Advanced Nanoparticles for Imaging

Application: Imaging

Modern imaging technologies allow for analysis of multi-dimensional and multi-parameter data, especially on analyte presence, tissue properties and to collect additional information on a particular biological function.

The most advanced imaging techniques include CT (Computed Tomography), MRI (Magnetic Resonance Imaging), FLI (fluorescence imaging) and PET (Positron Emission Tomography).

In PET, radioactive probes (radionuclides) are used in conjunction with metabolically active substances or targeting molecules. Positrons are emitted by the breakdown of the radionuclide. Gamma rays are generated when positrons collide with electrons near the decay event. The scanner then detects the gamma rays, which arrive at the detectors in coincidence at 180° apart from one another. These signals are analyzed by a computer to create an image map of the organ or tissue object of the study.

Fluorescence imaging is a particular imaging technology that applies light to investigate molecular and cellular functions in living beings. Images are obtained thanks to the detection of photons of light emitted in the whole light spectrum with specific instruments. It offers a spatial resolution of tens of nanometers and a nanomolar sensitivity of detection.

State of the art

PET offers functional and quantitative information from the whole body but lacks spatial resolution, instead FLI, which provides high-resolution images, but it is limited by poor light penetration in tissues in whole body scanning.

The combination of FLI and PET offers new possibilities, especially in preclinical studies. In particular, it enables scientists to screen the biological samples using cheaper and safer FLI in vitro, to have whole in vivo body images together with functional and quantitative information exploiting PET, and to gather the information about the subcellular distribution of targeted biomarkers thanks to the possibility to perform ex vivo fluorescence microscopy observations of explanted tissues.

AcZon’s solution

AcZon developed NanoRad to meet this combination need. In this multimodal reagent the intrinsically fluorescent silica nanoparticles are conjugated with chelating agents to allow the binding of radionuclides in parallel with targeting/effective molecules.

• Kherlopian AR, Song T, Duan Q, Neimark MA, Po MJ, Gohagan JK, Laine AF. A review of imaging techniques for systems biology. BMC Syst Biol. 2008 Aug 12;2:74.
• Ariztia J, Solmont K, Moïse NP, Specklin S, Heck MP, Lamandé-Langle S, Kuhnast B. PET/Fluorescence Imaging: An Overview of the Chemical Strategies to Build Dual Imaging Tools. Bioconjug Chem. 2022 Jan 19;33(1):24-52.