Multilayer 3D Research Articles

3D Crystal Construction by Single-Crystal 2D Material Supercell Multiplying.

2D stacking presents a promising avenue for creating periodic superstructures that unveil novel physical phenomena. While extensive research has focused on lateral 2D material superstructures formed through composition modulation and twisted moiré structures, the exploration of vertical periodicity in 2D material superstructures remains limited. Although weak van der Waals interfaces enable layer-by-layer vertical stacking, traditional methods struggle to control in-plane crystal orientation over large areas, and the vertical dimension is constrained by unscalable, low-throughput processes, preventing the achievement of global order structures. In this study, a supercell multiplying approach is introduced that enables high-throughput construction of 3D superstructures on a macroscopic scale, utilizing artificially stacked single-crystalline 2D multilayers as foundational repeating units. By employing wafer-scale single-crystalline 2D materials and referencing the crystal orientation of substrates, the method ensures precise alignment of crystal orientation within and across each supercell, thereby achieving controllable periodicity along all three axes. A centimeter-scale 3R-MoS₂ crystal is successfully constructed, comprising over 200 monolayers of single-crystalline MoS₂, through a bottom-up stacking process. Additionally, the approach accommodates the integration of amorphous oxide, enabling the assembly of 3D non-linear optical crystals with quasi-phase matching. This method paves the way for the bottom-up construction of macroscopic artificial 3D crystals with atomic plane precision, enabling tailored optical, electrical, and thermal properties and advancing the development of novel artificial materials and high-performance applications.

Coordination of Ultralow Permittivity and Higher Thermal Conductivity of Polyimide Induced by Unique Interfacial Self‐Assembly Behavior

AbstractUpgrading the available dielectric materials is the most effective approach to solve the poor quality of signal transmission and heat buildup caused by high density integration. In this work, a design strategy for multilayer 3D porous composite networks is proposed, relying on the self‐assembly effect of “crystal‐like phase” to achieve the synergistic optimization of low permittivity and high thermal conductivity of polyimide. The obtained three‐layer porous polyimide composite film (PSLS) features an ultralow permittivity of 1.89, an in‐plane thermal conductivity as high as 13.58 W m−1 K−1, and maintains well electrical insulating property. Inspiringly, the first digital thermoacoustic generator with wide frequency response has been designed based on PSLS film. It achieves sound pressure levels up to 60.1 dB in the 20–100 kHz range and integrates the efficient sound generation of an ultrasonic generator with real‐time display. This work will provide a novel concept material for the smart electronics and electrical fields.

A Bottom-Up Approach to Assemble Cell-Laden Biomineralized Nanofiber Mats into 3D Multilayer Periosteum Mimics for Bone Regeneration.

The creation of complex multilayer periosteal graft structures is challenging. This study introduced a novel bottom-up approach to assemble cell-laden nanofiber mats into a three-dimensional (3D) multilayer periosteum mimic, successfully replicating the hierarchical complexity of the natural periosteum. These nanofiber mats, which were fabricated by electrospinning, surface modification, and stimulated body fluid (SBF) immersion, are composed of nanoscale polycaprolactone (PCL) fibers coated with a mineralized collagen layer along the fiber orientation. They closely resembled the natural periosteal matrix, thereby promoting osteogenic differentiation of rat bone marrow mesenchymal stem cells (rBMSCs) in vitro. The biomimetic periosteum, constructed via layer-by-layer assembly, offered advantages such as a multilayer nanofibrous structure, controlled cell distribution, a reservoir for osteoprogenitors, and enhanced pro-osteogenic potential. The rat calvarial bone defect model confirmed its potent bone repair capacity. This study presents an efficient approach to construct tissue-engineered periosteum mimics, holding promise for serving as periosteal grafts in orthopedic applications.

EXPRESSO: a multi-omics database to explore multi-layered 3D genomic organization.

