Template For Growth Research Articles

Genetically Encoded DNA Origami for Gene Therapy In Vivo.

DNA origami has played an important role in various biomedical applications, including biosensing, bioimaging, and drug delivery. However, the function of the long DNA scaffold involved in DNA origami has yet to be fully exploited. Herein, we report a general strategy for the construction of a genetically encoded DNA origami by employing two complementary DNA strands of a functional gene as the DNA scaffold for gene therapy. In our design, the complementary sense and antisense strands can be directly folded into two DNA origami monomers by their corresponding staple strands. After hybridization, the assembled genetically encoded DNA origami with precisely organized lipids on the surface can function as the template for lipid growth. The lipid-coated and genetically encoded DNA origami can efficiently penetrate the cell membrane for successful gene expression. After decoration with the tumor-targeting group, the antitumor gene (p53) encoded DNA origami can elicit a pronounced upregulation of the p53 protein in tumor cells to achieve efficient tumor therapy. The targeting group-modified, lipid-coated, and genetically encoded DNA origami has mimicked the functions of cell surface ligands, cell membrane, and nucleus for communication, protection, and gene expression, respectively. This rationally developed combination of folding and coating strategies for genetically encoded DNA origami presents a new avenue for the development of gene therapy.

Nanopatterned rGO/ZnO:Al seed layer for vertical growth of single ZnO nanorods

In this work, we demonstrate a novel low-cost template-assisted route to synthesize vertical ZnO nanorod arrays on Si (100). The nanorods were grown on a patterned double seed layer comprised of reduced graphene oxide (rGO) and Al-doped ZnO nanoparticles. The seed layer was fabricated by spray-coating the substrate with graphene and then dip-coating it into a Al-doped ZnO sol–gel solution. The growth template was fabricated from a double-layer resist, spin-coated on top of the rGO/ZnO:Al seed layer, and patterned by colloidal lithography. The results show a successful chemical bath deposition of vertically aligned ZnO nanorods with controllable diameter and density in the nanoholes in the patterned resist mask. Our novel method can presumably be used to fabricate electronic devices on virtually any smooth substrate with a thermal budget of 1 min at 300 °C with the seed layer acting as a conductive strain-relieving back contact. The top contact can simply be made by depositing a suitable transparent conductive oxide or metal, depending on the specific application.

III–V selective regrowth on SOI for telecom lasers in silicon photonics

To realize fully integrated silicon photonics (Si photonics), reliable III–V light sources that can be efficiently coupled with Si/SiN waveguides are essential. Here, based on a monolithic InP/silicon-on-insulator (SOI) platform, we developed a selective regrowth scheme and constructed a regrowth platform for on-chip lasers that can be efficiently coupled with Si/SiN waveguides. InP and InGaAs/InP multi-quantum wells (MQWs) were regrown on the regrowth template on SOI as well as patterned commercial InP wafers in the same growth run for comparison. A flat (001) top surface after regrowth with a low roughness of 0.38 nm was obtained on SOI. Benefitting from the high quality of MQWs regrowth, strong photoluminescence emission at telecom band can be obtained on both growth templates. Also, multi-wavelength emission on the same chip can be potentially achieved by designing various regrowth openings. Furthermore, the large material volume with vertical stacking structure and intimate placement of MQWs and the Si layer of SOI allow for the potential demonstration of electrically pumped lasers and efficient light coupling between them and Si/SiN waveguides. Therefore, the demonstrated regrowth method provides a promising solution for the monolithic integration of III–V on-chip lasers on Si.

Disordered Phase-Assisted Growth of Organic Semiconductor Crystals on Self-Assembled Monolayer Templates.

Achieving high mobility and bias stability is a challenging obstacle in the advancement of organic thin-film transistors (OTFTs). To this end, the fabrication of high-quality organic semiconductor (OSC) thin films is critical for OTFTs. Self-assembled monolayers (SAMs) have been used as growth templates for high-crystalline OSC thin films. Despite significant research progress in the growth of OSC on SAMs, a detailed understanding of the growth mechanism of the OSC thin films on a SAM template is lacking, which has limited its use. In this study, the effects of the structure (thickness and molecular packing) of SAM on the nucleation and growth behavior of the OSC thin films were investigated. We found that disordered SAM molecules assisted in the surface diffusion of the OSC molecules and resulted in a small nucleation density and large grain size of the OSC thin films. Moreover, a thick SAM with disordered SAM molecules on the top was found to be beneficial for the high mobility and bias stability of the OTFTs.

