Water Dispersive Suprastructures: An Organizational Impact on Nanomechanical Properties

Abstract

Water dispersive 2D and 3D suprastructures offer a large number of potential applications in energy release, biomedicine and other fields. The nanomechanical properties of two suprastructures of self‐assembled 9.6 nm Fe3O4 hydrophobic nanocrystals dispersed in water are elucidated by using atomic force microscopy. These suprastructures are either a shell consisting of a few layers of nanocrystals or spherical self‐assemblies of nanocrystals in fcc superlattices called colloidosomes and supraballs, respectively. The major difference in the preparation of these suprastructure is based on the presence or not of octadecene molecules. It is recently demonstrated that these structures behave as nanoheaters and remain self‐assembled after internalization in cancer cells. The observed differences between these suprastructures in terms of cell sensing are suggested to be related to their mechanical properties, which emphasize the importance of better understanding the nanomechanics of such suprastructures. In this study the nanomechanical properties of these suprastructures are shown to be load‐depended in aqueous medium. Colloidosomes demonstrate higher flexibility and deformability than the supraballs. These findings provide essential knowledge for understanding differences in cell internalization and implementation in biomedicine. The differences in nanomechanical properties between these types of suprastructures are mainly due to their structures (hollow core–shell or fcc supracrystals).

Chemically-Controlled Ultrafast Photothermal Response in Plasmonic Nanostructured Assemblies

“… 44 Here with nanoegg suprastructures, we combine the flexibility of colloidosomes and the comparative rigidity of supraballs. 59 Furthermore, here we observed an increase in the global temperature, different from the results obtained with colloidosomes and supraballs. From these data we can reasonably assume a very high efficiency in the photothermal effect induced by water-soluble NC assemblies, which therefore exhibit high performances as nanoheaters and could be used in several research areas and as therapeutic agents.…”

Self-Assemblies of Nanocrystals in Tumor Cells: Controlling the Intracellular Fate, Manipulation, and Photothermal Effects

“…Note that some colloidosomes are also composed of a few nanocrystal layers (Figure b). This is confirmed by the AFM 3D tomography image where step edge structure are observed (Figure f) . This highlights the layered structure in the suprastructure.…”

“…This is confirmed by the AFM 3D tomography image where step edge structure are observed (Figure 1f). 14 This highlights the layered structure in the suprastructure. Furthermore, the height of the steps (10 nm) is consistent with that of the nanocrystal sizes associated with organic coating (Figure 1g).…”

“…Colloidosome, deposited on a modified silica surface, is imaged in water. 14 From AFM in quantitative imaging, the topography is evaluated from the position of the piezoelectric actuator at the given imaging force. For a load equal (or less) than 1.5 nN, colloidosome is spherical, and its reversible deformation increases with increasing load and reaches half height.…”

“…The corner stone of nanomedicine remains the tight control of nanomaterial interactions with the encountered biological environments . Considering the process of cellular internalization of nanomaterials, a considerable effort is made to understand the effects of size, shape, material, charge, surface chemistry, chemical composition, flexibility, stiffness properties of nanocarriers, and the interplay among these on the mechanisms of cellular uptake by immune cells or tumor cells. − …”