Gold nanorod photoluminescence : applications to imaging and temperature sensing

Gold nanorods are ideal candidates for complementing fluorophores in labelling applications. The presence of the surface plasmon resonance generates large absorption and scattering cross sections, thus making the detection of single nanoparticles possible under a light microscope. The plasmon of gold nanorods depends on the ratio between their width and length and covers the range between 540nm for spheres and even above 800nm for elongated particles, thus almost the entire visible and near-infrared spectrum. The surface plasmon presents great opportunities in (bio-)sensing, enhanced spectroscopies, photothermal therapy and for concentrating light below the diffraction limit.Biological and Soft Matter Physic

Gold nanorod photoluminescence : applications to imaging and temperature sensing

Gold nanorods are ideal candidates for complementing fluorophores in labelling applications. The presence of the surface plasmon resonance generates large absorption and scattering cross sections, thus making the detection of single nanoparticles possible under a light microscope. The plasmon of gold nanorods depends on the ratio between their width and length and covers the range between 540nm for spheres and even above 800nm for elongated particles, thus almost the entire visible and near-infrared spectrum. The surface plasmon presents great opportunities in (bio-)sensing, enhanced spectroscopies, photothermal therapy and for concentrating light below the diffraction limit.</p

Kallikrein-like amidase activity in renal ischemia and reperfusion

We assessed a kallikrein-like amidase activity probably related to the kallikrein-kinin system, as well as the participation of leukocyte infiltration in renal ischemia and reperfusion. Male C57BL/KSJmdb mice were subjected to 20 or 60 min of ischemia and to different periods of reperfusion. A control group consisted of sham-operated mice, under similar conditions, except for ischemia induction. Kallikrein-like amidase activity, Evans blue extravasation and myeloperoxidase activity were measured in kidney homogenates, previously perfused with 0.9% NaCl. Plasma creatinine concentration increased only in the 60-min ischemic group. After 20 min of ischemia and 1 or 24 h of reperfusion, no change in kallikrein-like amidase activity or Evans blue extravasation was observed. In the mice subjected to 20 min of ischemia, edema was evident at 1 h of reperfusion, but kidney water content returned to basal levels after 24 h of reperfusion. In the 60-min ischemic group, kallikrein-like amidase activity and Evans blue extravasation showed a similar significant increase along reperfusion time. Kallikrein-like amidase activity increased from 4 nmol PNA mg protein-1 min-1 in the basal condition to 15 nmol PNA mg protein-1 min-1 at 10 h of reperfusion. For dye extravasation the concentration measured was near 200 µg of Evans blue/g dry tissue in the basal condition and 1750 µg of Evans blue/g dry tissue at 10 h of reperfusion. No variation could be detected in the control group. A significant increase from 5 to 40 units of DAbs 655 nm g wet tissue-1 min-1 in the activity of the enzyme myeloperoxidase was observed in the 60-min ischemic group, when it was evaluated after 24 h of reperfusion. Histological analysis of the kidneys showed migration of polymorphonuclear leukocytes from the vascular bed to the interstitial tissue in the 60-min ischemic group after 24 h of reperfusion. We conclude that the duration of ischemia is critical for the development of damage during reperfusion and that the increase in renal cortex kallikrein-like amidase activity probably released from both the kidney and leukocytes may be responsible, at least in part, for the observed effects, probably through direct induction of increased vascular permeability

Challenges of implementing nano-specific safety and safe-by-design principles in academia

Safe-by-design is an essential component for creating awareness of the potential novel risks associated with the introduction of sophisticated nanomaterials (NMs) with novel properties. SbD is also a useful tool for meeting EU policy ambitions such as the European Green Deal which includes circular economy and moving towards a zero pollution (pollution-free) environment. Unidentified risks are a growing concern with the rapid and exponential advances of nanotechnology innovation, and the increase in fundamental research on NMs and their potential applications. Therefore, addressing nano-specific safety issues early in the innovation process is vital for reducing the uncertainties of novel NMs. The challenge is that many innovators and material scientists are not toxicologist and are not aware on how to assess the safety of their innovations and novel materials. Safe-by-design is a concept that aims at reducing uncertainties and risks for humans and the environment, starting at an early phase of the innovation process and covering the whole innovation value chain, including research. This perspective tries to get a better understanding on the role of safe-by-design within engineered nanomaterial research to create awareness on the importance on assessing the safety early in research. A method was developed that integrates SbD with a set of questions to aid material scientists assess the safety of their materials (nano-specific safety aspects) and Risk Analysis and Technology Assessment (RATA). Here we present the results of a workshop for material scientists (PhD students) with limited toxicology knowledge at the Debye Institute for Nanomaterials Science (Utrecht University, The Netherlands) with the main goals to create awareness with regard to basic NM safety and to explore the possibilities for applying safe-by-design principles in academia. The approach presented here can be applied by researchers and innovators to assess the safety of NMs at an early stage of the innovation process, and this work is framed in the context of Responsible Research and Innovation using RATA

Challenges of implementing nano-specific safety and safe-by-design principles in academia

Safe-by-design is an essential component for creating awareness of the potential novel risks associated with the introduction of sophisticated nanomaterials (NMs) with novel properties. SbD is also a useful tool for meeting EU policy ambitions such as the European Green Deal which includes circular economy and moving towards a zero pollution (pollution-free) environment. Unidentified risks are a growing concern with the rapid and exponential advances of nanotechnology innovation, and the increase in fundamental research on NMs and their potential applications. Therefore, addressing nano-specific safety issues early in the innovation process is vital for reducing the uncertainties of novel NMs. The challenge is that many innovators and material scientists are not toxicologist and are not aware on how to assess the safety of their innovations and novel materials. Safe-by-design is a concept that aims at reducing uncertainties and risks for humans and the environment, starting at an early phase of the innovation process and covering the whole innovation value chain, including research. This perspective tries to get a better understanding on the role of safe-by-design within engineered nanomaterial research to create awareness on the importance on assessing the safety early in research. A method was developed that integrates SbD with a set of questions to aid material scientists assess the safety of their materials (nano-specific safety aspects) and Risk Analysis and Technology Assessment (RATA). Here we present the results of a workshop for material scientists (PhD students) with limited toxicology knowledge at the Debye Institute for Nanomaterials Science (Utrecht University, The Netherlands) with the main goals to create awareness with regard to basic NM safety and to explore the possibilities for applying safe-by-design principles in academia. The approach presented here can be applied by researchers and innovators to assess the safety of NMs at an early stage of the innovation process, and this work is framed in the context of Responsible Research and Innovation using RATA