Grant: Research Tools and Instruments - Category 1 (<$150,000)

This proposal is for the purpose of purchasing a total reflection X-ray fluorescence (TXRF) spectrometer, and associated equipment, for the purpose of the in situ low-level quantification of gold, in the form of gold nanoparticle, in cell cultures and tissues, a fundamental, and currently limiting requirement for the advancement of the study of nanoparticle aided therapies. The application of ultrasound-microbubbles in combination with gold nanoparticles is being investigated to improve therapeutic outcome of radiotherapy and laser-mediated thermal therapy of cancerous tissues. Although the general physical mechanism of the action of gold nanoparticles in aiding such therapies is largely known, the optimal method of therapeutic delivery, and an understanding of gold nanoparticle uptake into cells, is still missing. This requires that an accurate in situ measure of gold delivered to cancerous cells be known. Gold quantification is a challenge in such a case as most wet chemical methods require total destruction of the sample, and do not generally present limits of detection which are sufficient to detect and quantify the very low levels of gold expected in cells after treatment with gold nanoparticles. TXRF offers very low limits of detection (at ppb levels), and being based on X-ray fluorescence allows for complete in situ quantification of gold in thin layer samples, including, mono- and multi-layer cell cultures. A similar, but complementary, area of potential application of TXRF would be in the assessment of other trace elements in human tissues, such as in teeth or bone, or in environmental, archeological and art samples in the future.