Cirrhotic Liver Sustains In Situ Regeneration of Acellular Liver Scaffolds after Transplantation into G-CSF-Treated Animals.

Acellular liver scaffolds (ALS) produced by decellularization have been successfully explored for distinct regenerative purposes. To date, it is unknown whether transplanted ALSs are affected by cirrhotic livers, either becoming cirrhotic themselves or instead remaining as a robust template for healthy cell growth after transplantation into cirrhotic rats. Moreover, little is known about the clinical course of recipient cirrhotic livers after ALS transplantation. To address these questions, we transplanted ALSs into cirrhotic rats previously treated with the granulocyte colony-stimulating factor. Here, we report successful cellular engraftment within the transplanted ALSs at 7, 15, and 30 days after transplantation. Recellularization was orchestrated by liver tissue cell activation, resident hepatocytes and bile duct proliferation, and an immune response mediated by the granulocyte components. Furthermore, we showed that transplanted ALSs ensured a pro-regenerative and anti-inflammatory microenvironment, attracted vessels from the host cirrhotic tissue, and promoted progenitor cell recruitment. ALS transplantation induced cirrhotic liver regeneration and extracellular matrix remodeling. Moreover, the transplanted ALS sustained blood circulation and attenuated alterations in the ultrasonographic and biochemical parameters in cirrhotic rats. Taken together, our results confirm that transplanted ALSs are not affected by cirrhotic livers and remain a robust template for healthy cell growth and stimulated cirrhotic liver regeneration.

Nanorod array-induced growth of high-quality Sb2Se3 absorber layers for efficient planar solar cells

Antimony selenide (Sb2Se3) has been applied extensively in the field of optoelectronics because of its excellent material and photoelectric properties, as well as its potential low cost effectiveness. Owing to its unique quasi-one-dimensional structure, the preparation of an Sb2Se3 absorption layer with high crystallization quality and standing preferred orientation is crucial for constructing high-performance Sb2Se3 devices. Herein, we reported a new method for the subsequent epitaxial growths of Sb2Se3 thin films with high crystallization and preferred standing orientations using the Sb2Se3 nanorod array as growth template on the Mo substrate and summarized the growth mechanism of the nanorod arrays. High crystal quality and crystal orientation can be easily controlled, carrier recombination is reduced, charge transport is enhanced, and the performance of Sb2Se3 device is improved significantly. As high as 6.3 % power-to-efficiency with a fill factor of 62 % has been achieved for the champion device. This general-purpose nanorod array template growth film provides an effective reference for the growth control of other low latitude crystal films.

Flexible self-powered DUV photodetectors with high responsivity utilizing Ga2O3/NiO heterostructure on buffered Hastelloy substrates

In this research, β-Ga2O3/NiO heterostructures were grown directly on CeO2 buffered Hastelloy flexible substrates. With pulsed laser deposition under high temperatures, as-grown β-Ga2O3 and NiO thin films have a preferred out-of-plane orientation along the ⟨−201⟩ and ➎111➉ directions. This is due to the ideal epitaxial ability of the CeO2 buffer layer, which serves as a perfect template for the epitaxial growth of single-oriented NiO and β-Ga2O3 by creating a constant gradient from CeO2 (2.7 Å along ➎001➉) to NiO (2.9 Å along ➎110➉), and eventually to β-Ga2O3 (3.04 Å along ➎010➉). The Hastelloy substrates endow photodetectors with good deformability and mechanical robustness. Moreover, owing to the type-II band alignment of β-Ga2O3/NiO heterostructures, the photodetectors have a good photocurrent at zero bias under 284 nm of light illumination. In addition, the photocurrent is significantly higher than when using an analogous heterostructure (as described in some previous reports), because the β-Ga2O3 and NiO thin films are crystalized along a single orientation with fewer defects.

