Gold and silver nanoparticles with their tunable optical and electronic properties are of great interest for a wide range of applications. Often the ligands at the surface of the nanoparticles have to be exchanged in a second step after particle formation in order to obtain a desired surface functionalization. For many techniques, this process is not accessible in situ. In this review, we present second-harmonic scattering (SHS) as an inherently surface sensitive and label-free optical technique to probe the ligand exchange at the surface of colloidal gold and silver nanoparticles in situ and in real time. First, a brief introduction to SHS and basic features of the SHS of nanoparticles are given. After that, we demonstrate how the SHS intensity decrease can be correlated to the thiol coverage which allows for the determination of the Gibbs free energy of adsorption and the surface coverage.
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http://dx.doi.org/10.1088/1361-648X/aa5a3c | DOI Listing |
PLoS One
January 2025
Faculty of Science and Engineering, Waseda University, Tokyo, Japan.
Gold (or electrum) in hydrothermal fluid precipitates directly from gold sulfide complex and/or partly via suspended nanoparticles. The hydrothermal fluid contains "invisible gold" that is atomically dispersed in sulfide minerals or as nanoparticles with a size of less than 10 nm. However, the contribution of these gold nanoparticles to the formation of native gold and its alloy with silver (electrum) remains unclear.
View Article and Find Full Text PDFDiscov Nano
January 2025
Oral Health Institute, Hamad Medical Corporation, Doha, Qatar.
Phytonanoparticles have emerged as a promising class of biomaterials for enhancing bone regeneration and osseointegration, offering unique advantages in biocompatibility, multifunctionality, and sustainability. This comprehensive review explores the synthesis, characterization, and applications of phytonanoparticles in bone tissue engineering. The green synthesis approach, utilizing plant extracts as reducing and stabilizing agents, yields nanoparticles with intrinsic bioactive properties that can synergistically promote osteogenesis.
View Article and Find Full Text PDFJ Hazard Mater
January 2025
Department of Mechanical, Robotics and Energy Engineering, Dongguk University, Seoul 04620, Republic of Korea. Electronic address:
This paper introduces a highly absorbent and sensitive cellulose nanofiber (CNF)/gold nanorod (GNR)@Ag surface-enhanced Raman scattering (SERS) sensor, fabricated using the vacuum filtration method. By optimizing the Ag thickness in the GNR@Ag core-shell structures and integrating them with CNFs, optimal SERS hotspots were identified using the Raman probe molecule 4-aminothiophenol (4-ATP). To concentrate pesticides extracted from fruit and vegetable surfaces, we utilized the evaporation enrichment effect using hydrophilic CNF and hole-punched hydrophobic polydimethylsiloxane (PDMS).
View Article and Find Full Text PDFBiomed Opt Express
January 2025
Key Laboratory of Optical Technology and Instrument for Medicine, Ministry of Education, University of Shanghai for Science and Technology, 200093 Shanghai, China.
Lung cancer with heterogeneity has a high mortality rate due to its late-stage detection and chemotherapy resistance. Liquid biopsy that discriminates tumor-related biomarkers in body fluids has emerged as an attractive technique for early-stage and accurate diagnosis. Exosomes, carrying membrane and cytosolic information from original tumor cells, impart themselves endogeneity and heterogeneity, which offer extensive and unique advantages in the field of liquid biopsy for cancer differential diagnosis.
View Article and Find Full Text PDFMikrochim Acta
January 2025
College of Chemistry and Chemical Engineering, Xinjiang Normal University, Urumqi, 830054, China.
A AuNSs@PB@Ag-Apt surface-enhanced Raman scattering (SERS) probe has been developed by embedding Prussian blue (PB) between Au core and Ag shell. The PB SERS probe illustrates strong SERS activity in the Raman silent region of 2070 cm, and has a zero background signal, ensuring high sensitivity for the detection of Staphylococcus aureus (S. aureus).
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