The succesful application of...
manufactured nanomaterials in nano-enabled products may lead to emissions in the environment, with an incomplete hazard and risk assessment. The ‘invasion’ of new manufactured nanomaterials and nano-enabled products into nearly every aspect of modern life has raised concerns and increased calls for the application of the precautionary principle to safeguard the health of humans and the environment.
When released in the workplace or the environment nanomaterials may be dangerous. The skin, gastrointestinal tract, nasal olfactory structures and the eyes are the major portals through which nanoparticles can enter the body as a result of occupational or environmental exposures.
After exposure, nanoparticles can travel through the blood and lymph circulating system reaching distant organs including the cardiovascular system and brain.,
Of primary concern in occupational settings are inhalation of nanoparticles and skin exposure.
So far, healthy skin has shown little penetration potential, however, there are several studies that illustrate that the condition of the skin (barrier integrity, anatomic structure, skin diseases, etc.) may influence uptake. Inhalation is the most relevant exposure route of manufactured nanomaterials and the lungs and pleura are the primary targets for adverse effects. It is possible for the inhaled nanoparticles to penetrate the lungs and deposit themselves in the respiratory system. It is believed that inhaled nanoparticles have reduced clearance from lungs relative to larger particles and can have increased transfer into the blood stream., Inhaled ambient ultra-fine particles can be found in the heart, bone marrow, liver, kidney and even the central nervous system.
When nanomaterials have entered the human body they can take part in reactions within cells, with the potential to exhibit adverse health effects. The primary toxicity concern of nanoparticles is the damage that is caused by free radical generation, which can provoke intense oxidative stress, inflammation and cell damage in the body., Oxidative stress is defined as an imbalance between oxidants and antioxidants inside cells, in lung lining fluid or tissue fluid.
Preliminary data indicates that acute toxicity and systemic effects on different organ systems, including the immune, inflammatory and cardiovascular systems may occur.
Furthermore, genotoxicity and possible carcinogenesis and teratogenicity may occur, but no data on these latter endpoints is available yet.
The form of nanomaterials is an important issue in hazard and risk assessment. Carbon nanotubes (CNT) were shown to be able to induce asbestos-like alterations in the mesothelium of the mouse peritoneal cavity and increase the likelihood of mesotheliomas in sensitive mouse strains. Long CNTs may give an acute inflammation leading to progressive fibrosis of the pleura, while this is not the case for short CNTs.
In conclusion, much is still unknown, but it is clear that nanomaterials are likely to interfere with cellular organization and affect biological functions in ways that cannot be deduced from previous experience with macro- or micro particles. Therefore, there is an urgent need for improved characterization and reliable toxicity screening tools (all still very limited) to elucidate health and environmental impacts, as it has been shown that the ones available (targeted to bulk chemicals and substances) might not be suitable for the assessment of nano-risks. Relevant in this respect is to further operationalize the paradigm change in risk assessment from a mass-based approach towards a particles’ number based approach.
Potential effects of inhaled nanoparticles
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A promising field...
of nanotechnologies is Nanomedicine, which has created a myriad of new opportunities for advancing medical applications and disease treatment in human health care. Nanomedicine could be defined as the science and technology of diagnosing, treating and preventing disease and traumatic injury, of relieving pain and of preserving and improving human health, using nanomaterials and/or nanotechnological techniques and devices.
The fundamental concept of nanomedicine in influenced by the visionary idea that nanorobots and related machines could be designed, manufactured, and introduced into the human body to perform cellular repairs at the molecular level. Today this idea has moved away from the nanorobots idea towards passive and active targeted medicine, which has branched out in many different directions, each of them promising to bring enormous benefits in the research and practice of medicine. Some of the application fields of nanomedicine include drug delivery, gene delivery, bio-imaging and detection, cardiac therapy, dental care, cancer therapy, etc.
A key field for nanomedicine is the early detection, diagnostics, prognostics and targeted cancer treatments. While the potential benefits of nanotechnologies in this field appear to be overwhelming and with an enormous impact on the quality of human life, the way from research to practice is long. This means that many promising applications are not yet available for the general public to use..
Nanotechnologies in oncology encompass many applications such as:
Molecular imaging and detection:
Molecular imaging of live cells and whole organisms is an important tool for studying cancer biology and determining the efficacy of tumor therapies.
Improved therapeutic index of drugs through their more efficient delivery to the biological targets and reduced toxicity with appropriate application of nanotechnologies.
New drug therapies:
Safer cancer drugs characterized by adequate drug concentration in the body to allow for an effective dose at the tumor site.
Nanoparticles and cancer treatment
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