Characterization and quantification of two-dimensional silver nanoplates using single particle-inductively coupled...

Two-dimensional silver (Ag) nanomaterials, such as triangular Ag nanoplates (Ag NPLs), exhibit exceptional optical properties and antibacterial activity. However, the anisotropic nature of the nanostructures presents significant challenges for accurately characterizing and quantifying Ag NPLs compared to their isotropic counterparts using routine analytical techniques. This limitation poses a serious obstacle to understanding their environmental and biological behavior. In this study, we systematically evaluated the performance of single-particle inductively coupled plasma-mass spectrometry (spICP-MS) for analyzing Ag NPLs with varying properties for the first time. Our findings indicate that spICP-MS provides superior accuracy and reliability in both qualitative and quantitative analyses of triangular Ag NPLs with edge lengths of 70 nm, 100 nm, 140 nm, 160 nm, and 270 nm when compared to commonly employed light scattering-based techniques such as nanoparticle tracking analysis (NTA) and flow cytometry (FC). The size detection limit of the established spICP-MS method reaches the edge length of 70 nm for Ag NPLs. Compared with spectral techniques, spICP-MS offers the advantage of absolute quantification of Ag nanoparticles even at concentrations as low as 10² particles mL^-1, while remaining independent of particle morphology. This detection capability is 4∼6 orders of magnitude lower than what can be achieved using NTA and FC. This approach is anticipated to enhance the comprehensive understanding of the behavior of two-dimensional Ag nanomaterials within biological and environmental medium.