What are metal nanoparticles?

Metal nanoparticles are submicron scale entities made of pure metals (e.g., gold, platinum, silver, titanium, zinc, cerium, iron, and thallium) or their compounds (e.g., oxides, hydroxides, sulfides, phosphates, fluorides, and chlorides) [44,45]. From: Nanobiomaterials in Clinical Dentistry, 2013.

What are nanoparticles in chemistry?

A nanoparticle is a small particle that ranges between 1 to 100 nanometres in size. Undetectable by the human eye, nanoparticles can exhibit significantly different physical and chemical properties to their larger material counterparts.

What are the properties of metal nanoparticles?

The optical properties of metal nanoparticles are governed by collective excitation of the conduction electrons. The electrons oscillate coherently under irradiation by light in the visible and near-IR regions of the electromagnetic spectrum. These coherent oscillations are known as local surface plasmon resonances.

How are metal nanoparticles synthesized?

The sol gel method of nanoparticles synthesis involves either; a) Mixing of preformed colloids metal (oxide) with a sol containing the matrix-forming species followed by gel formation, b) Direct mixing of metal and metal oxide or nanoparticles within a prehydrolysed silica sol.

Why are metal nanoparticles Coloured?

Nanoparticles appear certain colors because they reflect (scatter) and absorb specific wavelengths of visible light.

What are nanoparticles made from?

Free nanoparticles are formed through either the breaking down of larger particles or by controlled assembly processes. Natural phenomena and many human industrial and domestic activities, such as cooking, manufacturing or road and air transport release nanoparticles into the atmosphere.

What are the physical and chemical properties of nanoparticles?

The principal parameters of nanoparticles are their shape, size, surface characteristics and inner structure. Nanoparticles can be encountered as aerosols (solids or liquids in air), suspensions (solids in liquids) or as emulsions (liquids in liquids).

What are metal nanoclusters?

Nanoclusters are gold compounds with a core of metal atoms and organic groups covalently bound to the surface gold atoms. Due to their small size, these nanoclusters exhibit intrinsic near-infrared (NIR) fluorescence.

Which type of enzyme is used in biosynthesis of metal nanoparticles?

Microorganisms are cost effective and do not have high energy requirements. In addition, they can accumulate and detoxify heavy metals through reductase enzymes, which reduce metal salts to their corresponding metal nanoparticle with less polydispersity and a narrow size range [16].