Nanoparticles: Big advancements in the science of the miniature

Anna Brinks ’21

A computerized model of a semiconductor nanoparticle, or quantum dot. This NP consists of lead sulfide and is completely passivated (treated to reduce the chemical reactivity of its surface) by oleic acid, oleyl amine, and hydroxyl ligands (size ~5nm.) (Source: Wikimedia Commons)

Nanotechnology is a rapidly growing science with applications across numerous fields, including chemistry, biology, physics, and engineering. The famous lecture “There’s Plenty of Room at the Bottom” delivered by Nobel laureate Richard Feynman in 1959 marked the emergence of nanotechnology in the scientific community, and since this debut numerous advances have been made both in the creation of novel materials as well as their integration into devices.1 In the review “Nanoparticles: Properties, Applications and Toxicities,” Ibrahim Khan and colleagues provide an expansive view of nanotechnology’s progress and its wide array of potential applications.

Nanotechnology is focused primarily on the development and investigation of nanoparticles (NPs). A diverse field of materials, nanoparticles may be divided into several categories that each display unique physical and chemical characteristics. To be classified as a nanoparticle, a material must have at least one dimension less than 100nm.1 Current well-known classes of nanoparticles include carbon-based NPs such as fullerenes (made of globular, hollow cages of atoms), metal NPs (especially gold), ceramic NPs, semiconductor NPs, polymeric NPs, and lipid NPs. These classes of nanomaterials may be synthesized via top-down synthesis, whereby a larger molecule is decomposed into smaller units that are then converted into NPs. Alternatively, bottom-up syntheses involve starting with simpler substances and building up from atoms to molecules to the final structure.1

The characterization of NPs is a critical component of their development. Morphology, structure, particle size, surface area, and optical characterizations must all be acknowledged to identify possible opportunities for the NP’s practical use.1 These characteristics must be determined at a nanoscale level and may involve techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and countless others. Additionally, physiochemical properties such as electronic, mechanical, magnetic, and thermal properties may also be important.

With the wide range of unique properties and capabilities that NPs display, there is huge potential for their integration into many fields. In medicine, NPs can be used to deliver drugs more effectively and with fewer side effects. They may also provide contrast for biological and cell imaging. Silver NPs have been increasingly used in wound dressings, catheters and various household products due to their antimicrobial activity.1 In manufacturing, NPs can be exploited for anything from food packaging and processing to chemical sensors. Numerous applications in electronics, energy harvesting, and sustainability are also under development.1

As nanotechnology continues to become more sophisticated and NPs become increasingly prevalent in daily use, it will be important to thoroughly investigate their potential toxicities (both in the human body and the environment) in order to develop proper safety guidelines. Further exploration of the effects of human exposure to NPs at various concentrations is necessary, as is research into how their interaction with organic materials in the environment may affect ecotoxicity (substances that damage ecosystems).1 With continued research and judicious safety practices, NPs have the potential to revolutionize technology and greatly improve quality of life.

References:

[1] Khan, I., Saeed, K., & Khan, I. (2019). Nanoparticles: Properties, applications and toxicities. Arabian Journal of Chemistry, 12(7), 908–931. https://doi.org/10.1016/j.arabjc.2017.05.011

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