A label-free colorimetric sensor based on silver nanoparticles directed to hydrogen peroxide and glucose

Optically activated and interrogated plasmonic hydrogels for applications in wound healing

“…We found that aqueous suspensions of PEGylated Au/Ag core/shell nanorods enjoy substantial stability in an aqueous environment. However, in the presence of H 2 O 2 , Ag shells tend to undergo oxidative dissolution over a time scale that depends on peroxide concentration [30][31][32][33][34][35][36]. In Supporting Information, we give an idea of the kinetics of this reaction, which starts rather slow, but then suddenly accelerates until complete etching of the Ag shell down to its interface with Au.…”

“…Instead, a more substantial transition occurred within the near infrared range pertaining to the longitudinal band, and was invisible to the eye. Compared to the loss of optical absorbance in the blue window that is typical of the oxidative dissolution of Ag nanoparticles [34][35][36], a shift of plasmonic modes within the therapeutic window by few hundreds nanometer is a major advantage in terms of perspectives for optical or hybrid detection, for instance by the use of pulse oximetry, photoacoustic spectroscopy, or more innovative methods, such as terahertz radiation [103]. The detection of small changes of optical absorbance at near infrared frequencies, such as those related to the oxygenation or deoxygenation of hemoglobin [104,105], is a mature achievement in biomedical optics.…”

“…But the combination of optical and redox behavior of these materials may serve even more tasks of interest in wound healing. This is the case for the assessment of oxidative stress by the measurement of the rate of oxidative dissolution of Ag nanoparticles [29][30][31][32][33][34][35][36].…”

“…In spite of its importance, the determination of oxidative stress in vivo is difficult, and has been subject to indirect analyses of oxidation products, such as lipids, proteins or DNA [54,55]. In this context, Ag nanospheres have attracted attention as an ideal case of optical tags, because their rate of oxidative dissolution increases with the environmental concentration of ROS [29][30][31][32][33][34][35][36]. It is unfortunate that the plasmonic band of Ag nanospheres falls in the blue window, which is problematic for biomedical applications and limits the depth of optical penetration to few hundreds microns.…”

Understanding the Interaction of Glutamate Salts with Serum Albumin Protected Prism‐Shaped Silver Nanoparticles toward Glutamate Sensing

“…Selected biological molecules such as amino acids and their derivatives were then added to the Ag@BSA NP solutions and the peak with highest absorbance value (λ max ) in the absorption spectrum was monitored. Figure 1 shows the corresponding relative changes in absorption A Q , as defined by the relative change in absorption upon addition of the biological molecule derivative (A AgNP − A AgNP+molecule ), normalized to the absorption of the NPs [15][16][17][18] What was surprising, at least initially, was the change in LSPR intensity due to MSG addition and therefore further investigations were carried out only to understand such specific MSG-Ag@BSA NPs interactions. MSG shows a clear concentration dependency while interacting with Ag@ BSA NPs.…”