Synergistic Fluorine⋅⋅⋅Sulfur Intra‐ and Intermolecular Interactions on Dopant‐Free Hole Transport Material for Efficient and Stable Inverted Perovskite Solar Cells

Designing dopant‐free small‐molecule hole transport materials (HTMs) with self‐assembly behavior via noncovalent interactions is considered as one effective strategy to achieve high‐performance inverted perovskite solar cells (PSCs). Herein, two donor‐π bridge‐donor (D–π–D) HTMs are presented, TPASF and TPAOF, containing 3,6‐dimethoxythieno[3,2‐b]thiophene as a core part with 3‐fluoro‐N,N‐bis(4‐(methylthio)phenyl)aniline and 3‐fluoro‐N,N‐bis(4‐methoxyphenyl)aniline as side group. The synergistic F⋅⋅⋅S dipole–dipole intra‐ and intermolecular interactions in TPASF drive the self‐assembly of this molecule into a supramolecular nanofibrillar network, leading to high hole mobility, superior interfacial properties, and providing a good growth template for the perovskite layer atop. The corresponding dopant‐free TPASF‐based inverted devices exhibit a promising power conversion efficiency of 21.01% with a long T 80 lifetime of ≈632 h under operational conditions. This work paves the way for the further development of new dopant‐free self‐assembled HTM designs for highly efficient and stable inverted PSCs.

Microstructure and evolution of hafnium carbide whiskers via polymer-derived ceramics: A novel formation mechanism

Polymer-derived ultra-high-temperature ceramic (UHTC) nanocomposites have attracted growing attention due to the increasing demands for advanced thermal structure components in aerospace. Herein, hafnium carbide (HfC) whiskers are successfully fabricated in carbon fiber preforms via the polymer-derived ceramic (PDC) method. A novel carbon nanotube (CNT) template growth mechanism combined with the PDC method is proposed in this work, which is different from the conventional vapor–liquid–solid (VLS) mechanism that is commonly used for polymer-derived nanostructured ceramics. The CNTs are synthesized and proved to be the templates for fabricating the HfC whiskers, which are generated by the released low-molecular-weight gas such as CO, CO₂, and CH₄ during the pyrolysis of a Hf-containing precursor. The formed products are composed of inner single crystal HfC whiskers that are measured to be several tens of micrometers in length and 100–200 nm in diameter and outer HfC/HfO₂ particles. Our work not only proposes a new strategy to prepare the HfC whiskers, but also puts forward a new thinking of the efficient utilization of a UHTC polymer precursor.

Templated Synthesis of Diamond Nanopillar Arrays Using Porous Anodic Aluminium Oxide (AAO) Membranes

Diamond nanostructures are mostly produced from bulk diamond (single- or polycrystalline) by using time-consuming and/or costly subtractive manufacturing methods. In this study, we report the bottom-up synthesis of ordered diamond nanopillar arrays by using porous anodic aluminium oxide (AAO). Commercial ultrathin AAO membranes were adopted as the growth template in a straightforward, three-step fabrication process involving chemical vapor deposition (CVD) and the transfer and removal of the alumina foils. Two types of AAO membranes with distinct nominal pore size were employed and transferred onto the nucleation side of CVD diamond sheets. Subsequently, diamond nanopillars were grown directly on these sheets. After removal of the AAO template by chemical etching, ordered arrays of submicron and nanoscale diamond pillars with ~325 nm and ~85 nm diameters were successfully released.

Efficient activation of peroxymonosulfate by MoS2 intercalated MgCuFe layered double hydroxide for phenol pollutant control

