Characterization of bioorganic and inorganic nanoparticles

Nanoparticles are ubiquitous in natural and technological environment. When airborne, they are called nanoaerosols, or bio-nanoaerosols, depending on the kind - inorganic vs. bioorganic - of particles. Since nanometer-sized particles are comparable with macromolecules based e.g. on their mass, it is sensible to utilize, improve and further develop nanoaerosol measuring techniques for analysis of very small particles, of very large molecules. The proposed project is focused in the first stage on a construction of an improved Parallel Differential Mobility Analyzer (PDMA), a nanoaerosol measuring system based on patent granted to applicants. The proposed system is particularly suitable for characterization, separation and enrichment of inorganic and bioorganic nanoparticles. Moreover, the system allows investigating structure and conformational changes of macromolecular complexes in nearly physiological situations. Biopolymers` primary structure is certainly of great importance, the biological activity however is controlled by relatively weak, non-covalent bonds. Parameters such as acidity, temperature or irradiation can result in a denaturation, or the loss of biological activity. Advances to observe these processes under atmospheric pressure are limited so far. The proposed nanoaerosol technique along with mass spectrometry and TEM, AFM analysis opens wide areas of identification, characterisation and quantification of various nanoparticles including biopolymers and their reaction monitoring in view of the fact that the nanoaerosol measuring approach preserves the solution based stoichiometry. Finely, we would focus on the issue of electrostatic mobility classification of elongated nanoparticles. The production of single-walled small nanotubes and its application in electronic and semiconductor industry requires well-defined tube classes in terms of dimension and chemical properties. The size determination and the distribution of sizes are there of an utmost importance and PDMA could play an important role in delivering this information. The behaviour of rod-like nano-objects (single walled carbon nanotubes, chemical-linked dendrimers or gold nanorods.) in mobility analyzers is rather poorly understood and will be investigated in scope of the development of this tool as analytical and semi preparative device. The mobility spectra analysis will be then linked to the nanoparticles collected by the electrostatic nanosampler and analyzed afterwards by electron and atomic force microscopy. Based on such experiments we will attempt to provide a firm answer if the proposed technique is suitable for this kind of industrial application.

Aerosol nanoparticles are abundant in natural and man-made environment. Air quality studies and health impact of particles, in particular of nanoparticles, are being conducted with an increasing level of interest in the academic and also non-academic community. The potential risks to the health and environment of engineered nanoparticles and consequently nanomaterials become increasingly the focus of general attention in recent years. Furthermore, characterization of engineered bio-nanoparticles is gaining importance in biotechnology, medicine, food technology and pharmaceutical industry. A methodology and an instrument for measurement of airborne nanoparticles in real time has been developed, constructed and employed for characterization of various biological and non-biological nanoparticles the Parallel Differential Mobility Analyzer (PDMA). The operation of the PDMA occurs under ambient temperature and pressure resulting in non- destructive measurement. The basic principle here is how a nanoparticle moves in a defined electrical field. The prerequisite for such a measurement is that every nanoparticle must be airborne and carry a well-defined electrical charge. In order to make nanoparticles airborne a soft nano-electrospray process has been refined used preserving noncovalent bio-specific interactions, i.e. keep biological species as viruses functional. Following that a charge conditioning procedure was applied by interspersing of bipolar air ions with nanoparticles in question. Various origins of ions such as radioactive sources, soft x-rays, of electrical discharge were used and their charging suitability investigated. Following the well-defined charging process particles were exposed to an electrical field inside the PDMA in which they move on trajectories which can be correlated with particle size down to the low nanometer diameter range. For a given particle size and an electrical field strength the measured nanoparticle can leave the PDMA and can be detected. Varying the electrical field strength nanoparticle sizes in the range from 1 nm up to about 500 nm were measured. The outstanding accuracy of the method allows measurement of particle size and the increase of particle size within few percent. This in consequence provides a unique tool for characterization, manipulation and sampling of nanoparticles. For the first time the size as well as molecular mass of the intact (i.e. completely functional) human rhino-virus was measured in the airborne state. Moreover, we were able to analyze the native virus including the genetic information as well as its derived sub-viral particles after a heat treatment of the virus. Because it is possible to measure a minute increase (nanoscale) in particle size we also demonstrated that it is feasible to determine the number of specific antibodies attached to a virus-like nanoparticles.. Given that geometrical (spherical shape) constrains were considered we were able to derive molecular masses of various bio-nanoparticles even such as an intact human rhinovirus with high accuracy and not accessible by classical mass spectrometry methods.