The three-dimensional (3D) organization of the human genome plays a crucial role in gene regulation. EXPloration of Regulatory Epigenome with Spatial and Sequence Observations (EXPRESSO) is a novel multi-omics database for exploration and visualization of multi-layered 3D genomic features across 46 different human tissues. Integrating 1360 3D genomic datasets (Hi-C, HiChIP, ChIA-PET) and 842 1D genomic and transcriptomic datasets (ChIP-seq, ATAC-seq, RNA-seq) from the same biosample, EXPRESSO provides a comprehensive resource for studying the interplay between 3D genome architecture and transcription regulation. This database offers diverse 3D genomic feature types (compartments, contact matrix, contact domains, stripes as diagonal lines extending from a genomic locus in contact matrix, chromatin loops, etc.) and user-friendly interface for both data exploration and download. Other key features include REpresentational State Transfer application programming interfaces for programmatic access, advanced visualization tools for 3D genomic features and web-based applications that correlate 3D genomic features with gene expression and epigenomic modifications. By providing extensive datasets and tools, EXPRESSO aims to deepen our understanding of 3D genomic architecture and its implications for human health and disease, serving as a vital resource for the research community. EXPRESSO is freely available at https://expresso.sustech.edu.cn.

Double-crosslinked dECM bioink to print a self-sustaining 3D multi-layered aortic-like construct

Cardiovascular disease is the leading cause of death worldwide, with related mortality increasing from 12.1 million to 18.6 million in the past 30 years.To address the supply limitation of autologous vascular grafts and overcome the limits of current treatment options, 3D bioprinting techniques have been investigated.This study aimed at introducing a self-supporting and multi-layered 3D bioprinted construct as a promising alternative for large-blood vessel replacement. To this end, we developed an alginate-gelatin bioink enriched with decellularized extracellular matrix (dECM) of porcine aorta combined with a two-step crosslinking process. We investigated the feasibility of achieving structural stability and shape fidelity of the bioprinted construct over time through rheological characterization, printability tests, and degradation tests.According to the results of rheology and printability tests, dECM-enriched bioink combined with the double-crosslinking process (internal and external crosslink) showed good printability and high shape fidelity, withstanding more than 35 layers without the need for support. Moreover, the bioprinted construct preserved its structural stability over time, retaining a wall thickness comparable to that of the native aorta. Finally, immortalized mouse fibroblasts embedded in the bioink were well adhered to the bioink and alive over time. The double-crosslinked bioink represents an impactful strategy to produce an alternative conduit with the native hierarchical structure of the large blood vessels.

β-Ca3(PO4)2- Ca9.95Li1.05(PO4)7 lamellar microstructure by chemical etching: Synthesis, characterization and in vitro bioactivity

In this study, new multilayer 3D porous scaffolds were designed with a core composed of Ca3O5Si (C3S) and external layers composed of Ca5Li2(PO4)4. Scaffolds' surface topography was modified to reveal a lamellar microstructure by applying chemical etching. Scaffolds were characterized by X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy with Energy Dispersive X-ray spectroscopy (FESEM/EDX), Fourier Transform Infrared Spectroscopy (FTIR) and Mercury Porosimetry. In vitro bioactivity was evaluated by immersing scaffolds in simulated body fluid (SBF) at 1, 3 and 7 days. Scaffolds presented calcium pyrophosphate, β-tricalcium phosphate (β-TCP), nonstoichiometric and stoichiometric calcium/lithium phosphate as the main phases. The calcium pyrophosphate and stoichiometric calcium/lithium phosphate in the external layer were eliminated by the chemical etching process, which revealed the lamellar microstructure. Lamellar width varied from 1.44 μm to 0.73 μm depending on the chemical etching time. The obtained mechanical strength results influenced samples’ macroporosity, which ranged from 50 % to 64 %. These samples also exhibited microporosity between 30.3 % and 49.0 %. During the bioactivity test, all the chemically etched samples showed a hydroxyapatite-like (HA-like) precipitate, except for the sample chemically etched for 30 s at day 1. At day 7, the lamellar microstructure in the samples chemically etched for 30 s and 45 s (C-30 s and C-45 s) was completely covered by the HA-like precipitate, whereas the lamellar microstructure in the sample chemically etched for 60 s (C-60 s) was only partially covered by the HA-like precipitate.

