The Synthesis Of Luminescent Carbon Nanoparticles And The Applications In Biochemical Analysis

Fluorescent carbon nanoparticles is a kind of carbon nanoparticles (CNPs) whose skeleton structure is based on carbon, and of which at least in one dimension is smaller than 100 nm, approximately spherical particles, and of which is less than 10 nm, also known as carbon dots. Because of the excellent fluorescent properties,, semiconductor quantum dots (QDs) have attracted much attention for their applications in the biological and medical fields, but QDs containing heavy metal ions which are toxic to living cells and have light blinking phenomenon. The CNPs’s main constituent elements are carbon with higher oxygen, major amounts of carbon with higher oxygen contents, so CNPs have a low toxicity and good bio compatibility, it is possible the best choice to replace semiconductor quantum dots, a lot of methods have been developed to synthesize carbon nanoparticles by using biological materials as carbon sources. But at present how to control the morphology of carbon nanoparticles and the influence of the precursor on the synthesis of carbon nanoparticles luminous performance, is still in a state of blank. This paper embarks from the biological material for synthesis of good biocompatibility of carbon nanoparticles, including the following specific content.The nitrogen and sulfur co-doped CNPs have been synthesized by one-step hydrothermal treatment of millet without any additives, such as acids or bases. The as-obtained CNPs possess uniform and amorphous morphology with the amount of particle size distribution is between 32 and 92 nm, the average particle size of 56 nm, Its surface is rich in hydroxyl and carboxyl groups, making the CNPs water-soluble and excellent and stable fluorescent properties with a QY of ca.30.4%. The CNPs has good resistance to light bleaching ability and low cytotoxicity, the ionic strength almost has no effect on the photoluminescence (PL) intensity, and can be applied to cell imaging. The CNPs could serve as new fluorescent probes for the detection of iron ions, the linear range of 2.5 to 20μM, linear correlation coefficient (r) was 0.9992. The dynamic light scattering showed the hydrodynamic size of the CNPs hardly changed after the addition of Fe3+, which suggestd that no aggregation occurred. And the PL intensity of the CNPs within a certain range of pH sensitive, and with the increase of pH value increases, the linear response range of pH values of 5-9, the the linear correlation coefficient (r) was 0.9961,and there is hope that the CNPs could be utilized as intracellular pH sensor.