Dr. Richard Vachet
Ohio University’s Chemistry and Bochemistry Colloquium Series presents Dr. Richard W. Vachet on “Multiplexed tracking and imaging of nanoparticles in biological samples using mass spectrometry” on Monday, Nov. 20, at 4:10 p.m. in Clippinger Laboratories 194.
Vachet is Professor of Chemistry at the University of Massachusetts-Amherst.
Abstract: Nanoparticles (NPs) are used in over 1500 consumer products and are widely investigated and used in drug delivery, imaging and cancer therapy. Effective use of NPs requires the ability to monitor their distributions for biomedical applications and for their potential adverse environmental, health, and safety effects. We are exploring a new method based on laser desorption/ionization (LDI) mass spectrometry (MS) to selectively track NPs in biological samples. Using LDI-MS, a wide range of NP types can be detected. Furthermore, different NPs can be selectively detected in cells that have taken up these nanomaterials, providing a rapid and sensitive way to study how NP properties influence the cellular uptake of these materials.
The LDI-MS approach can also be used in parallel with inductively-coupled plasma (ICP) MS to monitor the stability of core-shell NPs in cells. This determination is possible because ICP-MS reports on the amount of core material present in a cell, while LDI-MS measures only the ‘shell’ molecules that are attached to the core material. By comparing the amounts of surface molecules and core material measured by the two techniques, the percentage of surface molecules that are retained on the NP can be quantified. In this presentation, I will describe this method and how it has been applied to study how size, surface chemistry, and cell type influence NP stability.
Finally, I will describe how the LDI-MS approach can be used to determine the spatial distributions of NPs in the tissues of mice injected with NPs. By acquiring LDI mass spectra at different locations in thin tissue slices, images of the NP biodistributions can be obtained. This LDI-MS imaging approach can also be combined with laser ablation (LA) ICP-MS imaging to provide site-specific information about NP stability in vivo.
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