Search

An original synthesis method based on X-ray irradiation produced gold nanoparticles (AuNPs) with two important properties for biomedical research: intense visible photoluminescence and very high accumulation in cancer cells. The nanoparticles, coated with MUA (11-mercaptoundecanoid acid), are very small (1.4 nm diameter); the above two properties are not present for even slightly larger sizes. The small MUA-AuNPs are non-cytotoxic (except for very high concentrations) and do not interfere with cancer cell proliferation. Multimodality imaging using visible light fluorescence and X-ray microscopy is demonstrated by tracing the nanoparticle-loaded tumor cells. (C) 2012 Elsevier Inc. All rights reserved.

article i nfo Complete profiling would substantially facilitate the fundamental understanding of tumor angiogenesis and of possible anti-angiogenesis cancer treatments. We developed an integrated synchrotron-based methodology withexcellent performances: detection of very small vessels by high spatialresolution (~1 μm)and nanoparticle contrast enhancement, in vivo dynamics investigations with high temporal resolution (~1 ms), and three- dimensional quantitative morphology parametrization by computer tracing. The smallest (3-10 μm) microves- sels were found to constitute >80% of the tumor vasculature and exhibit many structural anomalies. Practical applications are presented, including vessel microanalysis in xenografted tumors, monitoring the effects of anti-angiogenetic agents and in vivo detection of tumor vascular rheological properties.

Our experimental results demonstrate that full-field hard-X-ray microscopy is finally able to investigate the internal structure of cells in tissues. This result was made possible by three main factors: the use of a coherent (synchrotron) source of X-rays, the exploitation of contrast mechanisms based on the real part of the refractive index and the magnification provided by high-resolution Fresnel zone-plate objectives. We specifically obtained high-quality microradiographs of human and mouse cells with 29 nm Rayleigh spatial resolution and verified that tomographic reconstruction could be implemented with a final resolution level suitable for subcellular features. We also demonstrated that a phase retrieval method based on a wave propagation algorithm could yield good subcellular images starting from a series of defocused microradiographs. The concluding discussion compares cellular and subcellular hard-X-ray microradiology with other techniques and evaluates its potential impact on biomedical research. (C) 2012 Elsevier Inc. All rights reserved.