Liquid-cell scanning transmission electron microscopy and fluorescence correlation spectroscopy of DNA-directed gold nanoparticle assemblies

Enhancing and Mitigating Radiolytic Damage to Soft Matter in Aqueous Phase Liquid-Cell Transmission Electron Microscopy in the Presence of Gold Nanoparticle Sensitizers or Isopropanol Scavengers

“…Despite the ubiquity of GNPs in LCTEM literature, both by themselves as preformed nanocrystals − ,, and in the presence of soft materials, ,− the sensitizing effect of GNPs has not been directly experimentally explored in the context of LCTEM. Furthermore, though scavengers have been used previously in LCTEM, − there is a lack of fundamental studies dealing with scavengers as aids for imaging soft matter.…”

Investigating electron beam interactions with nanoparticle capping ligands using correlative liquid phase transmission electron microscopy and fluorescence microscopy

“…Thilini Dissanayake 1 , Mei Wang 2 and Taylor Woehl 2 1 University of Maryland, College Park, Maryland, United States, 2 University of Maryland, United States Liquid phase transmission electron microscopy (LPTEM) has been widely used for real time imaging of nanoscale dynamics in nanoparticles (NPs) systems in liquid phase where nanoparticles are functionalized with different types of ligands ranging from small molecules to polymers [1,2,3]. Capping ligands control colloidal interparticle interactions that are important in directing assembly between NPs; however, interactions between the electron beam and capping ligands during LPTEM have not been studied.…”

Revealing Reactions between the Electron Beam and Nanoparticle Capping Ligands with Correlative Fluorescence and Liquid-Phase Electron Microscopy

“…Liquid-phase transmission electron microscopy (LP-TEM) can uniquely visualize the dynamics of nanoparticle self-assembly in a liquid medium in real-time with nanometer scale resolution. Numerous LP-TEM studies have investigated the self-assembly of nanoparticles functionalized with small molecules, polymers, and DNA capping ligands. − Interparticle interactions during self-assembly, including steric forces, electrostatic forces, hydrogen bonding, and hydrophobic/hydrophilic forces, are mediated by the specific physicochemical properties ( e.g ., molecular weight, ligand density, functional groups, protonation/deprotonation) of organic surface ligands on nanoparticles. , It is well known that the TEM beam strongly interacts with organic molecules through radiolysis reactions. , However, despite the importance of organic capping ligands in self-assembly and their susceptibility to electron beam damage, few LP-TEM studies have focused on electron beam damage mechanisms of organic capping ligands. To correctly interpret self-assembly dynamics and mechanisms observed with LP-TEM, it is imperative to understand how the electron beam modifies nanoparticle surface ligands and to establish limits on the electron doses and dose rates used to image nanoparticle self-assembly.…”