Aptamers and nanoparticles as a potential platform for the diagnosis and treatment of cancer

The presented PhD thesis is divided into two thematic parts. The first is dedicated to synthetic DNA aptamers and their application in biosensors for protein detection. We focused on thrombin and cytochrome c (cyt c) binding aptamers. The thrombin binding aptamer was modified with fluorescent dye TAMRA in hairpin structure of the molecular beacon (TBA-TG). Interaction of TBA-TG with thrombin has studied by fluorescent method. TBA-GT was also immobilized on gold substrates via thiols groups by chemisoprtion. We achieved the limit of detection (LOD) for TBA-TG in solution LOD= 10,79 nM, in case of aptamers immobilized on gold substrate and in presence of 50 mM KCl we obtained substantially lower LOD=0,61 nM. We studied also electrochemical detection of cyt c by using biosensors based on DNA aptamers (apt 76) immobilized on the gold electrode via PAMAM G4 dendrimers to prevent nonspecific interactions due to electroactive nature of cyt c. Limit of detection LOD = 5 ± 0,05 nM was achieved, but reproducibility was low, probably due to length of apt 76 and not complete protection of interaction of cyt c with gold. In the second part of thesis, we concentrated on polyalkylcyanoacrylate nanoparticles as potential tool for drug delivery. We studied cytotoxic effect of polybutylcyanoacrylate (PBCA) and polyoctylcyanoacrylate (POCA) nanoparticles with encapsulated and free drug cabazitaxel on human mammary adenocarcinoma cell lines (MDA-MB-231) and glioblastoma (P3) by Alamar Blue assay. Cabazitaxel, which acts in cells as inhibitor of mitotic division, showed higher cytotoxic effect for P3 cells. Interaction of nanoparticles with model lipid membranes- Langmuir monolayers was also studied. (Author)