Stretchable All‐Gel‐State Fiber‐Shaped Supercapacitors Enabled by Macromolecularly Interconnected 3D Graphene/Nanostructured Conductive Polymer Hydrogels

Nanostructured conductive polymer hydrogels (CPHs) have been extensively applied in energy storage owing to their advantageous features, such as excellent electrochemical activity and relatively high electrical conductivity, yet the fabrication of self‐standing and flexible electrode‐based CPHs is still hampered by their limited mechanical properties. Herein, macromolecularly interconnected 3D graphene/nanostructured CPH is synthesized via self‐assembly of CPHs and graphene oxide macrostructures. The 3D hybrid hydrogel shows uniform interconnectivity and enhanced mechanical properties due to the strong macromolecular interaction between the CPHs and graphene, thus greatly reducing aggregation in the fiber‐shaping process. A proof‐of‐concept all‐gel‐state fibrous supercapacitor based on the 3D polyaniline/graphene hydrogel is fabricated to demonstrate the outstanding flexibility and mouldability, as well as superior electrochemical properties enabled by this 3D hybrid hydrogel design. The proposed device can achieve a large strain (up to ≈40%), and deliver a remarkable volumetric energy density of 8.80 mWh cm^?3 (at power density of 30.77 mW cm^?3), outperforming many fiber‐shaped supercapacitors reported previously. The all‐hydrogel design opens up opportunities in the fabrication of next‐generation wearable and portable electronics.     

Laminated Object Manufacturing of 3D‐Printed Laser‐Induced Graphene Foams

Laser‐induced graphene (LIG), a graphene structure synthesized by a one‐step process through laser treatment of commercial polyimide (PI) film in an ambient atmosphere, has been shown to be a versatile material in applications ranging from energy storage to water treatment. However, the process as developed produces only a 2D product on the PI substrate. Here, a 3D LIG foam printing process is developed on the basis of laminated object manufacturing, a widely used additive‐manufacturing technique. A subtractive laser‐milling process to yield further refinements to the 3D structures is also developed and shown here. By combining both techniques, various 3D graphene objects are printed. The LIG foams show good electrical conductivity and mechanical strength, as well as viability in various energy storage and flexible electronic sensor applications.     

Patterning Graphene Surfaces with Iron‐Oxide‐Embedded Mesoporous Polypyrrole and Derived N‐Doped Carbon of Tunable Pore Size

This study develops a novel strategy, based on block copolymer self‐assembly in solution, for preparing two‐dimensional (2D) graphene‐based mesoporous nanohybrids with well‐defined large pores of tunable sizes, by employing polystyrene‐block‐poly(ethylene oxide) (PS‐b‐PEO) spherical micelles as the pore‐creating template. The resultant 2D nanohybrids possess a sandwich‐like structure with Fe₂O₃ nanoparticle‐embedded mesoporous polypyrrole (PPy) monolayers grown on both sides of reduced graphene oxide (rGO) nanosheets (denoted as mPPy‐Fe₂O₃@rGO). Serving as supercapacitor electrode materials, the 2D ternary nanohybrids exhibit controllable capacitive performance depending on the pore size, with high capacitance (up to 1006 F/g at 1 A/g), good rate performance (750 F/g at 20 A/g) and excellent cycling stability. Furthermore, the pyrolysis of mPPy‐Fe₂O₃@rGO at 800 °C yields 2D sandwich‐like mesoporous nitrogen‐doped carbon/Fe₃O₄/rGO (mNC‐Fe₃O₄@rGO). The mNC‐Fe₃O₄@rGO nanohybrids with a mean pore size of 12 nm show excellent electrocatalytic activity as an oxygen reduction reaction (ORR) catalyst with a four‐electron transfer nature, a high half‐wave‐potential of +0.84 V and a limiting current density of 5.7 mA/cm², which are well comparable with those of the best commercial Pt/C catalyst. This study takes advantage of block copolymer self‐assembly for the synthesis of 2D multifunctional mesoporous nanohybrids, and helps to understand the control of their structures and electrochemical performance.     

