Preparation Of Tungsten Oxide Quantum Dots And Its Application In Detection Of Telomerase

Telomerase is a DNA reverse transcriptase closely related to cancer.With the increase of cancer incidence and people’s attention to health problems,tumor prevention and early treatment of cancer are becoming more and more important.As one of the biomarkers for early diagnosis of cancer,efficient and highly sensitive detection of the telomerase activity is necessary.The traditional telomerase activity detection method is mainly based on polymerase chain reaction(PCR),but the method needs long time,suffers complicated operation,and can be easily interfered.The fluorescence-based assays have the advantages of simplicity,speed,and high sensitivity.Here we have prepared water-dispersed tungsten oxide quantum dots with umique fluorescent properties by ultrasonic stripping and hydrothermal methods,and then we have proposed a PCR-free fluorescence method for rapid and sensitive detection of telomerase activity based on the inner filter effect(IFE).Transition metal oxides usually demonstrate unique and stable optical properties.Among them,tungsten oxide involves strong designability due to its rich valence states and special crystal configuration.We prepared fluorescent tungsten oxide quantum dots(WOx QDs)by a simple ultrasonic stripping and hydrothermal method.After a series of characterizations,the process and mechanism of the conversion from tungsten sulfide(WS2)powder to WOx QDs were analyzed and verified.The uniform spherical WOx QDs with a diameter of 2.3～2.5 nm involve single crystal structures and stable optical properties.Based on the IFE between WOx QDs and hemin,by using WOx QDs as the fluorescent probes,simple and rapid detection of telomerase activity can be realized.In the presence of telomerase,the primer DNA extends to generate(TTAGGG)n repeat units,and the further formed G-quadruplex encapsulates hemin to reduce its absorbance,thereby reducing IFE and restoring the fluorescent signal of WOx QDs.According to the effect of IFE between hemin and WOx QDs on the fluorescence signal,telomerase activity of tumor cells can be detected,and the detection limit can be down to 17 HeLa cells.This method has good versatility and can also be used to detect telomerase activity in other tumor cells.In addition,due to the good biocompatibility of the sensor,it can also be used to real-time monitor telomerase activity in living cells,showing great potential in tumor diagnosis and screening of telomerase inhibitor drugs.