Kibong Choi

DEVELOPMENT OF A BIOLOGICAL AEROSOL DETECTOR USING LASER-INDUCED FLUORESCENCE AND A PARTICLE COLLECTION SYSTEM

A real-time biological aerosol fluorescence detector was designed for monitoring aerosols in the atmosphere. The operating principles of the current biological aerosol monitoring system (BAMS) include the measurement of optically determined single particle properties, two fluorescence bands, and a scattering signal. Furthermore, the development of an algorithm to significantly increase the biological aerosol discrimination is described, which uses the results of the experimental evaluation of a number of aerosols in an evaluation chamber in the laboratory. The detector was applied to seasonal pollen, Asian dust, seawater environment, industrial zones, and residential areas in Korea. Applications of the device include all aspects of biological aerosol monitoring, including use as a biological agent trigger and as a hazardous environment monitor. The detectors were used in various laboratories as an ambient biological aerosol monitor and in various fields as a fast biological threat agent trigger in the 2010 G20 Seoul Summit and 2012 Nuclear Security Summit.

Sensitivity enhancement of surface plasmon resonance biosensor with colloidal gold

We enhanced the sensitivity of surface plasmon resonance biosensor by the conversion of the real-time direct binding immunoassay into the sandwich immunoassay, in which colloidal gold particles coated with anti-mouse IgG was used. By the immobilization of anti-mouse IgG onto the carboxymethyl dextran surface of thin gold film, the direct binding of analyte (mouse IgG) onto the sensor chip, and the injection of colloidal gold particles coated with antimouse IgG, about 100 times of sensitivity enhancement was obtained. This result suggests that nanoparticles, which has a high refractive index, homogeneous ultrafine structure and capability of size control, would be applicable for the detection of very small quantity of biomaterial.

The Effect of Inkjet Operating Parameters on the Size Control of Aerosol Particles

We investigated the effect of inkjet operating parameters on the size control of aerosol particles. Droplets with agglomerates of polystyrene latex particles were generated from an inkjet nozzle and continuously dried up at the temperature of 38°C. When droplets have the size range of 30 to 70 μm in diameter, aerosol particles with the size range of 3.5 to 7.1 μm were generated after the drying process. We controlled the particle size easily within a factor of two by adjusting rising/falling time and voltages of an actuating waveform. Generated particles were shown to have a narrow particle size distribution. Thus, the particle concentration of aqueous suspension does not need to be adjusted precisely in order to control the size of generated aerosol particles. Copyright