Quantification of gold nanoparticles in histologically thin tissue slices using TXRF

Abstract

<p>The promise of gold nanoparticles (AuNPs) in cancer applications remains an active area of research. The assessment of tumoral uptake can provide valuable insights into their intended efficacy. Total X-ray reflection fluorescence (TXRF) spectroscopy offers low detection limits coupled with direct quantification through internal standardization. These features enable TXRF to measure uptake of AuNPs in the presence of organic matrix. In this work, we demonstrate TXRF's ability to directly quantify AuNP concentration in slices of tissue. Bovine liver was cut into 5 μm thin slices, and 10 nm reference material AuNPs were deposited either above or below the tissue. The tissue slice was then spiked with a lanthanum (La) internal standard. In order to extend the investigation to homogenous samples, a TOPAS-based simulation toolkit was used to model Au-containing tissue. Additionally, scanning electron microscopy (SEM) was used to examine the distribution of the Au and La on the tissue slices, revealing elemental uniformity on the tissue surface. The experimental and simulation results revealed nearly 100% quantification accuracy of AuNPs in all permutations of sample configuration—making TXRF a viable option for assessment of tumoral AuNP uptake with minimal sample preparation.</p>