The application of MoS2 as an emerging cocatalyst in wastewater treatment is of great significance, but the efficiency of cocatalyst is often limited due to its easy agglomeration and insufficient interaction with the catalyst. Here, we used layered double hydroxide (LDH) as the catalyst and the growth template of MoS2 to achieve an efficient combination of catalyst and cocatalyst in the removal of organic pollutants by peroxymonosulfate (PMS) activation. The outcomes showed that the MoS2 intercalated LDH composite samples (MLDH) owned excellent phenol degradation performance, reaching nearly 100% removal within 10 min, and the calculated apparent rate constants were 2.3, 5.6, 17.7 and 19.8 times higher than that of the samples of directly growing MoS2 on the LDH (M@LDH), physically blended MoS2 and LDH samples, LDH and MoS2, respectively. Based on the results of electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS), SO4•- had a major impact on the elimination of phenol, Mo(Ⅳ) in MoS2 also participated in and encouraged the Fe(Ⅲ)/Fe(Ⅱ) redox cycle, providing the driving force for the further activation of PMS. Moreover, the effects of pH value, anions, cations and water environment of MLDH during the activation of PMS were also determined, and it was found that under various catalytic environments, MLDH always maintained a high removal rate of phenol and showed strong anti-interference ability. Collectively, the results of this research would offer more possibilities and suggestions for creating highly effective catalysts for wastewater cleanup.

Evaluation of chemical structure and Si segregation of Al/Si(111)

Control of diffusion and segregation of Si atoms through a thin metal layer from a stacked Si structure is one of the effective techniques to grow two-dimensional (2D) or ultrathin Si crystals. We have studied the formation of the Al layer with a flat surface and high crystallinity on a wet-cleaned Si(111) wafer by thermal evaporation in order to use it as a growth template for ultrathin Si crystals. Then, the impacts of the annealing in N2 ambient on the surface flatness, the Al crystallinity, and the chemical bonding features for the Al/Si(111) structure were investigated. A formation of a sub-nanometer Si layer on the Al(111) surface using Si segregation with keeping surface flatness was demonstrated by the control of annealing temperature.

One-step growth of the interconnected carbon nanotubes/graphene hybrids from cuttlebone-derived bi-functional catalyst for lithium-ion batteries

Carbon nanotubes/graphene hybrid materials with excellent physicochemical properties can be widely applied in the fields of energy storage, electrocatalysis, sensing, etc. Reducing the self-stacking and achieving covalent interaction between carbon nanotubes and graphene are important to ensure a stable hierarchical architecture and effective mass transfer. Herein, we propose a one-step strategy to synthesize 3D interconnected carbon nanotubes/graphene hybrids on the easy-to-remove biomass-derived substrate. The calcined natural cuttlebone as bi-functional catalyst precursor can simultaneously grow carbon nanotubes and graphene by one-step chemical vapor deposition without the addition of extra metal catalysts, while the interconnected structure can act as the porous template for graphene growth. The simultaneous growth process can obtain covalent bonding between carbon nanotubes and graphene, while the crystalline quality and interlayer space can be adjusted by different carbon sources and growth parameters (e.g., temperature). The one-step grown carbon nanotubes/graphene hybrids with seamless interfaces and hierarchical interconnected 3D structure can effectively enhance the electron transfer as well as the electrolyte infiltration efficiency. When utilized as lithium-ion batteries (LIBs) anode, a high specific capacity (544 mAh g–1 at 0.1 A g–1), good rate capability (200 mAh g–1 at 6.4 A g–1 with an ultrashort charge time of 113 s), and excellent cyclic stability can be achieved. This simple and one-step carbon nanotubes/graphene hybrids fabrication strategy can be easily scale-up and applied in various fields.

The effect of passivation to etching duration ratio on bipolar electrochemical etching of porous layer stacks in germanium

The effect of the passivation to etching duration ratio on the bipolar electrochemical etching of highly p-doped germanium on its pore structures has been investigated. The final goal is the development of porous multi-layer stacks consisting of a closed growth template and separation layer for lift-off. In particular, changing the passivation duration allows different types of porous structures to be obtained. These range from a strong crystallographic orientation dependent dissolution to multi-layer structures consisting of “sponge” and “pine-tree” shapes. In this work, the degree of passivation was considered first and foremost since it is one way of controlling the formation of molecular hydrogen and surface atom protection. In addition, certain areas of the porous structure can be protected and, assuming a different space charge region width, selective etching is possible. Finally, by combining various successive processes, a porous multi-layer structure can be etched, including separation layers. In this work the most dominant reoccurring structures have been described using a model that contains the aforementioned assumptions.