Strain distribution analysis in multilayered 3D printed beam during 3-point bending process

Strain distribution analysis in multilayered 3D printed beam during 3-point bending process

Van der Waals Multilayered Films: Wafer‐Scale Synthesis and Applications in Electronics and Optoelectronics

Abstract2D materials possess significant potential across various applications, with physical and chemical properties that can be effectively modulated by their thickness, enabling tailored optimization for specific uses. For instance, 2D monolayers are ideal for transparent and flexible electronics, while 2D multilayers are more suitable for solar cells and high‐speed devices. Although scalable methods for synthesizing large‐area 2D materials and their applications have been developed, most research has focused on monolayers, with comparatively limited efforts directed toward multilayers. This review provides an overview of the emerging field of 2D multilayers, revisiting the analysis of layer‐dependent properties to determine the optimal material thickness for various applications. It introduces representative techniques for synthesizing 2D multilayer films and presents applications where multilayer structures demonstrate superior performance compared to monolayers, particularly in electronics and optoelectronics. The review advocates for the development of synthesis and integration methods for 2D multilayers, calling for a shift in research focus toward these materials to enhance their technological impact and unlock new industrial applications.

Improving Thermosensitive Bioink Scaffold Fabrication with a Temperature-Regulated Printhead in Robot-Assisted In Situ Bioprinting System.

In situ bioprinting enables precise 3D printing inside the human body using modified bioprinters with thermosensitive bioinks such as gelatin methacrylate (GelMA). However, these devices lack refined temperature-regulated mechanisms essential for ensuring bioink viscosity, as compared to traditional bio-3D printers. Addressing this challenge, this study presents a temperature-regulated printhead designed to improve the fabrication of thermosensitive bioink scaffolds in in situ bioprinting, integrated into a UR5 robotic arm. Featuring a closed-loop system, it achieves a temperature steady error of 1 °C and a response time of approximately 1 min. The effectiveness of the printer was validated by bioprinting multilayer lattice 3D bioscaffolds. Comparisons were made with or without temperature control using different concentrations of GelMA + LAP. The deformation of the bioscaffolds under both conditions was analyzed, and cell culture tests were conducted to verify viability. Additionally, the rheology and mechanical properties of GelMA were tested. A final preliminary in situ bioprinting experiment was conducted on a model of a damaged femur to demonstrate practical application. The fabrication of this printhead is entirely open source, facilitating easy modifications to accommodate various robotic arms. We encourage readers to advance this prototype for application in increasingly complex in situ bioprinting situations, especially those utilizing thermosensitive bioinks.

Internally-crosslinked alginate dialdehyde/alginate/gelatin-based hydrogels as bioprinting inks for prospective cardiac tissue engineering applications

Cardiovascular diseases represent a worldwide social and economic challenge, due to heart tissue limited regenerative capabilities. 3D bioprinted cell-laden constructs are a promising approach to develop patches for cardiac regeneration or in vitro models for new drug preclinical discovery and validation. However, the development of bioinks with optimal mechanical, rheological, and biological properties is still a challenge. Although alginate (Alg)-based bioinks have been extensively explored, such hydrogels lack cell adhesion properties and degradability. Additionally, 3D Alg structures are usually obtained by micro-extrusion bioprinting exploiting conventional external cross-linking methods, which introduce inhomogeneities and unpredictability in construct formation. This work exploits Alg internal ionic gelation mechanism to obtain homogeneous self-standing multilayered 3D printed constructs without employing support baths or post-printing crosslinking treatments, combining an insoluble calcium salt (calcium carbonate, CaCO3) with an acidifying agent (D-(+)-Glucono-1,5-lactone, GDL) to promote controlled release of calcium ions. Alg was blended with oxidized alginate (ADA) and gelatin (Gel) to achieve degradable and cell adhesive hydrogels for cardiac tissue engineering. Firstly, ADA/Alg bioink composition was tailored by varying polymer weight ratio (keeping ADA as the main component) and calcium ions concentration to achieve cardiac tissue-like viscoelastic properties. Then, the amount of Gel in ADA/Alg hydrogels was optimized to support adult human cardiac fibroblasts (AHCFs) adhesion, producing shear thinning inks with tunable viscoelastic properties (G’ 650-1300 Pa) and degradation profile (40-80% weight loss after 21 days in phosphate buffered saline, PBS) by varying Gel concentration. ADA/Alg/Gel hydrogels showed a shear thinning behavior suitable for 3D bioprinting and dependent on ink stabilization time, due to the gradual pH-triggered release of calcium ions over time. AHCFs-laden ADA/Alg/Gel bioinks could be successfully printed producing scaffolds with high shape fidelity and good cell viability post-printing. Finally, 3D AHCF-laden and H9C2-laden ADA/Alg/Gel bioinks with the highest gelatin content (25% w/w) allowed cell adhesion after 24 hours of incubation, showing potential application for cardiac tissue modelling. This research presented a comprehensive framework for advancing the design of bioink formulations enabling the printing of cell-adhesive and self-supporting constructs.

