CHARACTERIZATION OF FLUORESCENT CARBON DOTS FOR SENSORS CONCTRUCTION

Carbon dots (C-dots) are a new type of nanomaterial broadly used in sensing, imaging and distinct analytical applications. They possess several advantages over classical semiconductor quantum dots like higher biocompatibility and lower toxicity. In this study C-dots were successfully synthesized from citric acid as a carbon source and covered with poly-(ethylene glycol). Since precise nanoparticle characterization represents the key step in nanosensor construction, C-dots were characterized using several methods - UV/vis spectrophotometry, fluorescence spectroscopy, dynamic light scattering and electrochemistry. In C-dots absorption spectra with two local maxima at 280 and 330 nm corresponding to n-pi* and pi-pi* transition were observed. The maximal fluorescence of 2 +/- 0.5 nm sized C-dots were reached using excitation wavelength of 370 nm. The electrochemical analysis of C-dots using HMDE in Brdicka solution suggested, that this method can be used to determine the amount of PEG capping agent on the surface of C-dots nanocrystals.