Introduction

Process for preparing “core-shell” particles from encapsulation by coacervating contrast agents for multimodal imaging purposes. Coacervation is a phenomenon whereby, under particular conditions, the particles of a hydrophilic substance are grouped in a liquid aggregate. However, while considered very interesting because it is scalable and low-cost, coacervation in diagnostic imaging has so far been limited by the difficulty of combining stable nanostructures and contrast agents. The aim of this process is to make coacerved products biocompatible and able to permanently encapsulate contrast agents, thus avoiding the risk of unwanted release within the body.

Technical features

Coacervation process combining the presence of two cross-linking agents with strict control of the complex coacervating conditions of biocompatible polymers during the separation phase, in order to obtain stable and biocompatible coacervate particles encapsulating multimodal contrast media. The process consists of: a.Providing water in biocompatible polyelectrolyte polymer oil emulsion. b. Provide an aqueous solution of a biocompatible polyelectrolyte polymer having opposite charges of step polyelectrolyte a). c.Addition of a cross-linking agent to the primary emulsion and to the secondary solution. d. Addition of at least one independent tracer to the primary emulsion or to the secondary solution or emulsion. e. Addition of secondary aqueous solution to primary emulsions and appearance of complex coacervation leading to separation of coacervate particles. f. Optionally absorb an additional tracer in the nanoparticles. Preferably, coacervate particles are used, after loading with appropriate contrast agents, as a single probe for trimodal imaging, in particular by combining simultaneous MRI, PET and fluorescence.

Possible Applications

• Multimodal imaging
• Teranostic applications

Advantages

• Scalable and low-cost process
• High load (up to 99%) of nanostructures produced with controlled release properties
• Simultaneous acquisition of PET/RMI images
• Biocompatible and highly specific tissues
• Increased sensitivity