Sliding-reversible bandgap modulation in irreversible asymmetric multilayers

The electronic bandgap of a material is often fixed after fabrication. The capability to realize on-demand and nonvolatile control over the bandgap will unlock exciting opportunities for adaptive devices with enhanced functionalities and efficiency. We introduce a general design principle for on-demand and nonvolatile control of bandgap values, which utilizes reversible sliding-induced polarization driven by an external electric field to modulate the irreversible background polarization in asymmetric two-dimensional (2D) multilayers. The structural asymmetry can be conveniently achieved in homobilayers of Janus monolayers and heterobilayers of nonpolar monolayers, making the design principle applicable to a broad range of 2D materials. We demonstrate the versatility of this design principle using experimentally synthesized Janus metal dichalcogenide multilayers as examples. Our first-principles calculations show that the bandgap modulation can reach up to 0.3 eV and even support a semimetal-to-semiconductor transition. By integrating a ferroelectric monolayer represented by 1T″′-MoS2 into a bilayer, we show that the combination of intrinsic ferroelectricity and sliding ferroelectricity leads to multi-bandgap systems coupled to multi-step polarization switching. The sliding-reversible bandgap modulation offers an avenue to dynamically adjust the optical, thermal, and electronic properties of 2D materials through mechanical and electrical stimuli.

Iterative printing of bulk metal and polymer for additive manufacturing of multi-layer electronic circuits

In pursuing advancing additive manufacturing (AM) techniques for 3D objects, this study combines AM techniques for bulk metal and polymer on a single platform for one-stop printing of multilayer 3D electronic circuits with two novel aspects. The first innovation involves the embedded integration of electronic circuits by printing low-resistance electrical traces from bulk metal into polymer channels. Cross-section grinding results reveal (92 ± 5)% occupancy of electrically conductive traces in polymer channels despite the different thermal properties of the two materials. The second aspect encompasses the possibility of printing vertical bulk metal vias up to 10 mm in height with the potential for expansion, interconnecting electrically conductive traces embedded in different layers of the 3D object. The work provides comprehensive 3D printing design guidelines for successfully integrating fully embedded electrically conductive traces and the interconnecting vertical bulk metal vias. A smooth and continuous workflow is also introduced, enabling a single-run print of functional multilayer embedded 3D electronics. The design rules and the workflow facilitate the iterative printing of two distinct materials, each defined by unique printing temperatures and techniques. Observations indicate that conductive traces using molten metal microdroplets show a 12-fold reduction in resistance compared to nanoparticle ink-based methods, meaning this technique greatly complements multi-material additive manufacturing (MM-AM). The work presents insights into the behavior of molten metal microdroplets on a polymer substrate when printed through the MM-AM process. It explores their characteristics in two scenarios: When they are deposited side-by-side to form conductive traces and when they are deposited out-of-plane to create vertical bulk metal vias. The innovative application of MM-AM to produce multilayer embedded 3D electronics with bulk metal and polymer demonstrates significant potential for realizing the fabrication of free-form 3D electronics.

Vapor Growth of All-Inorganic 2D Ruddlesden-Popper Lead- and Tin-Based Perovskites.

The 2D Ruddlesden-Popper (RP) perovskites Cs2PbI2Cl2 (Pb-based, n = 1) and Cs2SnI2Cl2 (Sn-based, n = 1) stand out as unique and rare instances of entirely inorganic constituents within the more expansive category of organic/inorganic 2D perovskites. These materials have recently garnered significant attention for their strong UV-light responsiveness, exceptional thermal stability, and theoretically predicted ultrahigh carrier mobility. In this study, we synthesized Pb and Sn-based n = 1 2D RP perovskite films covering millimeter-scale areas for the first time, utilizing a one-step chemical vapor deposition (CVD) method under atmospheric conditions. These films feature perovskite layers oriented horizontally relative to the substrate. Multilayered Cs3Pb2I3Cl4 (Pb-based, n = 2) and Cs3Sn2I3Cl4 (Sn-based, n = 2) films were also obtained for the first time, and their crystallographic structures were refined by combining X-ray diffraction (XRD) and density functional theory (DFT) calculations. DFT calculations and experimental optical spectroscopy support band-gap energy shifts related to the perovskite layer thickness. We demonstrate bias-free photodetectors using the Sn-based, n = 1 perovskite with reproducible photocurrent and a fast 84 ms response time. The present work not only demonstrates the growth of high-quality all-inorganic multilayered 2D perovskites via the CVD method but also suggests their potential as promising candidates for future optoelectronic applications.

