young and otherwise in excellent health. They had never smoked, and the medical history did not seem to indicate any particular risks. However, the seven women had undergone a veritable odyssey in terms of therapy before being admitted to the Chinese elite clinic: From antibiotics to active substances against tuberculosis, doctors at other hospitals had tried to cure the curious malaise - in vain. The advance of the pleural outflow increased to such an extent that the doctors called in the national epidemic authority - and finally found what they were looking for by means of an exact examination of the women's living conditions.

According to the doctors, tiny polyacrylate nanoparticles inhaled by the women at their joint workplace caused the accident in the patients' bodies. Despite all efforts of the Chinese doctors, two women did not survive the attack of the nanoparticles. Their deaths, so much seems to be certain already, will possibly trigger a global turnaround in the risk assessment of nanotechnology.

Never before have scientists succeeded in proving the causal relationship between inhaled nanoparticles and their toxic side effects in humans. For years, animal experiments have shown that the tiny atomic particles can sometimes attack the kidneys and liver as well as the lungs. However, damaging effects in exposed people have been suspected to date, but have not been clinically proven.

The Beijing Nano Case ends the era of the supposed safety of a technology that is still one of the most promising of the 21st century. Unusually openly, the Chinese are publishing what has frightened doctors in Beijing: Inhaled nanoparticles appear to be able to attack the internal organs and penetrate deep into the cells of the organism. If you read the study in the original, you will inevitably find parallels to Michael Crichton's bestseller "Prey", in which nanoparticles infect humans - but unlike Crichton, the events in Beijing are reality.

Global rethinking of security seems necessary

For example, the inhalation of the nano-polyacrylates at the workplace over a period of five months led to the development of pulmonary fibrosis in the women concerned, in addition to the ailments already mentioned. The researchers also found polyacrylates with a size of 30 nanometres in the karyoplasm and cytoplasm of the lung tissue of their patients. But that is not all. The nanoparticles also adhered to the membrane of the red blood cells - which was also demonstrated for the first time in a clinical setting using real patient data. It is the small size of the particles that makes it so difficult for physicians to fight against this. "Patients can develop pulmonary fibrosis that is resistant to several forms of therapy," warns study author Yuguo Song in the European Respiratory Journal (ERJ), where the study appeared on 19 August 2009. According to Song, there is one aspect in particular that is considered to be particularly sensitive: the pathogenic polyacrylates served as a kind of nanocarrier for inks - which were used in the printing industry as coatings of particular industrial value. In fact, the range of applications for nanoparticles is enormous - the global market is expected to reach around 200 billion euros in 2010 alone. The Chinese results will possibly lead to changes in the general conditions - in this country as well.

 However, many scientists are still taking a relaxed view and are focusing primarily on the therapeutic potential. For example, a clinical research group at Berlin's Charité Hospital is developing a new class of magnetic nanoparticles as contrast media for magnetic resonance imaging. As recently as September 2008, the special properties of the tiny particles even excited the DFG: "The novel particles are unusually small and have surface coatings that allow the particles to reach the location of interest in the body in a particularly targeted manner". After the Beijing study, it will be necessary to look at precisely this in a different light.

Translated Version - Original here