Nanotechnology deals with the study of man-made materials engineered on a molecular and atomic scale; structures studied on this scale are referred to as nanostructures, varying in size from 1-100 nanometres, only slightly larger than the scale of atoms and molecules (which are typically 0.1-1 nanometres in diameter).The term nanoparticles refers to particles on this scale;
A nanometre (nm), the unit of measurement used for structures on the atomic scale, is one billionth of a metre;
Normal office paper is about 100,000 nanometres thick;
One nanometre is about one fifty thousandth the width of a human hair, and about a million times smaller than a pinhead;
Nanostructures have a wide variety of applications, including medicine, drug delivery, biological imaging, materials, building, structural engineering and energy generation (more on medical applications below).
What applications do nanoparticles have in medicine?
Drug delivery – nanoparticles can be used to target drugs to specific cells in the body and to directly enter cells without damaging the cell membrane; scientists at MIT recently demonstrated this with gold nanoparticles coated in alternating molecular ‘stripes’;
A class of nanoparticles known as ‘quantum dots’, which can emit different types of light depending on their size, have wide applications in biotechnology for cell labelling and bioimaging, including imaging in cancer studies;
Nanoparticles could also be used to treat cancer directly by targeting them to cancer sites and using light or magnetism to heat them, thereby destroying the cancer cells – although this kind of treatment remains at an early stage;
Nanotechnology can help with the development of injectable drugs by reducing particle size, producing drugs which are more rapidly taken up and easier to administer – there is also scope for developing improved implantable drug delivery systems, proving a more consistent delivery of the drug into the body;
Nanomaterials can potentially have roles in tissue engineering, in the production of artificial ‘scaffolds’ for the re-growing of tissues and organs specifically tailored to the patient, as well as implants and materials used in artificial joints, which are more hard-wearing and longer-lasting.
What are their effects? What are the potential risks/health impacts?
Depending on their chemistry and structure, nanoparticles can interact with cells either directly, by direct uptake into the cell; or indirectly, whereby particles interact with the cell membrane and trigger further cell signalling mechanisms within the cell. However, not all nanoparticles behave in the same way;
These properties can be utilised to produce particular outcomes – for example by promoting drug delivery across the cell membrane, or by promoting specific reactions within cells;
This raises the possibility of unforeseen effects – for example, nanoparticles small enough to cross the cell membrane could interact with DNA and cause damage, and potentially diseases such as cancer;
Due to their small size, nanoparticles may be capable of crossing barriers that other types of particle are not – most notably the blood-brain barrier, which normally provides very good protection against foreign bodies that may cause infection. This could lead to more effective treatments for conditions affecting the brain and central nervous system, but any unforeseen effects arising from this could be potentially serious, so much more research is needed in this area;
Likewise, any treatment based on nanotechnology must take into account the potential for effects during pregnancy; if nanoparticles could potentially cross the placental barrier between the mother and unborn child, and as a result affect fetal growth or influence fetal development in other ways, then great care is needed to avoid causing unnecessary harm.
This is a fact sheet issued by the Science Media Centre to provide background information on science topics relevant to breaking news stories. This is not intended as the ‘last word’ on a subject, but rather a summary of the basics and a pointer towards sources of more detailed information. These can be read as supplements to our roundups and/or briefings.