Multilayer 3D seismic attribute analysis and fault framework modeling of shallow extensional fault systems in the Delaware Basin

Shallow extensional fault systems within the southern Delaware Basin have gained the interest of Permian operators since published works noted them in 2019. These shallow extensional fault systems, referred to as “lineaments” by operators, are seismogenic hazards, pose significant hazards to drilling operations, and are associated with elevated water-oil ratios and H2S concentrations. Previous work using seismic attribute analysis has resulted in the successful mapping of extensional fault systems at the Ochoan/Guadalupian interface, whereas fault geometry, origin, and depth of penetration have remained elusive. First- and second-order ant tracking of the variance cube is rendered on multiple seismic horizons throughout an 856 km2 (approximately 330 mi2) depth-migrated 3D seismic reflection volume to expand the interpretation of the deformation zone at depth and guide a robust 3D fault model that forms the framework for the predictive model. A total of 60 previously undocumented features are identified in southwestern Reeves County — 56 penetrate the Ochoan/Guadalupian interface, 60 penetrate the middle Guadalupian, 29 penetrate the early Guadalupian, and 21 penetrate the early Leonardian. Structural modeling returns an average strike orientation of 318° north-northwest–south-southeast and an average dip of 84°. Spatial and temporal analysis of the model constrains the timing of extension to the Cenozoic. In contrast to previous studies, the improved depth of investigation of the 3D fault model allows for the correlation of documented drilling hazards with offset wastewater disposal wells along shared lineaments. Communication is indicated by H2S risking flags from mass spectrometry data along the vertical and horizontal sections of producing and injecting wells. Drilling data validates the seismic characterization and prediction of the 3D faulted architecture within the largest contiguous study of shallow extensional fault systems within the Delaware Basin and establishes a repeatable workflow for mitigating the negative impacts of shallow lineament geohazards on drilling operations and production profiles.

Enhanced Energy Density in a Heterostructure Capacitor of Multilayered PVDF and 2D Mica Nanocomposites

Enhanced Energy Density in a Heterostructure Capacitor of Multilayered PVDF and 2D Mica Nanocomposites

Bilayer Crystals of Trapped Ions for Quantum Information Processing

Trapped-ion systems are a leading platform for quantum information processing, but they are currently limited to 1D and 2D arrays, which imposes restrictions on both their scalability and their range of applications. Here, we propose a path to overcome this limitation by demonstrating that Penning traps can be used to realize remarkably clean bilayer crystals, wherein hundreds of ions self-organize into two well-defined layers. These bilayer crystals are made possible by the inclusion of an anharmonic trapping potential, which is readily implementable with current technology. We study the normal modes of this system and discover salient differences compared to the modes of single-plane crystals. The bilayer geometry and the unique properties of the normal modes open new opportunities—in particular, in quantum sensing and quantum simulation—that are not straightforward in single-plane crystals. Furthermore, we illustrate that it may be possible to extend the ideas presented here to realize multilayer crystals with more than two layers. Our work increases the dimensionality of trapped-ion systems by efficiently utilizing all three spatial dimensions, and it lays the foundation for a new generation of quantum information processing experiments with multilayer 3D crystals of trapped ions. Published by the American Physical Society 2024

Creation of Grooved Tissue Engineering Scaffolds from Architectured Multilayer Polymer Composites by a Tuneable One-Step Degradation Process.

