In this work,silver(Ag)nanocubes with different sizes were rapidly synthesized with a modified HClbased polyol approach by employing carbamide(CO(NH_(2))_(2))as the additive or promoter,which could shorten the reactio...In this work,silver(Ag)nanocubes with different sizes were rapidly synthesized with a modified HClbased polyol approach by employing carbamide(CO(NH_(2))_(2))as the additive or promoter,which could shorten the reaction time from about 25 h to less than 4 h and the method could be confirmed as facile and robust.In the reaction system,the NH3 molecules play the role of aggregating Ag^(+)and[Ag(NH_(3))_(2)]^(+)could gradually release Ag^(+),which in turn results in formation of a more homogeneous product in a short time(50 min-4 h).Some factors affecting the synthesis including the concentration,reaction time and agitator speed have also been investigated,which could be adjusted to control the size,morphology,purity and uniformity of the Ag nanocubes.A mechanism for the rapid synthesis of the Ag nanocubes was proposed.To overcome the lower repeatability of reported methods,we have supplied a robust method to synthesize Ag nanocubes and this procedure may provide a useful guide for the future synthesis of Ag or other metal nanoparticles.The transmittance properties of the different Ag nanocubes have also been detected,which demonstrated that the transmittance of the Au film coupled with the Ag nanocubes is very sensitive to not only the size of the Ag nanocubes but also the thickness of the polyelectrolyte molecular spacer layers.展开更多
Capacitively coupled shortwave radiofrequency fields(13.56 MHz)resistively heat low concentrations(~1 ppm)of gold nanoparticles with a thermal power dissipation of~380 kW/g of gold.Smaller diameter gold nanoparticles(...Capacitively coupled shortwave radiofrequency fields(13.56 MHz)resistively heat low concentrations(~1 ppm)of gold nanoparticles with a thermal power dissipation of~380 kW/g of gold.Smaller diameter gold nanoparticles(<50 nm)heat at nearly twice the rate of larger diameter gold nanoparticles(≥50 nm),which is attributed to the higher resistivity of smaller gold nanostructures.A Joule heating model has been developed to explain this phenomenon and provides critical insights into the rational design and engineering of nanoscale materials for noninvasive thermal therapy of cancer.展开更多
基金supported by the Natural Science Foundation of China(NSFC no.21471103,21471100,51002180,21001074,20731002,20871016,10876002,91022006 and 20973023)the 111 Project(B07012)+1 种基金the Project of Excellent Talents of Beijing(203135407707)the Scientific Research Base Development Program of the Beijing Municipal Commission of Education.
文摘In this work,silver(Ag)nanocubes with different sizes were rapidly synthesized with a modified HClbased polyol approach by employing carbamide(CO(NH_(2))_(2))as the additive or promoter,which could shorten the reaction time from about 25 h to less than 4 h and the method could be confirmed as facile and robust.In the reaction system,the NH3 molecules play the role of aggregating Ag^(+)and[Ag(NH_(3))_(2)]^(+)could gradually release Ag^(+),which in turn results in formation of a more homogeneous product in a short time(50 min-4 h).Some factors affecting the synthesis including the concentration,reaction time and agitator speed have also been investigated,which could be adjusted to control the size,morphology,purity and uniformity of the Ag nanocubes.A mechanism for the rapid synthesis of the Ag nanocubes was proposed.To overcome the lower repeatability of reported methods,we have supplied a robust method to synthesize Ag nanocubes and this procedure may provide a useful guide for the future synthesis of Ag or other metal nanoparticles.The transmittance properties of the different Ag nanocubes have also been detected,which demonstrated that the transmittance of the Au film coupled with the Ag nanocubes is very sensitive to not only the size of the Ag nanocubes but also the thickness of the polyelectrolyte molecular spacer layers.
基金the Radiowave Therapy Fund and Institutional Core Grant#CA16672 High-Resolution Electron Microscopy Facility,UTMDACC.The authors are grateful to Richard E.Smalley,Boris Yakobson,Bruce Johnson,Robert Curl,and George M.Whitesides for helpful discussions and suggestions.The authors are also grateful to Nanospectra Biosciences, Inc., Donald Payne, and Glenn Goodrich for providing gold nanoshell samples and Precision Colloids, LLC for providing silica samples.
文摘Capacitively coupled shortwave radiofrequency fields(13.56 MHz)resistively heat low concentrations(~1 ppm)of gold nanoparticles with a thermal power dissipation of~380 kW/g of gold.Smaller diameter gold nanoparticles(<50 nm)heat at nearly twice the rate of larger diameter gold nanoparticles(≥50 nm),which is attributed to the higher resistivity of smaller gold nanostructures.A Joule heating model has been developed to explain this phenomenon and provides critical insights into the rational design and engineering of nanoscale materials for noninvasive thermal therapy of cancer.
