Fluorescence resonance energy transfer between ZnO/MgO/carboxymethyl-β-cyclodextrin and Nile Red in HeLa cells – biosensing applications

Early diagnosis remains an important problem of cancer treatment strategies. There is therefore a great need for cancer detection tests that are fast, inexpensive and do not require sophisticated laboratory equipment. For this purpose, we synthesized the ZnO/MgO core/shell nanoparticles which are relatively nontoxic, inexpensive and simple to create. We constructed biosensors based on ZnO/MgO nanoparticles which employ the fluorescence resonance energy transfer from ZnO/MgO nanoparticles (donor) to Nile Red (acceptor). Characteristic features of Nile Red luminescence are its solvatochromic and thermochromic properties. In the physiologically relevant temperature range (20-45 degree C), the shift of Nile Red luminescence in the ZnO/MgO/CMCD/Nile Red complex is linear with temperature. In our experiment, thermochromic shift was 5.7 plus or minus 1.5 cm super(-1) K super(-1). Nile Red thermochromism observed in the complex will allow us to construct a sensor capable of detecting exothermic changes and local environmental differences between normal and pathological cells. Subsequently, we studied ZnO/MgO/CMCD/Nile Red complex in vivoin biological samples. We present here, for the first time that the donor-acceptor energy transfer is affected by the intracellular or extracellular locations of the nanoparticles.