The surface properties of biomaterials interact directly with biological systems, influencing cellular responses, tissue integration, and biocompatibility. Surface topography plays a critical role in cardiac tissue engineering by affecting electrical conductivity, cardiomyocyte alignment, and contractile function. Current methods for controlling surface properties and topography in cardiac tissue engineering scaffolds are limited, expensive, and lack precision. This study introduces a low-cost, one-step degradation process to create scaffolds with well-defined micro-grooves from multilayered 3D printed poly(lactic acid)/thermoplastic polyurethane composites. The approach provides control over erosion rate and surface morphology, allowing easy tuning of scaffold topographical cues for tissue engineering applications. The findings reported in this study provide a library of easily tuneable scaffold topographical cues. A strong dependence of neonatal rat cardiomyocyte (NRCM) contact guidance with the multilayers' dimension and shape in partially degraded polylactic acid (PLA)/thermoplastic polyurethane (TPU) samples is observed. NRCMs cultured on samples with a layer thickness of 13 ± 2µm and depth of 4.7 ± 0.2µm demonstrate the most regular contractions. Hence, the proposed fabrication scheme can be used to produce a new generation of biomaterials with excellent controllability determined by multilayer thickness, printing parameters, and degradation treatment duration.

High Efficiency of Exciton-Polariton Lasing in a 2D Multilayer Structure.

We have placed a van der Waals homostructure, formed by stacking three two-dimensional layers of WS2 separated by insulating hBN, similar to a multiple-quantum well structure, inside a microcavity, which facilitates the formation of quasiparticles known as exciton-polaritons. The polaritons are a combination of light and matter, allowing laser emission to be enhanced by nonlinear scattering, as seen in prior polariton lasers. In the experiments reported here, we have observed laser emission with an ultralow threshold. The threshold was approximately 59 nW/μm2, with a lasing efficiency of 3.82%. These findings suggest a potential for efficient laser operations using such homostructures.

Synthesis of 2D Gallium Sulfide with Ultraviolet Emission by MOCVD.

Two-dimensional (2D) materials exhibit the potential to transform semiconductor technology. Their rich compositional and stacking varieties allow tailoring materials' properties toward device applications. Monolayer to multilayer gallium sulfide (GaS) with its ultraviolet band gap, which can be tuned by varying the layer number, holds promise for solar-blind photodiodes and light-emitting diodes as applications. However, achieving commercial viability requires wafer-scale integration, contrasting with established, limited methods such as mechanical exfoliation. Here the one-step synthesis of 2D GaS is introduced via metal-organic chemical vapor deposition on sapphire substrates. The pulsed-mode deposition of industry-standard precursors promotes 2D growth by inhibiting the vapor phase and on-surface pre-reactions. The interface chemistry with the growth of a Ga adlayer that results in an epitaxial relationship is revealed. Probing structure and composition validate thin-film quality and 2D nature with the possibility to control the thickness by the number of GaS pulses. The results highlight the adaptability of established growth facilities for producing atomically thin to multilayered 2D semiconductor materials, paving the way for practical applications.

Enhancing tendon-bone integration and healing with advanced multi-layer nanofiber-reinforced 3D scaffolds for acellular tendon complexes

Advancements in tissue engineering are crucial for successfully healing tendon-bone connections, especially in situations like anterior cruciate ligament (ACL) restoration. This study presents a new and innovative three-dimensional scaffold, reinforced with nanofibers, that is specifically intended for acellular tendon complexes. The scaffold consists of a distinct layered arrangement comprising an acellular tendon core, a middle layer of polyurethane/type I collagen (PU/Col I) yarn, and an outside layer of poly (L-lactic acid)/bioactive glass (PLLA/BG) nanofiber membrane. Every layer is designed to fulfill specific yet harmonious purposes. The acellular tendon core is a solid structural base and a favorable environment for tendon cell functions, resulting in considerable tensile strength. The central PU/Col I yarn layer is vital in promoting the tendinogenic differentiation of stem cells derived from tendons and increasing the expression of critical tendinogenic factors. The external PLLA/BG nanofiber membrane fosters the process of bone marrow mesenchymal stem cells differentiating into bone cells and enhances the expression of markers associated with bone formation. Our scaffold's biocompatibility and multi-functional design were confirmed through extensive in vivo evaluations, such as histological staining and biomechanical analyses. These assessments combined showed notable enhancements in ACL repair and healing. This study emphasizes the promise of multi-layered nanofiber scaffolds in orthopedic tissue engineering and also introduces new possibilities for the creation of improved materials for regenerating the tendon-bone interface.