Surface‐directed assembly of cell‐laden microgels

Cell‐laden microscale hydrogels (microgels) can be used as tissue building blocks and assembled to create 3D tissue constructs with well‐defined microarchitecture. In this article, we present a bottom‐up approach to achieve microgel assembly on a patterned surface. Driven by surface tension, the hydrophilic microgels can be assembled into well‐defined shapes on a glass surface patterned with hydrophobic and hydrophilic regions. We found that the cuboidic microgels (～100–200 µm in width) could self‐assemble into defined shapes with high fidelity to the surface patterns. The microgel assembly process was improved by increasing the hydrophilicity of the microgels and reducing the surface tension of the surrounding solution. The assembled microgels were stabilized by a secondary crosslinking step. Assembled microgels containing cells stained with different dyes were fabricated to demonstrate the application of this approach for engineering microscale tissue constructs containing multiple cell types. This bottom‐up approach enables rapid fabrication of cell‐laden microgel assemblies with pre‐defined geometrical and biological features, which is easily scalable and can be potentially used in microscale tissue engineering applications. Biotechnol. Bioeng. 2010; 105: 655–662. © 2009 Wiley Periodicals, Inc.     

Corrugation Architecture Enabled Ultraflexible Wafer‐Scale High‐Efficiency Monocrystalline Silicon Solar Cell

Advanced classes of modern application require new generation of versatile solar cells showcasing extreme mechanical resilience, large‐scale, low cost, and excellent power conversion efficiency. Conventional crystalline silicon‐based solar cells offer one of the most highly efficient power sources, but a key challenge remains to attain mechanical resilience while preserving electrical performance. A complementary metal oxide semiconductor‐based integration strategy where corrugation architecture enables ultraflexible and low‐cost solar cell modules from bulk monocrystalline large‐scale (127 × 127 cm²) silicon solar wafers with a 17% power conversion efficiency. This periodic corrugated array benefits from an interchangeable solar cell segmentation scheme which preserves the active silicon thickness of 240 µm and achieves flexibility via interdigitated back contacts. These cells can reversibly withstand high mechanical stress and can be deformed to zigzag and bifacial modules. These corrugation silicon‐based solar cells offer ultraflexibility with high stability over 1000 bending cycles including convex and concave bending to broaden the application spectrum. Finally, the smallest bending radius of curvature lower than 140 µm of the back contacts is shown that carries the solar cells segments.     

Inkjet‐Printed Micrometer‐Thick Perovskite Solar Cells with Large Columnar Grains

Transferring the high power conversion efficiencies (PCEs) of spin‐coated perovskite solar cells (PSCs) on the laboratory scale to large‐area photovoltaic modules requires a significant advance in scalable fabrication methods. Digital inkjet printing promises scalable, material, and cost‐efficient deposition of perovskite thin films on a wide range of substrates and in arbitrary shapes. In this work, high‐quality inkjet‐printed triple‐cation (methylammonium, formamidinium, and cesium) perovskite layers with exceptional thicknesses of >1 µm are demonstrated, enabling unprecedentedly high PCEs > 21% and stabilized power output efficiencies > 18% for inkjet‐printed PSCs. In‐depth characterization shows that the thick inkjet‐printed perovskite thin films deposited using the process developed herein exhibit a columnar crystal structure, free of horizontal grain boundaries, which extend over the entire thickness. A thin film thickness of around 1.5 µm is determined as optimal for PSC for this process. Up to this layer thickness X‐ray photoemission spectroscopy analysis confirms the expected stoichiometric perovskite composition at the surface and shows strong deviations and inhomogeneities for thicker thin films. The micrometer‐thick perovskite thin films exhibit remarkably long charge carrier lifetimes, highlighting their excellent optoelectronic characteristics. They are particularly promising for next‐generation inkjet‐printed perovskite solar cells, photodetectors, and X‐ray detectors.     

A novel silicon patch‐clamp chip permits high‐fidelity recording of ion channel activity from functionally defined neurons

We report on a simple and high‐yield manufacturing process for silicon planar patch‐clamp chips, which allow low capacitance and series resistance from individually identified cultured neurons. Apertures are etched in a high‐quality silicon nitride film on a silicon wafer; wells are opened on the backside of the wafer by wet etching and passivated by a thick deposited silicon dioxide film to reduce the capacitance of the chip and to facilitate the formation of a high‐impedance cell to aperture seal. The chip surface is suitable for culture of neurons over a small orifice in the substrate with minimal leak current. Collectively, these features enable high‐fidelity electrophysiological recording of transmembrane currents resulting from ion channel activity in cultured neurons. Using cultured Lymnaea neurons we demonstrate whole‐cell current recordings obtained from a voltage‐clamp stimulation protocol, and in current‐clamp mode we report action potentials stimulated by membrane depolarization steps. Despite the relatively large size of these neurons, good temporal and spatial control of cell membrane voltage was evident. To our knowledge this is the first report of recording of ion channel activity and action potentials from neurons cultured directly on a planar patch‐clamp chip. This interrogation platform has enormous potential as a novel tool to readily provide high‐information content during pharmaceutical assays to investigate in vitro models of disease, as well as neuronal physiology and synaptic plasticity. Biotechnol. Bioeng. 2010;107:593–600. © 2010 Wiley Periodicals, Inc.     

