As a typical plant virus which has biocompatibility and high transfection efficiency,tobacco mosaic virus(TMV)has shown broad application potential in drug or gene delivery field.Elucidating its intracellular traffick...As a typical plant virus which has biocompatibility and high transfection efficiency,tobacco mosaic virus(TMV)has shown broad application potential in drug or gene delivery field.Elucidating its intracellular trafficking is of great importance in investigation of its cytotoxicity,targeting site,and delivery efficiency,and is advantageous to designing new TMV-based drug delivery systems with different targets.By taking advantage of the regulated pH value of different organelles in a mammalian cell,we exploit a pH detection strategy to investigate the intracellular trafficking pathway of TMV.Here,we report a single-wavelength excited ratiometric fluorescent pH probe.This probe is constructed by simultaneously coupling pH-sensitive fluorescein isothiocyanate(FITC)and pH-insensitive rhodamine B isothiocyanate(RBIRC)onto the inner surface of TMV.The fluorescence intensity ratio of FITC to RBITC excited at 488 nm responds specifically towards pH value over other interferential agents.By taking use of this single-wavelength excited ratiometric pH probe and confocal laser scanning microscopy,it is shown that the endocytosed TMV is located in a pH decreasing microenvironment and eventually enters lysosomes.This work may provide important guidance on construction of TMV-based nano carriers.展开更多
A diode-triggered silicon controlled rectifier (DTSCR) is being developed as an electrostatic discharge (ESD) pro- tection device for low voltage applications. However, DTSCR leaks high current during normal operation...A diode-triggered silicon controlled rectifier (DTSCR) is being developed as an electrostatic discharge (ESD) pro- tection device for low voltage applications. However, DTSCR leaks high current during normal operation due to the Darlington effect of the triggering-assist diode string. In this study, two types of diode string triggered SCRs are designed for low leakage consideration; the modified diode string and composite polysilicon diode string triggered SCRs (MDTSCR & PDTSCR). Com- pared with the conventional DTSCR (CDTSCR), the MDTSCR has a much lower substrate leakage current with a relatively large silicon cost, and the PDTSCR has a much lower substrate leakage current with similar area and shows good leakage performance at a high temperature. Other DTSCR ESD properties are also investigated, especially regarding their layout, triggering voltage and failure current.展开更多
基金the National Key R&D Program of China(No.2018YFC1105300)the National Natural Science Foundation of China(Nos.51703230 and 21776021)+3 种基金the Bejjing Natural Science Foundation(No.7182110)the Cross Training Plan for High Level Talents in Beiingthe Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2017039)the Presidential Foundation of Technical Institute of Physics and Chemistry.
文摘As a typical plant virus which has biocompatibility and high transfection efficiency,tobacco mosaic virus(TMV)has shown broad application potential in drug or gene delivery field.Elucidating its intracellular trafficking is of great importance in investigation of its cytotoxicity,targeting site,and delivery efficiency,and is advantageous to designing new TMV-based drug delivery systems with different targets.By taking advantage of the regulated pH value of different organelles in a mammalian cell,we exploit a pH detection strategy to investigate the intracellular trafficking pathway of TMV.Here,we report a single-wavelength excited ratiometric fluorescent pH probe.This probe is constructed by simultaneously coupling pH-sensitive fluorescein isothiocyanate(FITC)and pH-insensitive rhodamine B isothiocyanate(RBIRC)onto the inner surface of TMV.The fluorescence intensity ratio of FITC to RBITC excited at 488 nm responds specifically towards pH value over other interferential agents.By taking use of this single-wavelength excited ratiometric pH probe and confocal laser scanning microscopy,it is shown that the endocytosed TMV is located in a pH decreasing microenvironment and eventually enters lysosomes.This work may provide important guidance on construction of TMV-based nano carriers.
基金Project partially supported by the Zhejiang Provincial Nature Science Fund of China (Nos. Y107055 and Y1080546)the Semiconductor Manufacturing International Corp. (SMIC)
文摘A diode-triggered silicon controlled rectifier (DTSCR) is being developed as an electrostatic discharge (ESD) pro- tection device for low voltage applications. However, DTSCR leaks high current during normal operation due to the Darlington effect of the triggering-assist diode string. In this study, two types of diode string triggered SCRs are designed for low leakage consideration; the modified diode string and composite polysilicon diode string triggered SCRs (MDTSCR & PDTSCR). Com- pared with the conventional DTSCR (CDTSCR), the MDTSCR has a much lower substrate leakage current with a relatively large silicon cost, and the PDTSCR has a much lower substrate leakage current with similar area and shows good leakage performance at a high temperature. Other DTSCR ESD properties are also investigated, especially regarding their layout, triggering voltage and failure current.