Sustainable Solid‐State Supercapacitors Made of 3D‐Poly(3,4‐ethylenedioxythiophene) and κ‐Carrageenan Biohydrogel

3D‐Poly(3,4‐ethylenedioxythiophene) (PEDOT) electrodes are prepared using the multi‐step template‐assisted approach. Specifically, poly(lactic acid) nano‐ and microfibers collected on a previously polymerized PEDOT film are used as templates for PEDOT nano‐ and microtubes, respectively. Morphological analysis of the samples indicates that 3D‐PEDOT electrodes obtained using a low density of templates, in which nano‐ and microtubes are clearly identified, exhibit higher porosity, and specific surface than conventional 2D‐PEDOT electrodes. However, a pronounced leveling effect is observed when the density of templates is high. Thus, electrodes with microtubes still present a 3D‐morphology but much less marked than those prepared using a low density of PLA microfibers, whereas the morphology of those with nanotubes is practically identical to that of films. Electrochemical studies prove that solid supercapacitors prepared using 3D‐PEDOT electrodes and κ‐carrageenan biohydrogel as electrolytic medium, exhibit higher ability to exchange charge reversibly and to storage charge than the analogues prepared with 2D‐electrodes. Furthermore, solid devices prepared using 3D‐electrodes and κ‐carrageenan biohydrogel exhibit very similar specific capacitances that those obtained using the same electrodes and a liquid electrolyte (i.e., acetonitrile solution with 0.1 M LiClO₄). These results prove that the success of 3D‐PEDOT electrodes is independent of the electrolytic medium.

     

A SERS‐Assisted 3D Barcode Chip for High‐Throughput Biosensing

A surface enhanced Raman scattering (SERS)‐assisted 3D barcode chip has been developed for high‐throughput biosensing. The 3D barcode is realized through joint 2D spatial encoding with the Raman spectroscopic encoding, which stores the SERS fingerprint information in the format of a 2D array. Here, the concept of SERS‐assisted 3D barcode is demonstrated through multiplex immunoassay, where simultaneous detection of multiple targets in different samples has been achieved using a microfluidic platform. First, multiple proteins in different samples are spatially separated using a microfluidic patterned antibody barcode substrate, forming a 2D hybridization array. Then the SERS probes are used to identify and quantify the proteins. As different SERS probes are labeled with different Raman reporters, they could be employed as “SERS tags” to incorporate spectroscopic information into the 3D barcode. In this 3D barcode, the 2D spatial information helps to differentiate the samples and targets while the SERS information allows quantitative multiplex detection. It is found that the SERS‐assisted 3D barcode chip can not only accomplish one‐step multiplex detection within 30 min but also achieve an ultrasensitivity down to 10 fg mL^?1 (≈70 aM), which is expected to provide a promising tool for high‐throughput biomedical applications.     

An accelerated surface discretization‐based BEM approach for non‐homogeneous linear problems in 3‐D complex domains

For non‐homogeneous or non‐linear problems, a major difficulty in applying the boundary element method (BEM) is the treatment of the volume integrals that arise. An accurate scheme that requires no volume discretization is highly desirable. In this paper, we describe an efficient approach, based on the precorrected‐FFT technique, for the evaluation of volume integrals resulting from non‐homogeneous linear problems. In this approach, the 3‐D uniform grid constructed initially to accelerate surface integration is used as the baseline mesh for the evaluation of volume integrals. As such, no volume discretization of the interior problem domain is necessary. Moreover, with the uniform 3‐D grid, the matrix sparsification techniques (such as the precorrected‐FFT technique used in this work) can be extended to accelerate volume integration in addition to surface integration, thus greatly reducing the computational time. The accuracy and efficiency of our approach are demonstrated through several examples. A 3‐D accelerated BEM solver for Poisson equations has been developed and has been applied to a 3‐D multiply‐connected problem with complex geometries. Good agreement between simulation results and analytical solutions has been obtained. Copyright © 2005 John Wiley & Sons, Ltd.     

