Green and Orange Fluorescent Carbon Dots for Detecting Oral Cancer by Staining Tissue Sections

By using ethylenediamine (ED) with nitric acid (NA) and formic acid (FA) as raw materials, two types of new carbon dots (CDs) were prepared using microwave method. The as-prepared CDs showed excellent water solubility and photoluminescence properties. The optimum excitation wavelength and emission wavelength of new CDs were at 430 nm and 500 nm (for CDs fabricated with ED and NA) and at 480 nm and 570 nm (for CDs synthesized with ED and FA), respectively. Dyeing the oral tissue with these new CDs was found to be an effective means to stain oral tissue sections. The cell morphology and distribution of the oral tissues can be clearly observed under a fluorescence microscopy. Compared with the hematoxylin-eosin (HE) staining method, a common staining method in biopsy, the dyeing operation of the new CDs is simpler with clearer imaging effect. The difference in cell morphology and distribution between normal oral tissues and pathological oral tissues was observed under a fluorescence microscope by CDs staining to distinguish normal tissues from pathological tissues. Thus, a novel method for detecting oral cancer was developed.