Optical Properties and Cytotoxicity of Quantum Dots
The optical properties exhibited by quantum dots and their unique electronic properties give the new fluorophores various advantages for use as biological dyes, fluorescent proteins, and lanthanide chelators. Quantum dots display a broad emission spectrum allowing excitation over a wide range of wavelengths, a property that can be used to energize numerous quantum dots with unique colors using a single wavelength. Regular colors also have a broad emission spectrum, which means that a wide range of colors can be exhibited to a large extent.
The cytotoxicity of quantum dots has been reported in many in vitro assays, which in turn affects cell development and viability. The degree of cytotoxicity has been found to depend on a variety of factors including size, fluorescence, surface chemistry, and biological activity and processing parameters. Regardless of causing significant changes in cell physiology, quantum dots are capable of causing unobtrusive changes, which may indicate the toxic behavior of the formed quantum dots. These encompass the elution of free cadmium (QD core degradation), the formation of free radicals and the interaction of quantum dots with the internal cellular environment. Recent studies of quantum dot toxicity in a hepatocyte culture model suggest that accumulation of cadmium selenide in the cellular oxidative environment of the core may lead to core degradation and thus elution of cadmium ions.
Molecular Targeting of Quantum Dots
Luminescent quantum dots are a potential alternative to natural dyes for fluorescence-based applications. QDs of transferrin (an iron transporter protein) couples were prepared by covalently binding zinc sulfide-cadmium selenide QDs to proteins with the help of mercaptoacetic acid (MA). When the affixes were fused to HeLa cells, the transferrin particles separated from the receptors on the cell surface and also inside the cells through a receptor-mediated endocytosis mechanism. Previous attempts have been made to apply quantum dots in living cells in vitro. This can allow continuous examination of molecular processes in living cells as well as ligand-receptor interactions.
Theranostics Platform with Quantum Dots
Theranostics is the term given when a system/tool/delivery tool is capable of instantly detecting a disease and its treatment. Warner describes the term as an integrated system/platform that is smart enough to assist in diagnosis and provide treatment for a disease. Nanotherapeutics is now shifting to the concept of therapeutic diagnostics through which coordinated approaches are used to simultaneously treat and check for disease regression. It has resulted in a more sophisticated image-assisted nanotherapy for the treatment of chronic diseases, especially cancer. The distinguishing features of this therapy are its biocompatibility, reduced side effects and reduced risk of affecting healthy human cells.