Thiophene‐Bridged Donor–Acceptor sp2‐Carbon‐Linked 2D Conjugated Polymers as Photocathodes for Water Reduction

Photoelectrochemical (PEC) water reduction, converting solar energy into environmentally friendly hydrogen fuel, requires delicate design and synthesis of semiconductors with appropriate bandgaps, suitable energy levels of the frontier orbitals, and high intrinsic charge mobility. In this work, the synthesis of a novel bithiophene‐bridged donor–acceptor‐based 2D sp²‐carbon‐linked conjugated polymer (2D CCP) is demonstrated. The Knoevenagel polymerization between the electron‐accepting building block 2,3,8,9,14,15‐hexa(4‐formylphenyl) diquinoxalino[2,3‐a:2′,3′‐c]phenazine (HATN‐6CHO) and the first electron‐donating linker 2,2′‐([2,2′‐bithiophene]‐5,5′‐diyl)diacetonitrile (ThDAN) provides the 2D CCP‐HATNThDAN (2D CCP‐Th). Compared with the corresponding biphenyl‐bridged 2D CCP‐HATN‐BDAN (2D CCP‐BD), the bithiophene‐based 2D CCP‐Th exhibits a wide light‐harvesting range (up to 674 nm), a optical energy gap (2.04 eV), and highest energy occupied molecular orbital–lowest unoccupied molecular orbital distributions for facilitated charge transfer, which make 2D CCP‐Th a promising candidate for PEC water reduction. As a result, 2D CCP‐Th presents a superb H₂‐evolution photocurrent density up to ≈7.9 µA cm^?2 at 0 V versus reversible hydrogen electrode, which is superior to the reported 2D covalent organic frameworks and most carbon nitride materials (0.09–6.0 µA cm^?2). Density functional theory calculations identify the thiophene units and cyano substituents at the vinylene linkage as active sites for the evolution of H₂.     

Effects of approximations in analyses of beams of open thin‐walled cross‐section—part II: 3‐D non‐linear behaviour

In a companion paper, the effects of approximations in the flexural‐torsional stability analysis of beams was studied, and it was shown that a second‐order rotation matrix was sufficiently accurate for a flexural‐torsional stability analysis. However, the second‐order rotation matrix is not necessarily accurate in formulating finite element model for a 3‐D non‐linear analysis of thin‐walled beams of open cross‐section. The approximations in the second‐order rotation matrix may introduce ‘self‐straining’ due to superimposed rigid‐body motions, which may lead to physically incorrect predictions of the 3‐D non‐linear behaviour of beams. In a 3‐D non‐linear elastic–plastic analysis, numerical integration over the cross‐section is usually used to check the yield criterion and to calculate the stress increments, the stress resultants, the elastic–plastic stress–strain matrix and the tangent modulus matrix. A scheme of the arrangement of sampling points over the cross‐section that is not consistent with the strain distributions may lead to incorrect predictions of the 3‐D non‐linear elastic–plastic behaviour of beams. This paper investigates the effects of approximations on the 3‐D non‐linear analysis of beams. It is found that a finite element model for 3‐D non‐linear analysis based on the second‐order rotation matrix leads to over‐stiff predictions of the flexural‐torsional buckling and postbuckling response and to an overestimate of the maximum load‐carrying capacities of beams in some cases. To perform a correct 3‐D non‐linear analysis of beams, an accurate model of the rotations must be used. A scheme of the arrangement of sampling points over the cross‐section that is consistent with both the longitudinal normal and shear strain distributions is needed to predict the correct 3‐D non‐linear elastic–plastic behaviour of beams. Copyright © 2001 John Wiley & Sons, Ltd.     

Three‐dimensional grayscale‐free topology optimization using a level‐set based r‐refinement method

In this paper, we propose a three‐dimensional (3D) grayscale‐free topology optimization method using a conforming mesh to the structural boundary, which is represented by the level‐set method. The conforming mesh is generated in an r‐refinement manner; that is, it is generated by moving the nodes of the Eulerian mesh that maintains the level‐set function. Although the r‐refinement approach for the conforming mesh generation has many benefits from an implementation aspect, it has been considered as a difficult task to stably generate 3D conforming meshes in the r‐refinement manner. To resolve this task, we propose a new level‐set based r‐refinement method. Its main novelty is a procedure for minimizing the number of the collapsed elements whose nodes are moved to the structural boundary in the conforming mesh; in addition, we propose a new procedure for improving the quality of the conforming mesh, which is inspired by Laplacian smoothing. Because of these novelties, the proposed r‐refinement method can generate 3D conforming meshes at a satisfactory level, and 3D grayscale‐free topology optimization is realized. The usefulness of the proposed 3D grayscale‐free topology optimization method is confirmed through several numerical examples. Copyright © 2017 John Wiley & Sons, Ltd.     

