Intraoperative staining of malignant lung tumors using bioorganic fluorescent gold nanoclusters bound to aptamers

Background: The problem of recurrence, generalization, or metastasis of lung cancer remains relevant to this day, despite the advances in diagnostic and therapeutic methods of treatment. The main method of localized lung cancer treatment is surgery. The volume of resection is determined by the location of the tumor, its spread to surrounding tissues and the status of lymph node damage. However, even after removal of a large part of the lung, metastatic foci may remain in healthy tissue. To improve the effectiveness of diagnostics during surgery, fluorescence-navigated surgery can be used, based on the use of fluorescent dyes, which enables to see even small clusters of malignant cells in the early stages of tumor process development. Aim: To develop a drug for fluorescence-navigation surgery based on aptamers and fluorescent gold nanoclusters (fluorescence excitation wavelengths are 365–410 nm, emission wavelengths are 615–650 nm). Materials and Methods: The object of the study is primary cultures of non-small cell lung cancer. Liposomes functionalized with DNA aptamer LC-17 were used to deliver gold nanoclusters stabilized with glutathione (GSH-AuNC) or bovine serum albumin (BSA-AuNC) to lung cancer cells. Electron microscopic images of the synthesized nanoclusters were obtained using transmission electron microscopy. Analysis of the efficiency of tumor cell binding to aptamer-functionalized liposomes containing nanoclusters was performed using flow cytometry Lung adenocarcinoma tissue was used to evaluate the efficiency of fluorescent nanoclusters. Results: The diameter of BSA-AuNC and GSH-AuNC nanoclusters was 1.8±0.5 nm and 1.5±0.3 nm, respectively. When exciting by light with a wavelength of 365 nm, the maximum fluorescence emission for BSA-AuNCs was 655 nm, and for GSH-AuNCs — 613 nm. The fluorescence quantum yields for BSA-AuNCs and GSH-AuNCs were 6% and 14%, respectively. LC-17 aptamer-functionalized liposomes with included GSH-AuNC and BSA-AuNC effectively bound to lung adenocarcinoma cells and stained them. Conclusion: The possibilityl of using gold nanoclusters stabilized by GSH-AuNC and BSA-AuNC for fluorescence-guided surgery is demonstrated.