| Abstract [eng] |
Investigation of the Potential use of CuInS2/ZnS Quantum Dots for Brain Cancer Diagnostics During the search for new ways to diagnose and treat cancer, including nervous system cancer, optical methods, such as fluorescence spectroscopy or photodynamic therapy, have emerged as viable alternatives to MRI, radiotherapy and other currently used methods. Such methods require the use of certain organic compounds, namely fluorescent dyes and photosensitizers, and their disadvantages, such as lack of stability in biological environments, hydrophobicity and generally low efficiency, are preventing wider application of optical methods. Use of nanomaterials, like quantum dots (QDs), is one way to improve on these aspects, either by using QDs by themselves or by conjugating them with various other compounds. Their one drawback is possible nanotoxicity, as most widely used QDs contain toxic elements, such as cadmium or lead. This could be circumvented by using heavy metal-free QDs, such as ones composed of CuInS2. As the use of these QDs for cancer theranostics in general is not well investigated, it was decided to investigate their potential as brain cancer theranostic agents. Optical and physicochemical properties of CuInS2/ZnS core/shell QDs functionalized with amine or carboxyl groups were determined using absorption and fluorescence spectroscopy, atomic force microscopy and dynamic light scattering methods and were found to be suitable for brain cancer theranostics. Stability of photoluminescence intensity and fluorescence lifetime of both types of QDs over one week was investigated in PBS and DMEM media. aQDs were found to be more stable in PBS, while stability of cQDs was better in DMEM. During the practically important time period of 24 h, stability of both aQDs and cQDs was sufficient for medical applications. Lastly, accumulation of aQDs in MDA-MB-231 breast cancer cells and cQDs in U87 glioblastoma cells was investigated. Results show increasing concentration of QDs inside cells with longer incubation periods, localization of QDs in vesicular structures and more efficient accumulation in serum-free media. cQDs also were shown to not have a negative impact on U87 cell viability. Results of these experiments show the potential of CuInS2 QDs for applications in brain cancer theranostics, although further studies are required to bring them closer to clinical use. |