Biotinylated Photopolymers for 3D‐Printed Unibody Lab‐on‐a‐Chip Optical Platforms

The present work reports the first demonstration of straightforward fabrication of monolithic unibody lab‐on‐a‐chip (ULOCs) integrating bioactive micrometric 3D scaffolds by means of multimaterial stereolithography (SL). To this end, a novel biotin‐conjugated photopolymer is successfully synthesized and optimally formulated to achieve high‐performance SL‐printing resolution, as demonstrated by the SL‐fabrication of biotinylated structures smaller than 100 µm. By optimizing a multimaterial single‐run SL‐based 3D‐printing process, such biotinylated microstructures are incorporated within perfusion microchambers whose excellent optical transparency enables real‐time optical microscopy analyses. Standard biotin‐binding assays confirm the existence of biotin‐heads on the surfaces of the embedded 3D microstructures and allow to demonstrate that the biofunctionality of biotin is not altered during the SL‐printing, thus making it exploitable for further conjugation with other biomolecules. As a step forward, an in‐line optical detection system is designed, prototyped via SL‐printing and serially connected to the perfusion microchambers through customized world‐to‐chip connectors. Such detection system is successfully employed to optically analyze the solution flowing out of the microchambers, thus enabling indirect quantification of the concentration of target interacting biomolecules. The successful application of this novel biofunctional photopolymer as SL‐material enables to greatly extend the versatility of SL to directly fabricate ULOCs with intrinsic biofunctionality.     

Flexible 3D Porous MXene Foam for High‐Performance Lithium‐Ion Batteries

2D transition‐metal carbides and nitrides, named MXenes, are promising materials for energy storage, but suffer from aggregation and restacking of the 2D nanosheets, which limits their electrochemical performance. In order to overcome this problem and realize the full potential of MXene nanosheets, a 3D MXene foam with developed porous structure is established via a simple sulfur‐template method, which is freestanding, flexible, and highly conductive, and can be directly used as the electrode in lithium‐ion batteries. The 3D porous architecture of the MXene foam offers massive active sites to enhance the lithium storage capacity. Moreover, its foam structure facilitates electrolyte infiltration for fast Li⁺ transfer. As a result, this flexible 3D porous MXene foam exhibits significantly enhanced capacity of 455.5 mAh g^?1 at 50 mA g^?1, excellent rate performance (101 mAh g^?1 at 18 A g^?1), and superior ultralong‐term cycle stability (220 mAh g^?1 at 1 A g^?1 after 3500 cycles). This work not only demonstrates the great superiority of the 3D porous MXene foam but also proposes the sulfur‐template method for controllable constructing of the 3D foam from 2D nanosheets at a relatively low temperature.     

Freestanding 3D Graphene–Nickel Encapsulated Nitrogen‐Rich Aligned Bamboo Like Carbon Nanotubes for High‐Performance Supercapacitors with Robust Cycle Stability

3D hierarchical structures are reported based on graphene–nickel encapsulated nitrogen‐rich aligned bamboo like carbon nanotubes, which show not only high‐performance supercapacitance behavior but also a great robust cyclic stability. A facile synthesis route is developed of 2D nickel oxide decorated functionalized graphene nanosheets (2D‐NiO‐f:GNSs) hybrids and 3D nitrogen doped bamboo‐shaped carbon nanotubes (NCNTs) vertically standing on the functionalized graphene nanosheets (3D‐NCNT@f:GNSs) by using a thermal decomposition method. The chemical reduction and morphology‐dependent electrochemical response are investigated. The enhanced specific capacitance of 3D‐NCNT@f:GNSs as compared to that of 2D‐NiO‐f:GNSs suggests the synergistic effects and indicates the importance of energy storage and superior long‐term cycling performance that are achieved. This 3D‐NCNT@f:GNSs hybrid shows a remarkable cycling stability with a maximum power density of 12.32 kW kg⁻¹ and maximum energy density of 109.13 Wh kg⁻¹ due to the good connection of NCNT and f:GNSs. This unique 3D nano network architecture enables the availability of large surface areas of NCNT, thus endowing the nanohybrids with high specific capacitance and excellent reusability.     