Submicron patterning of DNA oligonucleotides on silicon

The covalent attachment of DNA oligonucleotides onto crystalline silicon (100) surfaces, in patterns with submicron features, in a straightforward, two-step process is presented. UV light exposure of a hydrogen-terminated silicon (100) surface coated with alkenes functionalized with N-hydroxysuccinimide ester groups resulted in the covalent attachment of the alkene as a monolayer on the surface. Submicron-scale patterning of surfaces was achieved by illumination with an interference pattern obtained by the transmission of 248 nm excimer laser light through a phase mask. The N-hydroxysuccinimide ester surface acted as a template for the subsequent covalent attachment of aminohexyl-modified DNA oligonucleotides. Oligonucleotide patterns, with feature sizes of 500 nm, were reliably produced over large areas. The patterned surfaces were characterized with atomic force microscopy, scanning electron microscopy, epifluorescence microscopy and ellipsometry. Complementary oligonucleotides were hybridized to the surface-attached oligonucleotides with a density of 7 × 10¹² DNA oligonucleotides per square centimetre. The method will offer much potential for the creation of nano- and micro-scale DNA biosensor devices in silicon.     

Microfluidic device‐assisted etching of p‐HEMA for cell or protein patterning

The construction of biomaterials with which to limit the growth of cells or to limit the adsorption of proteins is essential for understanding biological phenomena. Here, we describe a novel method to simply and easily create thin layers of poly (2‐hydroxyethyl methacrylate) (p‐HEMA) for protein and cellular patterning via etching with ethanol and microfluidic devices. First, a cell culture surface or glass coverslip is coated with p‐HEMA. Next, a polydimethylsiloxane (PDMS) microfluidic is placed onto the p‐HEMA surface, and ethanol is aspirated through the device. The PDMS device is removed, and the p‐HEMA surface is ready for protein adsorption or cell plating. This method allows for the fabrication of 0.3 µm thin layers of p‐HEMA, which can be etched to 10 µm wide channels. Furthermore, it creates regions of differential protein adhesion, as shown by Coomassie staining and fluorescent labeling, and cell adhesion, as demonstrated by C2C12 myoblast growth. This method is simple, versatile, and allows biologists and bioengineers to manipulate regions for cell culture adhesion and growth. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 34:243–248, 2018     

Alignment of skeletal muscle myoblasts and myotubes using linear micropatterned surfaces ground with abrasives

Alignment of cells plays a significant key role in skeletal muscle tissue engineering because skeletal muscle tissue in vivo has a highly organized structure consisting of long parallel multinucleated myotubes formed through differentiation and fusion of myoblasts. In the present study, we developed an easy, simple, and low‐cost method for aligning skeletal muscle cells by using surfaces with linear microscale features fabricated by grinding. Iron blocks were ground in one direction with three kinds of abrasives (9 µm diamond suspension, #400 sandpaper, and #150 sandpaper) and then used as molds to make micropatterned polydimethylsiloxane (PDMS) substrates (type I, type II, and type III). Observation of the surface topography revealed that the PDMS substrates exhibited different degree of mean roughness (Ra), 0.03 µm for type I, 0.16 µm for type II, and 0.56 µm for type III, respectively. Murine skeletal muscle cell line C2C12 myoblasts were cultured and differentiated on the patterned PDMS substrates, and it was examined whether the alignment of C2C12 myoblasts and myotubes was possible. Although the cell growth and differentiation on the three types of patterned substrates were similar to those on the flat PDMS substrate as a control, the alignment of both C2C12 myoblasts and myotubes was obviously observed on types II and III, but not on type I or the control substrate. These results indicate that surfaces ground with abrasives will be useful for fabricating aligned skeletal muscle tissues. Biotechnol. Bioeng. 2009;103: 631–638. © 2009 Wiley Periodicals, Inc.     

Enantiospecific Analysis of 8‐Prenylnaringenin in Biological Fluids by Liquid‐Chromatography‐Electrospray Ionization Mass Spectrometry: Application to Preclinical Pharmacokinetic Investigations

8‐Prenylnaringenin (8PN) is a naturally occurring bioactive chiral prenylflavonoid found most commonly in the female flowers of hops (Humulus lupulus L.). A stereospecific method of analysis for 8PN in biological fluids is necessary to study the pharmacokinetic disposition of each enantiomer. A novel and simple liquid chromatographic‐electrospray ionization‐mass spectrometry (LC‐ESI‐MS) method was developed for the simultaneous determination of R‐ and S‐8PN in rat serum and urine. Carbamazepine was used as the internal standard (IS). Enantiomeric resolution of 8PN was achieved on a Chiralpak^® AD‐RH column with an isocratic mobile phase consisting of 2‐propanol and 10 mM ammonium formate (pH 8.5) (40:60, v/v) and a flow rate of 0.7 mL/min. Detection was achieved using negative selective ion monitoring (SIM) of 8PN at m/z 339.15 for both enantiomers and positive SIM m/z at 237.15 for the IS. The calibration curves for urine were linear over a range of 0.01–75 µg/mL and 0.05–75 µg/mL for serum with a limit of quantification of 0.05 µg/mL in serum and 0.01 µg/mL in urine. The method was successfully validated showing that it was sensitive, reproducible, and accurate for enantiospecific quantification of 8PN in biological matrices. The assay was successfully applied to a preliminary study of 8PN enantiomers in rat. Chirality 26:419–426, 2014. © 2014 Wiley Periodicals, Inc.     

