Since the Industrial Revolution, nanoparticles are considered one of the most essential engineering innovation by several scientists and scholars. It has the capability to re-engineer the man-made world molecule by molecule sparking a wave of opportunities in the multitude of fields from health to stealth.
Surprisingly, this technology has an astonishing long history of more than 1700 years in a timeline. Though, it was R. Feynman who introduced the concept of nanoparticles in 1959 for the very first time. He proposed in his famous lecture entitled ‘There’s Plenty of Room at Bottom’ at the meeting of American Physical Society. However, Japanese professor Norio Taniguchi later coined the term ‘Nanotechnology’ to describe ultra-fine dimensions.
Nanotechnology; a study which revolves around particles which are engineered at nanoscale level promises great possibilities in a myriad of disciplines including automobiles, medicine and so on. If explained in simple words, any particles which are crore times or 10 million times smaller than a centimeter can be referred as nanoparticles (NPs). Surprisingly, some types of NPs are also found naturally in organic (protein, viruses and others) or inorganic forms. Inorganic compounds such as carbons, iron oxyhydroxides, metals among others exist as the result of weathering, volcano eruptions, wildfires or due to other reasons.
What are NPs and its Types?
Any particles having 100 to 10,000 atoms and whose size roughly ranges between 1 to 100nm can be defined as NPs.
NPs engineered from silver, gold or carbon are the most common types which are currently employed by researchers. Each type of nanoparticles has unique physical and chemical properties.
Silver Nanoparticles (AgNPs)
It is one of the most commonly used NPs and is synthesized from silver. AgNPs are frequently used in food, medical, health-care and industrial sectors because of its unique optical, biological and antimicrobial properties. Moreover, these particles also exhibit high thermal and electrical conductivity. With its unique characteristics, AgNPs are majorly used as an antimicrobial agent, medical device coatings and for drug delivery. Additionally, it is also used as an anticancer agent with enhanced tumor killing effects, optical sensors and is also useful in cosmetics. Recently, its usage was also observed in keyboards, wound dressings and textiles.
Gold Nanoparticles (AuNPs)
With the history of several thousand years and one of the first metals discovered by mankind; gold is another common type of material used for synthesizing NPs. Although, gold colloids were first made by Faraday in 1857 but, the first data on colloidal gold can be tracked in treatises by Indian, Arabian, and Chinese scientists in fifth and sixth centuries BC mostly for medicinal purposes.
With its versatility, AuNPs has applications in genomics, immunoanalysis, detection and photothermolysis of microorganisms. It can be used to destroy cancer cells too. Now, AuNPs is also an option of choice for drug delivery and bioimaging. It has been argued that gold NPs can be used in all medical applications.
Carbon nanoparticles (CNPs)
Carbon is the 4th most abundant element in universe following hydrogen, helium and oxygen. It forms more compounds than any other elements. Abundance, together with unique properties, makes this element the chemical basis of all known life forms on the Earth.
There are several techniques like carbonization, activation and grinding for the synthesis of CNPs. However, its non-reactive nature makes it safe to synthesize even in the home by just using a microwave oven. CNPs are the most stable and small in size when compared to others. Among many, the most significant property of these particles is its ability to fluoresce making it essential tool in the field of bio-imaging. Furthermore, its cell membrane penetration capability because of its very small size and low toxic nature makes it useful for drug targeting or personalized medicines.
In essence, to summarize all, this fascination of NP research has led to unusual, often unpredicted results. Although some of its principles are being used for several hundreds of year; systemic studies of NPs began just a few decades ago with research lingering far from deeply explored. New NPs of different properties are still being created, new effects still being discovered, new concepts still being developed to understand and explain the very basics of the ‘SMALL’.
This was the very brief and simple introduction to Nanoparticles. In forthcoming articles, we’ll try to cover all its applications in details. Meanwhile, we’ll be encouraged if you will share this article with the right crowd and please do post your opinions, doubts and feedbacks in the comment section below.
Till then, Keep reading, Keep Learning & Keep Thinking.
For Further Reading