In Vivo Study of Polyelectrolyte Microcarriers Loaded with Zinc Phthalocyanine for Image-Guided Photodynamic Therapy

In this work, we investigate a hybrid system based on a biocompatible polymer matrix loaded with a fluorescent photodynamic dye zinc phthalocyanine as a platform with high photodynamic activity in the first biological window and the ability to visualize the biodistribution of the system in vivo. In this regard, biocompatible polyelectrolyte carriers of submicron size were used, which enable efficient immobilization of low-molecular-weight dyes and carry out photodynamic therapy without uncontrolled release of the photodynamic agent. Since the thickness of the polyelectrolyte shell of the carrier do not exceed several tens of nanometers, and the lifetime of singlet oxygen enable motion over distances of up to several microns, the photodynamic activity of the immobilized agent can be observed even without the release of the photodynamic agent from the polyelectrolyte carrier, thus making the carrier itself a photodynamic agent. The ability to flexibly vary the composition of the polyelectrolyte shell of the carriers allows it to include functional organic and inorganic components, which makes it possible to provide the function of visualizing the biodistribution of the delivery system in vivo during circulation in the body. The system described in this work will provide additional functionalization of the carriers, such as the ability to visualization of the biodistribution of submicron polymer carriers loaded with photodynamic agents in laboratory mice in vivo which has been investigated in this work. These results open up a venue for the therapy based on the principles of "image-guided therapy".