Researchers develop dielectrophoretic forceps for toxic nanoparticles

Model diagram of nanogap electrodes enabling dielectrophoretic forceps technology. Credit: Korea Institute of Science and Technology (KIST)

A Korean research team has developed technology that effectively controls fine particles and nanoplastics, which are major causes of human toxicity and ecosystem disturbance. This technology, which allows to sort, purify and concentrate in real time nanoparticles invisible to the human eye, has a great potential of application, not only for the removal of toxic particles from the natural environment, but also for the elimination of viruses and the detection of diseases related to dementia. proteins and cancer diagnostic markers. Due to its wide range of applications, this technology is attracting a lot of attention in scientific and academic circles.

The research team, led by Dr Yong-sang Ryu of the Sensor System Research Center of the National Agenda Research Division of the Korea Institute of Science and Technology (KIST), together with a team led by Dr Sin-Doo Lee from the Department of Electrical and Computer Engineering at Seoul National University, announced the development of a nanogap electrode capable of capturing ultra-fine floating particles as small as 20 nanometers (nm, 1/1000 the thickness of a human hair). The research team used the newly developed electrode in successful experiments of selective concentration and positioning of extracellular vesicles (exosomes), which have potential in the field of drug development and as novel diagnostic markers for them. proteins linked to cancer and dementia.

Researchers around the world are studying techniques to manipulate nanoscale particles without damaging them. The technology of optical tweezers, which received the Nobel Prize for Physics in 2018, is representative of these technologies. However, it has proven difficult to go beyond individual manipulation / measurement at the particle level and achieve large-scale commercialization. Researchers have repeatedly encountered technical limitations in scaling mechanisms to collect, sort, purify, and concentrate particles 100nm or smaller in size; however, such mechanisms are necessary to function in large scale atmospheric and aquatic environments.

The joint KIST-SNU research team, through the production of centimeter-scale devices for particle concentration and purification experiments, was able to overcome these limitations and succeeded in augmenting nanogap electrodes by sandwiching a Nanometric insulating film between two electrodes in a vertical alignment, allowing dielectrophoresis tweezer technology to be applied over large areas. Dielectrophoresis is a technology in which wavelengths vibrating several hundred to several thousand times per second are applied to two electrodes to form a non-uniform electric field distribution around the electrodes. The electrodes are then used to attract or repel the particles in the vicinity of the nanogaps.

The joint research team conducted experiments to find technologies that could use universally available semiconductor processes rather than existing expensive equipment. During the experimentation process, the team found that the dielectrophoretic force produced by the electrodes in a vertical asymmetric electrode array was more than 10 times that of a conventional horizontally aligned nanogap array. This discovery simultaneously solved scaling issues and reduced costs associated with nanogap technology. Using the conventional horizontal electrode array production method, it is quite expensive to produce enough nanogap electrodes to cover the surface of a nail. New dielectrophoresis technology produces enough nanogap electrodes to cover the surface of an LP disc at a fraction of the cost.

The vertical nanogap technology developed by the KIST research team enables to extend nanogap electrode technology, produce nanogap electrodes in many shapes and sizes, and drastically reduce unit production costs. As such, the technology has a wide range of potential applications. According to the research team, when used in air or water filters, nanogap electrodes can operate at low voltage (like that of a regular AA battery) to detect and remove various particles in real time. microscopic floats such as fine dust, nanoplastics, viruses, germs and bacteria.

Lead author of the study, Dr Eui-Sang Yu, said, “This achievement has future application for the sorting and purification of nanoscale particles, regardless of particle type or environment. “

Dr Yong-Sang Ryu of KIST, the corresponding author of the study, added, “We hope that the study can make a broad contribution to solving various social problems and improving the overall quality of human life.

The team develops large-scale expandable and transparent electrodes

More information:
Eui-Sang Yu et al, Precise capture and dynamic relocation of nanoparticulate biomolecules by dielectrophoretic enhancement by vertical nanogap architectures, Nature Communication (2020). DOI: 10.1038 / s41467-020-16630-w

Provided by the National Science and Technology Research Council

Quote: Researchers Develop Dielectrophoretic Tweezers for Toxic Nanoparticles (July 15, 2020) Retrieved September 20, 2021 from

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