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Abstract: The direct imaging of individual atoms within the cellular context holds great potential for understanding the fundamental physical and chemical processes in organisms. Here, a novel approach for imaging of electrically insulated biological cells by introducing a graphene encapsulation approach to “disguise” the low‐conductivity barrier is reported. Upon successful coating using a water‐membrane‐based protocol, the electrical properties of the graphene enable voltage pulsing field evaporation for atom probe tomography (APT). Low conductive specimens prepared from both Au nanoparticles and antibiotic‐resistant bacterial cells have been tested. For the first time, a significant graphene‐enhanced APT mass resolving power is also observed confirming the improved compositional accuracy of the 3D data. The introduction of 2D materials encapsulation lays the foundation for a breakthrough direction in specimen preparation from nanomembrane and nanoscale biological architectures for subsequent 3D near‐atomic characterization. [ABSTRACT FROM AUTHOR]

Free‐standing 2D nanoassemblies are ultrathin nanomembranes or nanosheets constructed from constituent nanoscale building blocks including metal nanoparticles, quantum dots, and magnetic nanoparticles, typically by a bottom‐up self‐assembly approach. Such free‐standing nanoassemblies are a new class of advanced functional materials that can integrate the unique optoelectronic properties of nanomaterials with thin film mechanics into confined 2D space. This offers attributes such as minimizing substrate effects, facile transfer, and soft devices in comparison to the corresponding substrate‐supported system. This review covers the recent progress in fabrication, characterization, and application of the free‐standing 2D nanoassemblies. To begin with, the attributes of free‐standing 2D nanoassemblies are discussed, followed by the description of fabrication methodologies. Then their novel optical, electronic, mechanical, magnetic, and stimuli responsible properties are covered, and their potential applications in filtration membrane, nanomechanical devices, and chemical sensing are further discussed. Finally, perspectives on the challenges and future opportunities of the free‐standing 2D nanoassemblies are shared. [ABSTRACT FROM AUTHOR]