Superconducting FeSe membrane synthesized by etching of water-soluble Sr3Al2O6 layer

The development of the epitaxial lift-off technique using a pseudoperovskite Sr3Al2O6 sacrificial layer has unleashed latent physical properties emerging in freestanding membranes, mainly composed of lattice-matched perovskite-type complex oxides. Here, we report the superconductivity in a freestanding single-crystalline FeSe membrane prepared using a SrTiO3 capped water-soluble Sr3Al2O6 sacrificial layer, which serves as an ex situ growth template. The FeSe membrane is synthesized by etching the sacrificial layer and transferred on a SiO2/Si substrate. X-ray diffraction pattern and scanning transmission electron microscopy reveal that the FeSe membrane is fully relaxed with minimum degradation of its structural properties during the lift-off process. A superconductivity with zero resistance below 4.2 K is exhibited in the freestanding FeSe membrane, while it is not observed in a compressed thin-film form by an in-plane tensile strain. In addition, critical magnetic field and critical current density of the FeSe membrane are comparable to those of the bulk single crystal. Our demonstration of the superconducting FeSe membrane ensures a high utility of the epitaxial lift-off technique for various thin-film materials grown on SrTiO3. This study paves the way for functional applications using ex situ thin-film growth and lift-off technique with an expanded selection from an inventory of various materials.

Ni3S4/SnS/Graphene Oxide/Carbon Nanotube Composites as Anodes for Na-Ion Batteries

To boost the electrochemical kinetics of sodium-ion batteries (SIBs), scheming of nanocomposite materials and apprehending the synergistic effect between synthesized constituents are rationally vital. Due to high performance and superior theoretical capacity, transition-metal sulfides appear prominent anode applicants for SIBs. Still, constraints exist in their practical usage due to structural damage, leading to poor cycling stability, severe capacity loss, and low rate performance. In this study, an integrated amalgam of Ni3S4/SnS (NTS) heteroarchitecture has been fabricated with reduced graphene oxide (NTS-rGO) and carbon nanotubes (NTS-CNTs) via a scalable and green hydrothermal route. In the successive hydrothermal treatment, the sulfur ions released from sodium sulfide react with nickel and tin ions to produce NTS heterostructure and provide a synergistic effect. The morphology displays nucleation of multiple nanoseeds, which grows into nanosheets of NTS for which rGO behaves as a template growth and CNT mesh befits the bridge to link the heterostructure of NTS. For NTS-rGO and NTS-CNTs NCs, the initial charge capacity was measured as 402 and 447 mA h g–1 at a rate of 0.05 C, respectively. Furthermore, CNTs act as a passivation layer and can accommodate structural integrity and prevent nanoparticles from aggregation during prolonged cycling; hence, NTS-CNTs displays ultra-cycling stability with a Coulombic efficiency of 100%, illuminating the synergistic effect among NTS and CNT unique patterns. The charge-transfer resistance is noticed to be the lowest for hybrid heterostructural NTS-CNTs (403.2 Ω) as compared to NTS-rGO and pure NTS (526.7 and 605.9 Ω), which effectively increase the charge transportation. The transition between diffusion and capacitive currents validates that charge storage is mainly pseudocapacitive at elevated scan rates in NTS-CNTs anode which is driven by finding of swift Na ion diffusion and rapid near-surface Na storage compared to pure NTS and NTS-rGO.

Ecotoxicological properties of functionalized magnetic graphene oxide and multiwall carbon nanotubes in Daphnia magna