Mineral‐Templated 3D Graphene Architectures for Energy‐Efficient Electrodes

3D graphene networks have shown extraordinary promise for high‐performance electrochemical devices. Herein, the chemical vapor deposition synthesis of a highly porous 3D graphene foam (3D‐GF) using naturally abundant calcined Iceland crystal as the template is reported. Intriguingly, the Iceland crystal transforms to CaO monolith with evenly distributed micro/meso/macropores through the releasing of CO₂ at high temperature. Meanwhile, the hierarchical structure of the calcined template could be easily tuned under different calcination conditions. By precisely inheriting fine structure from the templates, the as‐prepared 3D‐GF possesses a tunable hierarchical porosity and low density. Thus, the hierarchical pores offer space for guest hybridization and provide an efficient pathway for ion/charge transport in typical energy conversion/storage systems. The 3D‐GF skeleton electrode hybridized with Ni(OH)₂/Co(OH)₂ through an optimal electrodeposition condition exhibits a high specific capacitance of 2922.2 F g⁻¹ at a scan rate of 10 mV s⁻¹, and 2138.4 F g⁻¹ at a discharge current density of 3.1 A g⁻¹. The hybrid 3D‐GF symmetry supercapacitor shows a high energy density of 83.0 Wh kg⁻¹ at a power density of 1011.3 W kg⁻¹ and 31.4 Wh kg⁻¹ at a high power density of 18 845.2 W kg⁻¹. The facile fabrication process enables the mass production of hierarchical porous 3D‐GF for high‐performance supercapacitors.     

Silver‐Quantum‐Dot‐Modified MoO3 and MnO2 Paper‐Like Freestanding Films for Flexible Solid‐State Asymmetric Supercapacitors

Free‐standing paper‐like thin‐film electrodes have great potential to boost next‐generation power sources with highly flexible, ultrathin, and lightweight requirements. In this work, silver‐quantum‐dot‐ (2–5 nm) modified transition metal oxide (including MoO₃ and MnO₂) paper‐like electrodes are developed for energy storage applications. Benefitting from the ohmic contact at the interfaces between silver quantum dots and MoO₃ nanobelts (or MnO₂ nanowires) and the binder‐free nature and 0D/1D/2D nanostructured 3D network of the fabricated electrodes, substantial improvements on the electrical conductivity, efficient ionic diffusion, and areal capacitances of the hybrid nanostructure electrodes are observed. With this proposed strategy, the constructed asymmetric supercapacitors, with Ag quantum dots/MoO₃ “paper” as anode, Ag quantum dots/MnO₂ “paper” as cathode, and neutral Na₂SO₄/polyvinyl alcohol hydrogel as electrolyte, exhibit significantly enhanced energy and power densities in comparison with those of the supercapacitors without modification of Ag quantum dots on electrodes; present excellent cycling stability at different current densities and good flexibility under various bending states; offer possibilities as high‐performance power sources with low cost, high safety, and environmental friendly properties.     

Rapid and Low‐Cost Prototyping of 3D Nanostructures with Multi‐Layer Hydrogen Silsesquioxane Scaffolds

A layer‐by‐layer (LBL) method can generate or approximate any three‐dimensional (3D) structure, and has been the approach for the manufacturing of complementary metal‐oxide‐semiconductor (CMOS) devices. However, its high cost precludes the fabrication of anything other than CMOS‐compatible devices, and general 3D nanostructures have been difficult to prototype in academia and small businesses, due to the lack of expensive facility and state‐of‐the‐art tools. It is proposed and demonstrated that a novel process that can rapidly fabricate high‐resolution three‐dimensional (3D) nanostructures at low cost, without requiring specialized equipment. An individual layer is realized through electron‐beam lithography patterning of hydrogen silsesquioxane (HSQ) resist, followed by planarization via spinning SU‐8 resist and etch‐back. A 4‐layer silicon inverse woodpile photonic crystal with a period of 650 nm and a 7‐layer HSQ scaffold with a period of 300 nm are demonstrated. This process provides a versatile and accessible solution to the fabrication of highly complex 3D nanostructures.     

