1 results for Ali, Nadiah

  • Detection of Inorganic and Metal Nanoparticles using qNano – IZON Science’s Nanoparticle Analysis System

    Ali, Nadiah (2011)

    Masters thesis
    Victoria University of Wellington

    This thesis investigates the potential and capability of the qNano instrument, a nanoparticle analysis research instrument developed by IZON Science Ltd. The qNano operates on the basis of the Scanning Ion Occlusion Spectroscopy (SIOS) technology which is similar to the Coulter technique also known as resistive pulse sensing. This coupled with an adjustable nanopore and IZON’s recently developed Variable Pressure Module (VPM) makes qNano a versatile nanoparticle analysis apparatus. In this study the potential of the instrument to detect inorganic and metal nanoparticles is explored. Polystyrene, silica, gold, silver, and magnetic nanoparticles have been used in this research to better understand the system and its components and to discover the capacity of the instrument to detect these particles. Using polystyrene nanoparticles, it was found that the adjustable nanopore exhibit membrane softening and follows the Mullins effect. Each of the apertures also possesses a characteristic window of operation, which refers to a range of stretch setting for accurate particle detection. The adjustable nanopore also allows for sizing particles with different diameters. The effect of surface functionality in the signal output was also investigated. Gold nanoparticles were synthesized via the citrate reduction method and the study of gold nanoparticles suspended in IZON’s standard buffer solution was looked into in depth. It was found that the gold nanoparticles aggregate in the buffer solution due to the presence of potassium chloride (KCl) salt which screens the electrostatic stabilization provided by the citrate ions. Silver nanoparticles show similar aggregation. With the concentration of gold and KCl remaining constant, resistive pulses caused by gold aggregates were detected after a period of three hours. Varying the concentration of gold nanoparticles shows that larger aggregates are formed as opposed to small aggregates with higher population. Identification of different types of particles present in a solution is yet to be achieved at this stage. Silica and magnetic nanoparticles were studied briefly. Successful measurements of magnetic particles were achieved with the aid of the pressure module. However, aggregates of magnetic particles were also formed and can be seen with the naked eye after solution was left standing overnight. Casein stabilized silica particles shows erratic current readings as the ethanol used in fabricating the silica particles collapse the casein micelle structure thus making the stabilization by casein void. Overall, this thesis has shown the qNano instrument’s ability in detecting nanoparticles other than biological molecules. This thesis also shows the potential of qNano as a versatile research instrument. The prospect of further research using this instrument is tremendous especially in characterising in greater detail inorganic and metal nanoparticles.

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