The photothermal generation of nanoscale vapor bubbles around noble metal nanoparticles is of significant interest, not only in understanding the underlying mechanisms responsible for photothermal effects, but also to optimize photothermal effects in applications such as photothermal cancer therapies. Here, we describe the dynamics in the 400-900 nm regime of the formation and evolution of nanobubbles around colloidal gold nanoparticles using picosecond pump-probe optical measurements. From excitations of 20-150 nm colloidal gold nanoparticles with a 355 nm, 15 ps laser, time-dependent optical extinction signals corresponding to nanobubble formation were recorded. The extinction spectra associated with nanobubbles of different diameters were simulated by considering a concentric spherical core-shell model within the Mie theory framework. In the simulations, we assumed an increase in particle temperature. From temporal changes in the experimental data of transient extinctions, we estimated the temporal evolution of the nanobubble diameter. Corrections to bubble-free temperature effects on the transient extinction decays were applied in these experiments by suppressing bubble formation using pressures as high as 60 MPa. The results of this study suggest that the nanobubbles generated around a 60 nm-diameter gold nanoparticle using a fluence of 5.2 mJ cm(-2) had a maximum diameter of 260 ± 40 nm, and a lifetime of approximately 10 ns. The combination of fast transient extinction spectral measurements and spectral simulations provides insights into plasmonic nanobubble dynamics.
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http://dx.doi.org/10.1021/la500663x | DOI Listing |
Infect Drug Resist
December 2024
Centre of Laboratory Medicine, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, Zhejiang, People's Republic of China.
Objective: To compare the performance of a new chemiluminescence method with that of the traditional colloidal gold method for cryptococcal antigen (CrAg) detection.
Methods: Cryptococcosis is a global invasive mycosis associated with significant morbidity and mortality. Cryptococcal antigen (CrAg) testing from serum and cerebrospinal fluid (CSF) has been regarded as the gold standard for early diagnosis.
Colloids Surf B Biointerfaces
December 2024
Institute of Burn Research, Southwest Hospital, State Key Lab of Trauma, Burn and Combined Injury, Army Medical University, Chongqing 400038, China. Electronic address:
Food Chem
December 2024
International Joint Research Laboratory for Biointerface and Biodetection, and School of Food Science and Technology, Jiangnan University, Wuxi, People's Republic of China. Electronic address:
Hen egg-white lysozyme (HEWL) is commonly used in food preservation and as a substitute for sulfur dioxide in wine production and to prevent late blowing defects in cheese production. However, HEWL is an egg allergen that can cause severe allergic reactions in allergic individuals after accidental ingestion. Therefore, in order to prevent life-threatening health problems caused by consumer allergies, we developed an extremely specific gold immunochromatographic assay (GICA) tolerant to matrix effects for the qualification and quantification of HEWL in food products.
View Article and Find Full Text PDFACS Appl Mater Interfaces
December 2024
Department of Chemistry, University of Victoria, PO Box 1700 Stn CSC, Victoria, BC V8W 2Y2, Canada.
Gold nanoparticles (GNPs) encapsulated in amphiphilic block copolymers are a promising system for numerous biomedical applications, although critical information on the effects of various preparation variables on the structure and properties of this unique type of nanomaterial is currently missing from the literature. In this research, we synthesized GNPs functionalized with thiol-terminated polycaprolactone (PCL-GNPs) before encapsulating them into poly(ε-caprolactone)--poly(ethylene glycol) (PCL--PEG) micellar nanoparticles via nanoprecipitation to yield GNP-loaded polymeric nanoparticles (GNP-PNPs). We explored the role of different manufacturing variables (water volume, PCL--PEG to PCL-GNP ratio, and PEG block length) on the sizes, morphologies, GNP occupancies, colloidal gold concentrations, and time stability of GNP-PNPs.
View Article and Find Full Text PDFSci Adv
December 2024
Center for Rare Earth and Inorganic Functional Materials, School of Materials Science and Engineering & National Institute for Advanced Materials, Nankai University, Tianjin 300350, China.
The landmark discovery of gold catalysts has aroused substantial interest in heterogeneous catalysis, yet the catalytic mechanism remains elusive. For carbon monoxide oxidation on gold nanoparticles (NPs) supported on ceria surfaces, it is widely believed that carbon monoxide adsorbs on the gold particles, while the reaction occurs at the gold/ceria interface. Here, we have investigated the dynamic changes of supported gold NPs with various sizes in a carbon monoxide oxidation atmosphere using deep potential molecular dynamics simulations.
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