For the first time, we are reporting a novel type of dual fluorescence temperaturesensitive DNA-templated silver nanocluster （AgNC） pair, which contains two pieces of single-stranded AgNC in proximity through hybrid...For the first time, we are reporting a novel type of dual fluorescence temperaturesensitive DNA-templated silver nanocluster （AgNC） pair, which contains two pieces of single-stranded AgNC in proximity through hybridization. Both the chameleon AgNC pairs, A-NCP and B-NCP, possess two bright fluorescence peaks that achieve sensitive variations corresponding to temperature change from 15 to 45 ℃. With the increase in temperature, one of the fluorescence emissions of A-NCP （A-FL570） increases, while the other （A-FL640） decreases. However, both the emissions of B-NCP （B-FL685 and B-FL620） decrease simultaneously. Therefore, A-NCP shows a remarkable fluorescence color variation from orange to yellow, while the fluorescence color of B-NCP changes from orange to colorless, with increase in temperature. Moreover, the temperature responding linear range of A-NCP can be regulated by adjusting the structures and sequences of assistant DNA templates. It is assumed that the two single-stranded segmental AgNCs are integrated together as they are assembled into AgNC pairs, leading to a dramatic variation in fluorescence properties. The temperature-sensitive phenomenon is due to the dehybridization-induced separation of two pieces of segmental AgNC, caused by temperature increase. The temperature-sensitive AgNC pairs have been successful in indicating the temperature of living cells, showing the potential for a new application of silver nanocluster as a nanothermometer with adjustable response range, bringing novel insight into the regulatory mechanism of AgNC fluorescence variation.展开更多
Enhanced cellular uptake efficiency of nanoparticles is important for their biomedical applications, including photothermal therapy （PTT） for cancer. In this study, a one-pot method was used to construct a positivel...Enhanced cellular uptake efficiency of nanoparticles is important for their biomedical applications, including photothermal therapy （PTT） for cancer. In this study, a one-pot method was used to construct a positively charged and magnet-responsive nanocomposite comprising reduced graphene oxide anchoring iron oxide （RGI） with a polyethylenimine （PEI） modification, to improve the efficiency of cell internalization. The surface charge can be finely tuned using PEIs of different molecular weights. The obtained RGIlsk composite （RGI modified by 1.8 kDa PEI） could load indocyanine green （ICG） at a high mass ratio of 10：3 and ablate cancer cells using low-density laser irradiation because of its positively charged surface. In addition, the hybrids of RGI1.8k and ICG could kill most cancer cells at a laser density of 0.7 W/cm2 in vitro and 0.3 W/cm2 in vivo. At the same time, cell viability could be controlled by converting the external magnetic-field direction because of the enrichment of the magnet-responsive composite in vitro and in vivo. Furthermore, RGIr8k-ICGs could be used as T2-weighted magnetic resonance and infrared thermal imaging agents. Coupled with the magnetic target effect, the imaging signal could be improved significantly. Therefore, RGII^sk-ICGs represent a new highly efficient PTT and imaging agent with great potential for cancer treatment.展开更多
基金This work was supported by National Natural Science Foundation of China （No. 21375123） and The Ministry of Science and Technology of China （No. 216YFA0203201）.
文摘For the first time, we are reporting a novel type of dual fluorescence temperaturesensitive DNA-templated silver nanocluster （AgNC） pair, which contains two pieces of single-stranded AgNC in proximity through hybridization. Both the chameleon AgNC pairs, A-NCP and B-NCP, possess two bright fluorescence peaks that achieve sensitive variations corresponding to temperature change from 15 to 45 ℃. With the increase in temperature, one of the fluorescence emissions of A-NCP （A-FL570） increases, while the other （A-FL640） decreases. However, both the emissions of B-NCP （B-FL685 and B-FL620） decrease simultaneously. Therefore, A-NCP shows a remarkable fluorescence color variation from orange to yellow, while the fluorescence color of B-NCP changes from orange to colorless, with increase in temperature. Moreover, the temperature responding linear range of A-NCP can be regulated by adjusting the structures and sequences of assistant DNA templates. It is assumed that the two single-stranded segmental AgNCs are integrated together as they are assembled into AgNC pairs, leading to a dramatic variation in fluorescence properties. The temperature-sensitive phenomenon is due to the dehybridization-induced separation of two pieces of segmental AgNC, caused by temperature increase. The temperature-sensitive AgNC pairs have been successful in indicating the temperature of living cells, showing the potential for a new application of silver nanocluster as a nanothermometer with adjustable response range, bringing novel insight into the regulatory mechanism of AgNC fluorescence variation.
基金The work was supported by the National Natural Science Foundation of China （Nos. 31301177, 21427811, and 91430217）, and MOST China （No. 2013YQ170585）. J. W. also appreciated NSF.
文摘Enhanced cellular uptake efficiency of nanoparticles is important for their biomedical applications, including photothermal therapy （PTT） for cancer. In this study, a one-pot method was used to construct a positively charged and magnet-responsive nanocomposite comprising reduced graphene oxide anchoring iron oxide （RGI） with a polyethylenimine （PEI） modification, to improve the efficiency of cell internalization. The surface charge can be finely tuned using PEIs of different molecular weights. The obtained RGIlsk composite （RGI modified by 1.8 kDa PEI） could load indocyanine green （ICG） at a high mass ratio of 10：3 and ablate cancer cells using low-density laser irradiation because of its positively charged surface. In addition, the hybrids of RGI1.8k and ICG could kill most cancer cells at a laser density of 0.7 W/cm2 in vitro and 0.3 W/cm2 in vivo. At the same time, cell viability could be controlled by converting the external magnetic-field direction because of the enrichment of the magnet-responsive composite in vitro and in vivo. Furthermore, RGIr8k-ICGs could be used as T2-weighted magnetic resonance and infrared thermal imaging agents. Coupled with the magnetic target effect, the imaging signal could be improved significantly. Therefore, RGII^sk-ICGs represent a new highly efficient PTT and imaging agent with great potential for cancer treatment.
