In an interdisciplinary research in which CIC biomaGUNE has participated, drug delivery nanocapsules have been synthesized with three contrast agents for three biomedical imaging techniques to study their biodistribution in vivo. CIC biomaGUNE's Radiochemistry and Nuclear Imaging group, led by Jordi Llop, and the Magnetic Resonance Imaging group, led by Pedro Ramos-Cabrer, have collaborated with a research group from the Institute of Materials Science of Barcelona (ICMAB-CSIC) and the Vall d'Hebron Research Institute (VHIR), and with the University of Artois (France), in this study recently published in the journal Nanoscale.

Nanocapsules are used for drug delivery of insoluble, highly sensitive, or multi-components drugs, and to protect them from degradation, inactivation or clearance, etc. Furthermore, nanocapsules allow the functionalization or modification of its surface, so contrast agents for biomedical imaging can be chemically attached, as is the case in this study.

The biomedical imaging techniques used in this study include magnetic resonance imaging (MRI), fluorescence (blue and near-infrared) and positron emission tomography (PET). All three are non-invasive diagnostic by imaging and experimental research tools that allow to visualize where the nanocapsules are in the organisms in real time.

Using more than one contrast agent to study the in vivo biodistribution of a nanodrug provides additional information, since the three imaging techniques have different sensitivity and resolution limits, and can be used at different levels of drug development, or to detect biodistribution in different tissues of the human body.

The nanocapsules are made of a biodegradable and biocompatible biopolymer, PLGA (poly (lactic-co-glycolic acid)), approved by the FDA (United States Food and Drug Administration). The study confirms that they are safe both in vivo and in vitro.
Furthermore, the particularity of the nanocapsules synthesized in this study is that they have been functionalized in a modular way, since the three imaging probes can be added and removed separately or simultaneously. This fact allows that in each nanodrug development, a different imaging technique can be used to validate the results.

These contrast agents are used in all three biomedical imaging techniques, maintaining the size and shape of the nanocapsules, and without cross interference with the others or with the drug encapsulated inside the nanocapsule.

A great challenge in nanomedicine is how to make a local non-invasive administration of nanomaterials with a controlled release of the therapeutic agent, especially in difficult-access tissues, such as the brain. Thus, having new biocompatible formulations that allow in vivo neuroimaging monitoring is necessary in pre-clinical research phases to assess the development of specific treatments.