Metal nanoparticles – pros and cons

Nanoparticles (NPs) have become ubiquitous, with an estimated 1600 commercial products available. However, the NPs are inevitably later released into the environment.

Silver is the engineered metal NP most commonly found, with approximately 65 tonnes released into rivers globally per annum. Silver has biocidal activity on account of its disruption of the enzyme function responsible for nutrient uptake, and cellular energy production and storage processes.

These powerful antibacterial properties have led to silver NPs being used in many commercial products, such as medical dressings, food preparation items and clothing (where around 50% of the NPs leach out per washing cycle). Significantly, silver NPs cause endocrine disruption in amphibians and are toxic to many mammalian organs.

Rapid, sensitive diagnostic method

To characterise the risk posed to ecosystems by increased exposure to silver NPs, the development of detection techniques is urgently required.

Oxford researchers have developed a fast and sensitive method of detecting and identifying silver NPs in a sample, which on entering the natural environment, may pose a public health risk.

Their method involves assessing the presence and/or properties of the particles in a sample from electrochemical responses yielded by the particles colliding with an electrode, and allows identifying, quantifying, and characterising of particles in a sample.

Competitive advantage

This is the first time that the direct electro-oxidation of silver NPs colliding with an electrode is both viable and quantitative, and can be used for characterisation and NP identification. The method uses low cost carbon electrodes.

Additionally, electrochemical methods lend themselves to use with low cost and compact electronics, making this a method that could be widely deployed. Also, the ability of the method to identify, quantify and characterise NPs provides it with excellent potential in environmental compliance monitoring and public health.

Research is already under way to extend the method to the quantitative characterisation of other metal NPs, as well as mixed NP systems.

Patent protection

The underlying technology is the subject of a UK patent application. Request more information if you would like to discuss this further.