Fluorescence Visualization of Upconversion Complexes in Transplanted PC1 Liver Cancer and Rat Organs: Influence of Coating Nanoparticle Complexes

Fluorescent imaging of nanoparticles (NPs) in organs and tumors is an important part of diagnosing and treating cancers. Our study investigated the differences in imaging depending on the accumulation of NaYF₄ upconversion nanoparticles (UCNPs) in rat organs (heart, lung, liver, spleen, kidneys) and tumor (liver cancer model), based on their shell type, such as human serum albumin (HSA), HSA with folic acid (HSA+FA), or HSA, FA, and the cyanine dye Cy3 (HSA+FA+Cy3).

We performed simultaneous rapid imaging of NPs using a standard microscope with field-excited luminescence excitation. Histological sections were then prepared according to standard methods, followed by hematoxylin and eosin (H&E) staining.

It was found that NPs accumulated preferentially in tumors. Image processing enabled clear visualization of the accumulation boundaries. These particles may hold promise for future clinical applications, including photodynamic therapy (PDT), due to the observed correlation between particle accumulation and tumor necrosis. When using UCNPs-HSA and UCNPs-HSA+FA, similar changes were detected in rat organs. There were differences in the kidneys depending on the type of particle that was used. When UCNPs-HSA+FA+Cy3 particles were injected into the internal organs, signs of circulatory disorders and minor morphological signs of kidney damage were observed.

The data obtained will enable us to enhance the method of PDT using NPs and a photosensitizer (PS) with additional visualization capabilities.