Graphene liquid cells (GLCs) for transmission electron microscopy (TEM) enable high‐resolution, real‐time imaging of dynamic processes in water. Large‐scale implementation, however, is prevented by... Show moreGraphene liquid cells (GLCs) for transmission electron microscopy (TEM) enable high‐resolution, real‐time imaging of dynamic processes in water. Large‐scale implementation, however, is prevented by major difficulties in reproducing GLC fabrication. Here, a high‐yield method is presented to fabricate GLCs under millimeter areas of continuous graphene, facilitating efficient GLC formation on a TEM grid. Additionally, GLCs are located on the grid using correlated light‐electron microscopy (CLEM), which reduces beam damage by limiting electron exposure time. CLEM allows the acquisition of reliable statistics and the investigation of the most common shapes of GLCs. In particular, a novel type of liquid cell is found, formed from only a single graphene sheet, greatly simplifying the fabrication process. The methods presented in this work—particularly the reproducibility and simplicity of fabrication—will enable future application of GLCs for high‐resolution dynamic imaging of biomolecular systems. Show less
Graphene liquid cells (GLCs) for transmission electron microscopy (TEM) enable high-resolution, real-time imaging of dynamic processes in water. Large-scale implementation, however, is prevented by... Show moreGraphene liquid cells (GLCs) for transmission electron microscopy (TEM) enable high-resolution, real-time imaging of dynamic processes in water. Large-scale implementation, however, is prevented by major difficulties in reproducing GLC fabrication. Here, a high-yield method is presented to fabricate GLCs under millimeter areas of continuous graphene, facilitating efficient GLC formation on a TEM grid. Additionally, GLCs are located on the grid using correlated light-electron microscopy (CLEM), which reduces beam damage by limiting electron exposure time. CLEM allows the acquisition of reliable statistics and the investigation of the most common shapes of GLCs. In particular, a novel type of liquid cell is found, formed from only a single graphene sheet, greatly simplifying the fabrication process. The methods presented in this work-particularly the reproducibility and simplicity of fabrication-will enable future application of GLCs for high-resolution dynamic imaging of biomolecular systems. Show less
Direct electrical probing of molecular materials is often impaired by their insulating nature. Here, graphene is interfaced with single crystals of a molecular spin crossover complex, [Fe(bapbpy)... Show moreDirect electrical probing of molecular materials is often impaired by their insulating nature. Here, graphene is interfaced with single crystals of a molecular spin crossover complex, [Fe(bapbpy)(NCS)2], to electrically detect phase transitions in the molecular crystal through the variation of graphene resistance. Contactless sensing is achieved by separating the crystal from graphene with an insulating polymer spacer. Next to mechanical effects, which influence the conductivity of the graphene sheet but can be minimized by using a thicker spacer, a Dirac point shift in graphene is observed experimentally upon spin crossover. As confirmed by computational modeling, this Dirac point shift is due to the phase‐dependent electrostatic potential generated by the crystal inside the graphene sheet. This effect, named as chemo‐electric gating, suggests that molecular materials may serve as substrates for designing graphene‐based electronic devices. Chemo‐electric gating, thus, opens up new possibilities to electrically probe chemical and physical processes in molecular materials in a contactless fashion, from a large distance, which can enhance their use in technological applications, for example, as sensors. Show less
Two-dimensional (2D) membranes featuring arrays of sub-nanometer pores have applications in purification, solvent separation and water desalination. Compared to channels in bulk membranes, 2D... Show moreTwo-dimensional (2D) membranes featuring arrays of sub-nanometer pores have applications in purification, solvent separation and water desalination. Compared to channels in bulk membranes, 2D nanopores have lower resistance to transmembrane transport, leading to faster passage of ions. However, the formation of nanopores in 2D membranes requires expensive post-treatment using plasma or ion bombardment. Here, we study bottom-up synthesized porous carbon nanomembranes (CNMs) of biphenyl thiol (BPT) precursors. Sub-nanometer pores arise intrinsically during the BPT-CNM synthesis with a density of 2 ± 1 pore per 100 nm2. We employ BPT-CNM based pore arrays as efficient ion sieving channels, and demonstrate selectivity of the membrane towards ion transport when exposed to a range of concentration gradients of KCl, CsCl and MgCl2. The selectivity of the membrane towards K+ over Cl− ions is found be 16.6 mV at a 10 : 1 concentration ratio, which amounts to ∼30% efficiency relative to the Nernst potential for complete ion rejection. The pore arrays in the BPT-CNM show similar transport and selectivity properties to graphene and carbon nanotubes, whilst the fabrication method via self-assembly offers a facile means to control the chemical and physical properties of the membrane, such as surface charge, chemical nature and pore density. CNMs synthesized from self-assembled monolayers open the way towards the rational design of 2D membranes for selective ion sieving. Show less
Two-dimensional (2D) membranes featuring arrays of sub-nanometer pores have applications in purification, solvent separation and water desalination. Compared to channels in bulk membranes, 2D... Show moreTwo-dimensional (2D) membranes featuring arrays of sub-nanometer pores have applications in purification, solvent separation and water desalination. Compared to channels in bulk membranes, 2D nanopores have lower resistance to transmembrane transport, leading to faster passage of ions. However, the formation of nanopores in 2D membranes requires expensive post-treatment using plasma or ion bombardment. Here, we study bottom-up synthesized porous carbon nanomembranes (CNMs) of biphenyl thiol (BPT) precursors. Sub-nanometer pores arise intrinsically during the BPT-CNM synthesis with a density of 2 ± 1 pore per 100 nm2. We employ BPT-CNM based pore arrays as efficient ion sieving channels, and demonstrate selectivity of the membrane towards ion transport when exposed to a range of concentration gradients of KCl, CsCl and MgCl2. The selectivity of the membrane towards K+ over Cl− ions is found be 16.6 mV at a 10 : 1 concentration ratio, which amounts to ∼30% efficiency relative to the Nernst potential for complete ion rejection. The pore arrays in the BPT-CNM show similar transport and selectivity properties to graphene and carbon nanotubes, whilst the fabrication method via self-assembly offers a facile means to control the chemical and physical properties of the membrane, such as surface charge, chemical nature and pore density. CNMs synthesized from self-assembled monolayers open the way towards the rational design of 2D membranes for selective ion sieving. Show less
In the treatment of cancer, targeting of anticancer drugs to the tumor microenvironment is highly desirable. Not only does this imply accurate tumor targeting but also minimal drug release en route... Show moreIn the treatment of cancer, targeting of anticancer drugs to the tumor microenvironment is highly desirable. Not only does this imply accurate tumor targeting but also minimal drug release en route to the tumor and maximal drug release once there. Here we describe high-loading, “stealth-like” doxorubicin micelles as a pro-drug delivery system, which upon light activation, leads to burst-like doxorbicin release. Through this approach, we show precise spatiotemporal control of doxorubicin delivery to cells in vitro. Show less