In this investigation, we analyzed the nanotoxicity of two magnetic nanohybrids made of nanomaghemite dispersed in activated multiwall carbon nanotubes (JA1) and in graphene oxide (JA2), and we studied their influences on the water flea Daphnia magna that is part of the zooplankton, base of the food chain and of an utmost importance for the ecological balance. Before the toxicological studies, both nanohybrids were structurally, vibrationally, hyperfine, and magnetically characterized respectively with X-ray diffraction, scanning and transmission electron microscopy, Raman spectroscopy, 57Fe Mössbauer spectrometry, and vibrating sample magnetometry. Transmission electron microscopy gave the particle size distribution histogram with mean particle sizes of 13.8 (6) and 10.4 (2) nm for the nanomaghemite phase in the JA1 and JA2 nanohybrids, respectively. Raman analysis showed the presence of the nanomaghemite phase that has a threshold laser power of 0.71 mW for the γ→α structural phase transition. It was demonstrated that an increase of laser power produced defects and misalignments of the multi-walled carbon nanotubes causing nanomaghemite thermal activation in the JA1 nanohybrid, while the graphene oxide phase was detected by Raman spectroscopy and scanning electron microscopy, this last showed that graphene oxide sheets acting as a template for nanomaghemite growth in the JA2 nanohybrid. 57Fe Mössbauer spectrometry and magnetization data confirmed the presence of nanomaghemite nanoparticles with high magnetocrystalline anisotropy. Daphnids were cultured and exposed to different concentrations of both nanohybrids to obtain the median lethal concentration and morphological data. The lethal concentration values were 381.8 mg L−1 for the magnetic JA1 and 0.94 mg L−1 for JA2 nanohybrid. The results of the morphological measurements showed a negative influence for high concentrations of the nanohybrids, while low concentrations have shown biocompatibility with aquatic life.

All-around encapsulation of silicene.

Silicene or the two-dimensional (2D) graphene-like silicon allotrope has recently emerged as a promising candidate for various applications in nanotechnology. However, concerns on the silicene stability still persist to date and need to be addressed aiming at the fabrication of competing and durable silicene-based devices. Here, we present an all-around encapsulation methodology beyond the current state-of-the-art silicene configuration, namely silicene sandwiched in between a capping layer (e.g., Al2O3) and the supporting substrate (e.g., Ag). In this framework, the insertion of one or two sacrificial 2D Sn layers enables the realization of different atomically thin encapsulation schemes, preserving the pristine properties of silicene while decoupling it from the growth template. On one hand, the epitaxy of a 2D Sn layer before silicene allows for the removal of the Ag substrate with no effect on silicene which in turn can be easily gated, for example, with an oxide layer on its top face. On the other hand, a full 2D encapsulation scheme, where top and bottom faces of silicene are protected by 2D Sn layers, gives rise to an atomically thin and cm2-scaled membrane preventing degradation of silicene for months. Both schemes thus constitute an advancement for the silicene stability and encapsulation in ambient conditions, paving the way to further exploitation in flexible electronics and photonics.

Construction of Co@N-CNTs grown on N-MoxC nanosheets for separator modification to enhance adsorption and catalytic conversion of polysulfides in Li–S batteries

A multi-dimensional hybrid Co@N-CNTs/N-MoxC framework is fabricated by using Mo2C MXenes as a conversion and growth template, and the mechanisms of inhibiting the shuttle effect and catalyzing the conversion of polysulfides are reasonably proposed.

Molecular template growth of organic heterojunctions to tailor visual neuroplasticity for high performance phototransistors with ultralow energy consumption.

The optical and charge transport properties of organic semiconductors are strongly influenced by their morphology and molecular structures. Here we report the influence of a molecular template strategy on anisotropic control via weak epitaxial growth of a semiconducting channel for a dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT)/para-sexiphenyl (p-6P) heterojunction. The aim is to improve charge transport and trapping, to enable tailoring of visual neuroplasticity. The proposed phototransistor devices, comprising a molecular heterojunction with optimized molecular template thickness, exhibited an excellent memory ratio (ION/IOFF) and retention characteristics in response to light stimulation, owing to the enhanced orientation/packing of DNTT molecules and a favorable match between the LUMO/HOMO levels of p-6P and DNTT. The best performing heterojunction exhibits visual synaptic functionalities, including an extremely high pair-pulse facilitation index of ∼206%, ultralow energy consumption of 0.54 fJ, and zero-gate operation, under ultrashort pulse light stimulation to mimic human-like sensing, computing, and memory functions. An array of heterojunction photosynapses possess a high degree of visual pattern recognition and learning, to mimic the neuroplasticity of human brain activities through a rehearsal learning process. This study provides a guide to the design of molecular heterojunctions for tailoring high-performance photonic memory and synapses for neuromorphic computing and artificial intelligence systems.