Ultrathin Nitrogen‐Doped Carbon Layer Uniformly Supported on Graphene Frameworks as Ultrahigh‐Capacity Anode for Lithium‐Ion Full Battery

The designable structure with 3D structure, ultrathin 2D nanosheets, and heteroatom doping are considered as highly promising routes to improve the electrochemical performance of carbon materials as anodes for lithium‐ion batteries. However, it remains a significant challenge to efficiently integrate 3D interconnected porous frameworks with 2D tunable heteroatom‐doped ultrathin carbon layers to further boost the performance. Herein, a novel nanostructure consisting of a uniform ultrathin N‐doped carbon layer in situ coated on a 3D graphene framework (NC@GF) through solvothermal self‐assembly/polymerization and pyrolysis is reported. The NC@GF with the nanosheets thickness of 4.0 nm and N content of 4.13 at% exhibits an ultrahigh reversible capacity of 2018 mA h g^?1 at 0.5 A g^?1 and an ultrafast charge–discharge feature with a remarkable capacity of 340 mA h g^?1 at an ultrahigh current density of 40 A g^?1 and a superlong cycle life with a capacity retention of 93% after 10 000 cycles at 40 A g^?1. More importantly, when coupled with LiFePO₄ cathode, the fabricated lithium‐ion full cells also exhibit high capacity and excellent rate and cycling performances, highlighting the practicability of this NC@GF.     

Reaction‐Diffusion‐Mediated Photolithography for Designing Pseudo‐3D Microstructures

Microstructures with 3D features provide advanced functionalities in many applications. Reaction‐diffusion process has been employed in photolithography to produce pseudo‐3D microstructures in a reproducible manner. In this work, the influences of various parameters on growth behavior of polymeric structures are investigated and the use of the reaction‐diffusion‐mediated photolithography (RDP) is expanded to a wide range of structural dimensions. In addition, how a lens effect alters the growth behavior of microstructures in conjunction with reaction‐diffusion process is studied. For small separation between reaction sites in the array, ultraviolet (UV) exposure time is optimized along with the separation to avoid film or plateau formation. It is further proved that the RDP process is highly reproducible and applicable to various photocurable resins. In a demonstrative purpose, the use of microdomes created by the RDP process as microlens arrays is shown. The RDP process enables the production of pseudo‐3D microstructures even with collimated UV light in the absence of complex optical setups, thereby potentially serving as a useful means to create micropatterns and particles with unique structural features.     

Modelling of Protein‐Protein Interactions of Bone Morphogenetic Protein‐2 (BMP‐2) by 3D‐Rapid Prototyping

Recently we were able to apply the technique of 3D‐Rapid Prototyping (3D‐RP) to the construction of highly accurate three‐dimensional plastic models of biomolecules [Laub, M. et al. (2001), Materialwiss. Werkstofftech. 32, 926]. These models are derived from x‐ray crystallographic data and therefore represent exact replicas of the depicted molecules. Due to their accuracy these models should be suitable for the modelling of protein‐protein‐interactions. In a first study using 3D‐Rapid Prototyping models of bone morphogenetic protein‐2 (BMP‐2) we were able to identify a novel structural motive on the concave side of this protein which we termed anthelix since a left‐handed helix (radius ca. 0.8–1 nm, pitch 8–9 nm) can be fitted into this groove. Based on these structural findings we identified a 15mer polypeptide (KNMTPYRSPPPYVPP) from the Brookhaven database as a potential physiological ligand. Molecular docking studies using a geometric recognition approach confirmed the anthelix as a possible binding site for this peptide. However in affinity chromatography experiments no binding between BMP‐2 and the immobilized peptide was observed. As the question arose whether 3D‐Rapid Prototyping is in general suitable for modelling protein‐protein interaction we used dimeric BMP‐2 to study exemplary monomer‐dimer interaction. Molecular docking studies using the monomeric BMP‐2 subunits predicted a structure which is nearly identical to that found in dimeric BMP‐2 (root mean square deviation < 1 Å) proving the suitability of geometric docking. 3D‐RP‐BMP‐2‐monomers (size 140 mm × 75 mm × 65; magnification ca. 22 × 10⁶ fold) constructed from dimeric BMP‐2 could be assembled by hand yielding a structure highly homologous to dimeric BMP‐2. Differences between the 3D‐Rapid Prototyping model of dimeric BMP‐2 and the assembled monomers arose in several gaps at the interface between the two monomers which are not visible in the dimeric structure. These gaps can be explained by the way the solvent‐accessible molecular surface is generated. During this process an exterior probe sphere is rolled over the spherical atoms of the molecule. Distances between the monomers smaller than the diameter of this sphere are bridged thus resulting in a coherent surface. We conclude that 3D‐Rapid Prototyping is in general eligible for the modelling of protein‐protein‐interaction though there are further efforts needed to increase our understanding of this process.     

