An official website of the United States government
Abstract DNA tiles serve as the fundamental building blocks for DNA self-assembled nanostructures such as DNA arrays, origami, and designer crystals. Introducing additional binding arms to DNA crossover tiles holds the promise of unlocking diverse nano-assemblies and potential applications. Here, we present one-, two-, and three-layer T-shaped crossover tiles, by integrating T junction with antiparallel crossover tiles. These tiles carry over the orthogonal binding directions from T junction and retain the rigidity from antiparallel crossover tiles, enabling the assembly of various 2D tessellations. To demonstrate the versatility of the design rules, we create 2-state reconfigurable nanorings from both single-stranded tiles and single-unit assemblies. Moreover, four sets of 4-state reconfiguration systems are constructed, showing effective transformations between ladders and/or rings with pore sizes spanning ~20 nm to ~168 nm. These DNA tiles enrich the design tools in nucleic acid nanotechnology, offering exciting opportunities for the creation of artificial dynamic DNA nanopores.
more »
« less
Designed 2D protein crystals as dynamic molecular gatekeepers for a solid-state device
Abstract The sensitivity and responsiveness of living cells to environmental changes are enabled by dynamic protein structures, inspiring efforts to construct artificial supramolecular protein assemblies. However, despite their sophisticated structures, designed protein assemblies have yet to be incorporated into macroscale devices for real-life applications. We report a 2D crystalline protein assembly ofC98/E57/E66L-rhamnulose-1-phosphate aldolase (CEERhuA) that selectively blocks or passes molecular species when exposed to a chemical trigger.CEERhuA crystals are engineered via cobalt(II) coordination bonds to undergo a coherent conformational change from a closed state (pore dimensions <1 nm) to an ajar state (pore dimensions ~4 nm) when exposed to an HCN(g) trigger. When layered onto a mesoporous silicon (pSi) photonic crystal optical sensor configured to detect HCN(g), the 2DCEERhuA crystal layer effectively blocks interferents that would otherwise result in a false positive signal. The 2DCEERhuA crystal layer opens in selective response to low-ppm levels of HCN(g), allowing analyte penetration into the pSi sensor layer for detection. These findings illustrate that designed protein assemblies can function as dynamic components of solid-state devices in non-aqueous environments.
more »
« less
- Award ID(s):
- 2011924
- PAR ID:
- 10589202
- Publisher / Repository:
- NPJ
- Date Published:
- Journal Name:
- Nature Communications
- Volume:
- 15
- Issue:
- 1
- ISSN:
- 2041-1723
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract The synthesis of a fluorescent covalent organic framework (COF) using perylene and pyrene building blocks (PEPy‐COF), via a one‐pot condensation reaction is reported. PEPy‐COF is crystallized into 2D nanosheets with a cubic and prismatic crystalline morphology and demonstrates structural stability at temperatures up to 500 °C. The structural morphology is confirmed using X‐ray diffraction and atomic‐level simulations. These 2D porous polymer sheets form a tetragonal framework that is found to have a high specific surface area of 772 m2g−1. Based on the definition of porous materials, the network is mesoporous with an observed pore size of 3.03 nm, which is in good agreement with the material's calculated pore size. The experimentally obtained HOMO‐LUMO band gap is 2.62 eV, confirming the semiconducting nature of PEPy‐COF. PEPy‐COF emits a shiny blue luminescence under UV and visible light. This luminescence intensity is temperature‐dependent in solvents with different polarities and dielectric constants demonstrating that the PEPy‐COF has potential use in a wide range of temperature‐sensing devices. The fluorescence intensity ratio is similar for different temperatures under ultra‐sound conditions and varying solvents.more » « less
-
Abstract In this study, montmorillonite (MMT) nanosheets are purified and exfoliated from a crude clay source and further twice‐functionalized with cetritrimethylammonium bromide and [3‐(2‐aminoethylamino)propyl]trimethoxysliane (AEAPTMS) to promote dispersion in the preceramic polymer. Phase profiles and compositions of MMT nanoflakes and MMT‐silicon oxycarbide (SiOC) are characterized with X‐ray diffraction, infrared spectroscopy, and thermogravimetric analysis. The microstructures are examined by scanning and transmission electron microscopy. MMT nanoflakes are randomly dispersed in the SiOC matrix with α‐quartz forming at the MMT‐SiOC interface. Pyrolysis to 1400 °C induced the formation of SiC nanowhiskers that are observed up to 20 µm in length and 200 nm in diameter. After selective etching of SiO2domains with HF, pore sizes and specific surface areas of MMT‐SiOC are analyzed with nitrogen adsorption. The study provided a new fundamental understanding of MMT‐SiOC interactions at different pyrolysis temperatures and also led to composites with specific surface areas reaching 120 m2 g−1 up to 1200 °C pyrolysis, and between 340 and 772 m2 g−1at 1400 °C pyrolysis and pore size distributions between 2 and 5 nm. The methodology and results presented improve the understanding and viability of 2D nanomaterial‐reinforced ceramic composites and MMT as a precursor for nanostructured SiC.more » « less
-
Abstract A synaptic memristor using 2D ferroelectric junctions is a promising candidate for future neuromorphic computing with ultra‐low power consumption, parallel computing, and adaptive scalable computing technologies. However, its utilization is restricted due to the limited operational voltage memory window and low on/off current (ION/OFF) ratio of the memristor devices. Here, it is demonstrated that synaptic operations of 2D In2Se3ferroelectric junctions in a planar memristor architecture can reach a voltage memory window as high as 16 V (±8 V) and ION/OFFratio of 108, significantly higher than the current literature values. The power consumption is 10−5 W at the on state, demonstrating low power usage while maintaining a large ION/OFFratio of 108compared to other ferroelectric devices. Moreover, the developed ferroelectric junction mimicked synaptic plasticity through pulses in the pre‐synapse. The nonlinearity factors are obtained 1.25 for LTP, −0.25 for LTD, respectively. The single‐layer perceptron (SLP) and convolutional neural network (CNN) on‐chip training results in an accuracy of up to 90%, compared to the 91% in an ideal synapse device. Furthermore, the incorporation of a 3 nm thick SiO2interface between the α‐In2Se3and the Au electrode resulted in ultrahigh performance among other 2D ferroelectric junction devices to date.more » « less
-
The growth of layered 2D compounds is a key ingredient in finding new phenomena in quantum materials, optoelectronics, and energy conversion. Here, we report SnP2Se6, a van der Waals chiral (R3 space group) semiconductor with an indirect bandgap of 1.36 to 1.41 electron volts. Exfoliated SnP2Se6flakes are integrated into high-performance field-effect transistors with electron mobilities >100 cm2/Vs and on/off ratios >106at room temperature. Upon excitation at a wavelength of 515.6 nanometer, SnP2Se6phototransistors show high gain (>4 × 104) at low intensity (≈10−6W/cm2) and fast photoresponse (< 5 microsecond) with concurrent gain of ≈52.9 at high intensity (≈56.6 mW/cm2) at a gate voltage of 60 V across 300-nm-thick SiO2dielectric layer. The combination of high carrier mobility and the non-centrosymmetric crystal structure results in a strong intrinsic bulk photovoltaic effect; under local excitation at normal incidence at 532 nm, short circuit currents exceed 8 mA/cm2at 20.6 W/cm2.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript
- Journal Article:
- https://doi.org/10.1038/s41467-024-50567-8
