posted on 2021-03-11, 15:08authored byGiovanni M. Saladino, Carmen Vogt, Yuyang Li, Kian Shaker, Bertha Brodin, Martin Svenda, Hans M. Hertz, Muhammet S. Toprak
Nanoparticle (NP)
based contrast agents detectable via different
imaging modalities (multimodal properties) provide a promising strategy
for noninvasive diagnostics. Core–shell NPs combining optical
and X-ray fluorescence properties as bioimaging contrast agents are
presented. NPs developed earlier for X-ray fluorescence computed tomography
(XFCT), based on ceramic molybdenum oxide (MoO2) and metallic
rhodium (Rh) and ruthenium (Ru), are coated with a silica (SiO2) shell, using ethanolamine as the catalyst. The SiO2 coating method introduced here is demonstrated to be applicable
to both metallic and ceramic NPs. Furthermore, a fluorophore (Cy5.5
dye) was conjugated to the SiO2 layer, without altering
the morphological and size characteristics of the hybrid NPs, rendering
them with optical fluorescence properties. The improved biocompatibility
of the SiO2 coated NPs without and with Cy5.5 is demonstrated in vitro by Real-Time Cell Analysis (RTCA) on a macrophage
cell line (RAW 264.7). The multimodal characteristics of the core–shell
NPs are confirmed with confocal microscopy, allowing the intracellular
localization of these NPs in vitro to be tracked
and studied. In situ XFCT successfully showed the
possibility of in vivo multiplexed bioimaging for
multitargeting studies with minimum radiation dose. Combined optical
and X-ray fluorescence properties empower these NPs as effective macroscopic
and microscopic imaging tools.