Bimetal‐Organic‐Framework Derivation of Ball‐Cactus‐Like Ni‐Sn‐P@C‐CNT as Long‐Cycle Anode for Lithium Ion Battery

Metal phosphides are a new class of potential high‐capacity anodes for lithium ion batteries, but their short cycle life is the critical problem to hinder its practical application. A unique ball‐cactus‐like microsphere of carbon coated NiP₂/Ni₃Sn₄ with deep‐rooted carbon nanotubes (Ni‐Sn‐P@C‐CNT) is demonstrated in this work to solve this problem. Bimetal‐organic‐frameworks (BMOFs, Ni‐Sn‐BTC, BTC refers to 1,3,5‐benzenetricarboxylic acid) are formed by a two‐step uniform microwave‐assisted irradiation approach and used as the precursor to grow Ni‐Sn@C‐CNT, Ni‐Sn‐P@C‐CNT, yolk–shell Ni‐Sn@C, and Ni‐Sn‐P@C. The uniform carbon overlayer is formed by the decomposition of organic ligands from MOFs and small CNTs are deeply rooted in Ni‐Sn‐P@C microsphere due to the in situ catalysis effect of Ni‐Sn. Among these potential anode materials, the Ni‐Sn‐P@C‐CNT is found to be a promising anode with best electrochemical properties. It exhibits a large reversible capacity of 704 mA h g^?1 after 200 cycles at 100 mA g^?1 and excellent high‐rate cycling performance (a stable capacity of 504 mA h g^?1 retained after 800 cycles at 1 A g^?1). These good electrochemical properties are mainly ascribed to the unique 3D mesoporous structure design along with dual active components showing synergistic electrochemical activity within different voltage windows.     

Molecular Modelling of Bone Morphogenetic Protein‐2 (BMP‐2) by 3D‐Rapid Prototyping

Bone morphogenetic proteins (BMP) play a decisive role in bone development and osteogenesis. In the past they have been the subject of widespread research and clinical trials as stimulants of bone growth. Recently BMP‐2 has been chemically immobilized on implant surfaces leading to enhanced bone growth and accelerated integration in sheep. Although the 3D‐structure of BMP‐2 is known the surface topography has not been the subject of a detailed analysis. Therefore we have begun implementing the technique of 3D‐rapid prototyping as a novel method for gaining topographical information on the structure‐function relationship of proteins (Laub et al., 2001, FASEB J. 15, A543). 3D‐rapid prototyping allows the construction of accurate three‐dimensional models of proteins based on their x‐ray crystallographic data. In this way we constructed a 3D scale image of BMP‐2 of the size 140 mm × 70 mm × 50 mm corresponding to a ca. 20 × 10⁶ fold magnification (scale 1 nm = 2 cm). BMP‐2 is a twisted banana‐shaped molecule consisting of a convex and a concave face and has a horn‐like protuberance cross‐turned at 180° (long axis) at each end. In the center of the convex face there is a ca. 1 nm deep crater like pit ca. 1.8 nm in diameter. The concave face is characterized by a 6–7 nm long helical groove 0.8–1.6 nm wide and ca 0.8 nm deep, into which a left‐handed helix with a pitch of 8–9 nm and a helical radius of 0.35–0.45 nm can be fitted. The concave face of BMP‐2 therefore corresponds to an imprint (groove) of a left‐handed helix i. e. to an anti‐helix or anthelix. The possible endogenous ligands and functions of these structures are unknown. These results demonstrate that full scale 3D molecular models of proteins can lead to new perceptions in understanding the interactions between ligands and proteins by macroscopic viewing and in‐hand fitting of the molecules without the aid of a computer.