Novel nanoscale bioconjugates combining unique plasmonic photothermal properties of gold nanoparticles (AuNPs) with targeted delivery using cell-specific DNA aptamers have a tremendous potential for medical diagnostics and therapy of many cell-based diseases. In this study, we demonstrate the high anti-cancer activity of aptamer-conjugated, 37-nm spherical gold nanoparticles toward Ehrlich carcinoma in tumor-bearing mice after photothermal treatment. The synthetic anti-tumor aptamers bring the nanoparticles precisely to the desired cells and selectively eliminate cancer cells after the subsequent laser treatment. To prove tumor eradication, we used positron emission tomography (PET) utilizing radioactive glucose and computer tomography, followed by histological analysis of cancer tissue. Three injections of aptamer-conjugated AuNPs and 5 min of laser irradiations are enough to make the tumor undetectable by PET. Histological analysis proves PET results and shows lower damage of healthy tissue in addition to a higher treatment efficiency and selectivity of the gold nanoparticles functionalized with aptamers in comparison to control experiments using free unconjugated nanoparticles.

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Identification of primary tumors and metastasis sites is an essential step in cancer diagnostics and the following treatment. Positron emission tomography-computed tomography (PET/CT) is one of the most reliable methods for scanning the whole organism for malignancies. In this work, we synthesized an 11 C-labeled oligonucleotide primer and hybridized it to an anti-cancer DNA aptamer. The 11 C-aptamer was applied for in vivo imaging of Ehrlich ascites carcinoma and its metastases in mice using PET/CT. The imaging experiments with the 11 C-aptamer determined very small primary and secondary tumors of 3 mm 2 and less. We also compared 11 C imaging with the standard radiotracer, 2-deoxy-2-[fluorine-18]fluoro-Dglucose ( 18 F-FDG), and found better selectivity of the 11 C-aptamer to metastatic lesions in the metabolically active organs than 18 F-FDG. 11 C radionuclide with an ultra-short (20.38 min) half-life is considered safest for PET/CT imaging and does not cause false-positive results in heart imaging. Its combination with aptamers gives us high-specificity and high-contrast imaging of cancer cells and can be applied for PET/CT-guided drug delivery in cancer therapies.

The aim of the research. An intensive research is underway to create new methods for the synthesis of fl uorine-18 labeled radiopharmaceuticals. Th e aim of this work is to select iodoaliphatic carboxylic acids and esters for radiopharmaceuticals labeling. Material and methods. A simple way to obtain z-yodalifi c carbonic acids and complex esters from commercially available cyclic ketones has been developed. Automatic synthesis of 18F-fl uoroproprostatic groups and 18F fl uoride peptide agents is successfully carried out using new original materials and various purifi cation methods with solid phase cartridges Results. In further work, it is planned to use diff erent 18F-fl uoroproproprostatic groups for synthesis with various peptide agents. Conclusion. Based on these compounds 18F-fl uoroproproprostatic groups were synthesized. Octreotid as an analogue of somatostatin, the non-immunoglobulin-specifi c frame proteins (designed ankyrin repeat proteins) for targeted imaging of tumor cells hyperexpressing Her-2/neu, and prostate-specifi c membrane antigen (PSMA) inhibitor are signifi cant peptide agents.

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