Development of Wet Electrostatic Precipitator for Generation of Nanoparticle-Protein Solution

Abstract: To examine nanoparticle toxicity there is a need to produce defined nanoparticles dispersed in a colloidal suspension. Such a solution could also be interesting for other fields such as nano-medicine. In order to disperse the particles in the liquid there are often surfactant added to the process that alternates the surface of the particles. As the research shows that the surface of a nanoparticle can play a large role of its effects in biological systems, the relevance of these methods have been questioned. By depositing the airborne particles directly in a liquid this mentioned primary treatment can be avoided. A new method for depositing on liquid has been developed that appears to avoid the formation of a film consisting of stagnant nanoparticle-protein complexes. Particles deposited on a recirculating liquid by the means of electrostatic forces, the method is realized in a device-named Aeroid. The methodology also allow larger volumes of fluid with suitable concentration. Also the size of nanoparticles can be produced which, from an application perspective, is desirable. Design, loss measurements and efficiency measurements were included in the method development for the Aeroid. Analyses in the form of materials, volume of the liquid and on how the particles are expected to move in the electric field was performed. For deposition in the Aeroid an aerosol of spherical goldnanoparticles was employed, with size about 60 nm, produced by means of a spark generator in series with a high-temperature-oven. The aerosol is then passed through a bipolar charger to obtain a well known charge distribution, Boltzmann-Fuch. To determine which type of protein solution that could be used to produce a colloid solution with 60 nm gold particles in the Aeroid a control measurements in an ESP where made. There was two types of proteins IgG and BSA added into water, PBS and TRISS. The deposit was made with the same length of time and with the same aerosol concentration for all control measurements. The reddest membrane i. e. the highest concentration of gold nanoparticle-protein complex was found when the BSA was dissolved in PBS. This solution was used for depostion in the Aeroid. When the voltage with a field strength of 1.2 kV/cm, was turned on in the Aeroid 17 % of the produced particles where deposited. It resutled in losses between 13 and 37% at 60 nm, most likely due to diffusion. Efficiency measurements were carried out partly in a SMPS by comparing the penetration of particles in the Aeroid when high voltage was on/off. A complement to the deposition measurement PIXE analysis to determine the concentration of gold in the liquid. Analysis by spectrophotometry and visual inspection shows that generation of a 65 ml solution of dispersed gold nanoparticles was successfull. Future research and development should put emphasis on the analysis of the proportion of the particles which are dispersed in order to evaluate whether the Aeroid may be used for the production of other types of particle-protein solution combinations.