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The scientific field of metrology refers to the ability to obtain measurements of almost any type of object. Branching from this umbrella term is the field of nanometrology, which involves the precise measurement of sizes that are within the size range of 10 to 100 nanometers (nm). Nanometrology can also be used to describe the ability of scientists to research new methods or develop adaptations to existing methods capable of characterizing material properties in terms of their size. Any advancements that are made within the field of nanotechnology cannot occur without prior nanometrology advancements to confirm these technological developments.
Nanometrology Techniques for Biological Science
There are numerous different analytical instruments that can be used within the field of nanometrology, depending on the application in which the nanoscaling will be performed. Overall, nanometrology techniques can be divided into five major principle categories including spectroscopy, microscopy, light scattering, separation and single particle inductively coupled plasma-mass spectrometry.
Some examples of the specific analytical instruments used for nanometrology purposes within the biological and medical sciences include:
- Transmission Electron Microscopy (TEM)
- Optical Tweezers Techniques
- Scanning Probe Microscopy (SPMs), such as:
- Electrochemical Scanning Tunneling Microscopy (EC STM)
- Magnetic Force Microscopy (MFM)
- Friction Force Microscopy (FFM)
- Scanning Near-Field Optical Microscopy (SNOM)
- Atomic Force Microscopy (AFMs)
Traditional Applications of Nanometrology in Biological Science
Within both the biological and medical fields, the aforementioned analytical techniques are widely used to characterize the properties of viruses, bacteria, living cells, small metal particles and strands of DNA. Additional applications of nanometrology within these biological fields include the manipulation, confinement and organization of cells for sorting purposes, as well as the continuous monitoring of cell movement. Each of these tasks often require the ability of scientists to maintain a greater than normal amount of control over their sample sizes, force masses and other physical properties to ensure that they are operating within the nanoscale.
Nanometrology in Environmental Research
The development and widespread use of engineered nanoparticles (ENPs) can be found in almost every possible industry around the world. As the use of ENPs continues to rise, their presence in commonly used goods, such as cosmetic and food products, has caused toxicologists to become increasingly concerned as to how these particles can affect human, animal and environmental health. For example, silver nanoparticles (AgNPs) are one of the most popular types of ENPs used in a variety of different industries as a result of their antibacterial characteristics. While this may be true, the hazards associated with unwanted exposure to AgNPs has also risen.
As a result of the concern that has risen in response to the growing use and release of nanoparticles into the environment, environmental scientists have turned to various nanometrology analytical techniques to conduct toxicity and exposure assessments of these ENPs. Microscopy is typically used to obtain images of ENPs, as well as gather information on their elemental composition. More specifically, electron microscopy techniques like TEM and SEM, which can reach a resolution of about 0.07 nm and 1 nm, respectively, are particularly advantageous for these purposes. It is important to note that a minimum of 200 discrete particles is typically required to obtain representative information on the shape, size and size distribution characteristics of a given set of ENPs.
In order to obtain information on ENP concentrations, analytical instruments can vary from parts per trillion (ppt) to parts per million (ppm) in terms of their sensitivity capabilities. Ultraviolet-visible spectroscopy (Uv-Vis), dynamic light scattering (DLS) and inductively coupled plasma mass spectrometry (ICP-MS), for example, are capable of detecting ppt levels.
As nanotechnology continues to develop across industries, its inevitable dependence on nanometrology techniques will follow. Within the biological sciences, nanometrology can be applied to various areas ranging from validity purposes in research to environmental risk assessments.
Sources and Further References
- “Nanometrology” – European Nanotechnology Gateway
- Jamakhani, M. A., Jadhav, M . R., Kamble, G. S., & Gambhire, V. R. (2011) International Journal of Advanced Biotechnology and Research 2(1); 213-223.
- Kim, H., Seo, J., et al. (2014). Nanometrology and its perspectives in environmental research. Environmental Health and Toxicology 29. DOI: 10.5620/eht.e2014016.