Ordered two-dimensional arrays such as S-layers 1 , 2 and designed analogues 3 – 5 have intrigued bioengineers, 6 , 7 but with the exception of a single lattice formed with flexible linkers, 8 they are constituted from just one protein component. For modulating assembly dynamics and incorporating more complex functionality, materials composed of two components would have considerable advantages. 9 – 12 Here we describe a computational method to generate co-assembling binary layers by designing rigid interfaces between pairs of dihedral protein building-blocks, and use it to design a p6m lattice. The designed array components are soluble at mM concentrations, but when combined at nM concentrations, rapidly assemble into nearly crystalline micrometer-scale arrays nearly identical (based on TEM and SAXS) to the computational design model in vitro and in cells without the need for a two-dimensional support. Because the material is designed from the ground up, the components can be readily functionalized, and their symmetry reconfigured, enabling formation of ligand arrays with distinguishable surfaces which we demonstrate can drive extensive receptor clustering, downstream protein recruitment, and signaling. Using AFM on supported bilayers and quantitative microscopy on living cells, we show that arrays assembled on membranes have component stoichiometry and structure similar to arrays formed in vitro, and thus that our material can impose order onto fundamentally disordered substrates like cell membranes. In sharp contrast to previously characterized cell surface receptor binding assemblies such as antibodies and nanocages, which are rapidly endocytosed, we find that large arrays assembled at the cell surface suppress endocytosis in a tunable manner, with potential therapeutic relevance for extending receptor engagement and immune evasion. Our work paves the way towards a synthetic cell biology, where a new generation of multi-protein macroscale materials is designed to modulate cell responses and reshape synthetic and living systems.

We present a theoretical and experimental investigation of the recently reported new architecture of a patterned electrode vertical field effect transistor (PE-VFET). The investigation focuses on the role of the embedded source electrode architecture in the device behavior. Current-voltage characteristics was unraveled through the use of a self-consistent numerical simulation resulting in guidelines for the PE-VFET architecture regarding the On/Off current ratio, output current density, and apparent threshold voltage. Current modulation characteristics are obtained through the formation of virtual contacts at the PE nano-features (i.e., perforations) under gate bias, which lead to the formation of vertical channels under drain bias. As the vertical channel is formed the device characteristics change from contact-limited to space-charge-limited. The analytical model strength is shown with the parameter extraction procedure applied to a measured PE-VFET device fabricated using block copolymer lithography and with the appropriate simulation results.

We report the design and implementation of a vertical organic field effect transistor which is compatible with standard device fabrication technology and is well described by a self consistent device model. The active semiconductor is a film of C 60 molecules, and the device operation is based on the architecture of the nanopatterned source electrode. The relatively high resolution fabrication process and maintaining the low-cost and simplicity associated with organic electronics, necessitates unconventional fabrication techniques such as soft lithography. Block copolymer self-assembled nanotemplates enable the production of conductive, gridlike metal electrode. The devices reported here exhibit On/Off ratio of 10 4 .

While organic transistors' performances are continually pushed to achieve lower power consumption, higher working frequencies, and higher current densities, a new type of organic transistors characterized by a vertical architecture offers a radically different design approach to outperform its traditional counterparts. Naturally, the distinct vertical architecture gives way to different governing physical ground rules and structural key features such as the need for an embedded transparent electrode. In this paper, we make use of a zero-frequency electric field-transparent patterned electrode produced through block-copolymer self-assembly based lithography to control the performances of the vertical organic field effect transistor (VOFET) and to study its governing physical mechanisms. Unlike other VOFET structures, this design, involving well-defined electrode architecture, is fully tractable, allowing for detailed modeling, analysis, and optimization. We provide for the first time a complete account of the physics underpinning the VOFET operation, considering two complementary mechanisms: the virtual contact formation (Schottky barrier lowering) and the induced potential barrier (solid-state triode-like shielding). We demonstrate how each mechanism, separately, accounts for the link between controllable nanoscale structural modifications in the patterned electrode and the VOFET performances. For example, the ON/OFF current ratio increases by up to 2 orders of magnitude when the perforations aspect ratio (height/width) decreases from ∼0.2 to ∼0.1. The patterned electrode is demonstrated to be not only penetrable to zero-frequency electric fields but also transparent in the visible spectrum, featuring uniformity, spike-free structure, material diversity, amenability with flexible surfaces, low sheet resistance (20-2000 Ω sq(-1)) and high transparency (60-90%). The excellent layer transparency of the patterned electrode and the VOFET's exceptional electrical performances make them both promising elements for future transparent and/or efficient organic electronics.