Synthesis Of Carbon Nanodots And Their Application In Cancer Theranostic And Temperature Phosphorescence

Carbon nanodots?CDs?are considered as emerging nanomaterials for advanced biomedical applications and data encryption attributing to their high biocompatibility,low-cost,and unique photophysical properties.CDs have great development over the past decade,but now there remains key obstacle to using them as an in vivo theranostic agent,and the application of phosphorescence performance,mainly in the following problems unsolved:?1?The absorption coefficients and fluorescence intensity of these reported CDs were significantly reduced in long wavelength region?red-to-NIR region?.?2?Almost no kind of CDs which have reported could accumulated at the tumor sites in vivo.?3?The performance of phosphorescence from CDs and their composites are un-tunable.In this paper we synthesized three kinds of CDs,furthermore applied these CDs in in vivo tumor diagnosis/treatment and phosphorescence data encryption,the details are as follows:1.Supra-?Carbon nanodots?with high photothermal conversion efficiency?52%?and high absorption intensity at long wavelength region was synthesized via the self-assemble of blue emissive CDs.Supra-?Carbon nanodots?are explored as a photothermal agent for photothermal therapy?PTT?and a contrast agent for photoacoustic?PA?imaging,respectively.Supra-?Carbon nanodots?can accumulate in the tumor tissue via the blood circulation after intravenous injection,so in vivo tumor diagnosis via PA imaging was realized.Moreover,in vivo tumor PTT is realized under655 nm laser irradiation(power density is 1W cm^-2)via intratumor injecting supra-CNDs.2.A novel sulfur and nitrogen codoped carbon nanodots with high photothermal conversion efficiency?59%?,high absorption intensity and fluorescence emission at long wavelength region was synthesized.Contrary to all other nanomaterials that have been tested in biomedicine,they are excreted through the body's renal filtration system.Moreover,after intravenous injection,CDs are accumulated in tumor tissue via passive targeting,without any active species.With the ability of fluorescence/PA imaging and high photothermal conversion efficiency,in vivo tumor diagnosis via fluorescence/PA imaging and in vivo tumor PTT were realized,respectively.Based on these advantages,NIR CDs are suitable for transfer to clinical biomedical practice.3.CD@PVA?polyvinyl alcohol?composite with room temperature phosphorescence processes was synthesized,and the control of the phosphorescent signal is realized.Enhanced green phosphorescence is obtained via thermal annealing of the composite under 200°C,which can be quenched via water treatment,and then recovered again,via either repeated annealing or NIR laser irradiation.Water molecules infiltrating the CD/PVA composite lead to considerable vibrational motions of the CD surface groups through destruction of the rigid composite structure together with an increase in the possibility of the penetration of the phosphorescence quenchers,and thus a decrease in the phosphorescence intensity.After repeated annealing,the nonradiative transitions are restricted,and the phosphorescence signal is recovered again.Based on such“on–off”switching of the phosphorescence signal,some concepts of multiple data encryption are realized by using the CD@PVA composite.