Antimicrobial testing for surface‐immobilized agents with a surface‐separated live–dead staining method

Modification of a traditional live–dead staining technique based on fluorescence microscopy has yielded an improved method capable of differentiating surface‐immobilized antimicrobial agents from those agents acting via solution diffusion processes. By utilizing an inoculation chamber comprised of 50 µm polystyrene spheres as spacers between test substrate and coverslip control surfaces, three distinct bacterial cell populations can be probed by fluorescence microscopy for antimicrobial activity: (1) cells adhered to the coverslip, (2) cells adhered to the substrate, and (3) mobile cells in solution. Truly immobilized antimicrobial agents were found efficacious only at the substrate surface, while elutable agents were effective against all three populations. Glass surfaces derivatized with either quaternized poly dimethylaminoethylmethacrylate (pDMAEMA) or 3‐(trimethoxysilyl) propyldimethyloctadecyl ammonium chloride (Si‐QAC) were compared with bare glass control surfaces after contact and 4 h incubation with Staphylococcus aureus. pDMAEMA surfaces were both antimicrobial and immobilized, whereas the Si‐QAC surfaces were only observed to be antimicrobial via active diffusion. In contrast to conventional thinking, Si‐QAC surfaces showed no kill after removing all Si‐QAC elutables via rinsing procedures. The semi‐quantitative surface‐separated live–dead staining (SSLDS) technique provides mechanistic insight and represents a significant improvement relative to current microbiological test methods for evaluating immobilized, antimicrobial agents. Biotechnol. Bioeng. 2011; 108:231–236. © 2010 Wiley Periodicals, Inc.     

A 3D cell culture system: Separation distance between INS‐1 cell and endothelial cell monolayers co‐cultured in fibrin influences INS‐1 cells insulin secretion

The aim of this study was to develop an in vitro cell culture system allowing studying the effect of separation distance between monolayers of rat insulinoma cells (INS‐1) and human umbilical vein endothelial cells (HUVEC) co‐cultured in fibrin over INS‐1 cell insulin secretion. For this purpose, a three‐dimensional (3D) cell culture chamber was designed, built using micro‐fabrication techniques and validated. The co‐culture was successfully carried out and the effect on INS‐1 cell insulin secretion was investigated. After 48 and 72 h, INS‐1 cells co‐cultured with HUVEC separated by a distance of 100 µm revealed enhanced insulin secretion compared to INS‐1 cells cultured alone or co‐cultured with HUVEC monolayers separated by a distance of 200 µm. These results illustrate the importance of the separation distance between two cell niches for cell culture design and the possibility to further enhance the endocrine function of beta cells when this factor is considered. Biotechnol. Bioeng. 2013; 110: 619–627. © 2012 Wiley Periodicals, Inc.     

Scalable,Self‐Aligned Printing of Flexible Graphene Micro‐Supercapacitors

Graphene micro‐supercapacitors (MSCs) are an attractive energy storage technology for powering miniaturized portable electronics. Despite considerable advances in recent years, device fabrication typically requires conventional microfabrication techniques, limiting the translation to cost‐effective and high‐throughput production. To address this issue, we report here a self‐aligned printing process utilizing capillary action of liquid inks in microfluidic channels to realize scalable, high‐fidelity manufacturing of graphene MSCs. Microstructured ink receivers and capillary channels are imprinted on plastic substrates and filled by inkjet printing of functional materials into the receivers. The liquid inks move under capillary flow into the adjoining channels, allowing reliable patterning of electronic materials in complex structures with greatly relaxed printing tolerance. Leveraging this process with pristine graphene and ion gel inks, miniaturized all‐solid‐state graphene MSCs are demonstrated to concurrently achieve outstanding resolution (active footprint: <1 mm², minimum feature size: 20 µm) and yield (44/44 devices), while maintaining a high specific capacitance (268 µF cm^–2) and robust stability to extended cycling and bending, establishing an effective route to scale down device size while scaling up production throughput.     

A two‐electrode system‐based electrochemiluminescence detection for microfluidic capillary electrophoresis and its application in pharmaceutical analysis

A two‐electrode configuration powered by batteries was designed for a microchip capillary electrophoresis–electrochemiluminescence system. A home‐made working electrode for end‐column mode detection and wall‐jet configuration was made up of a platinum wire (0.3 mm diameter) and a quartz capillary (320 µm internal diameter). The platinum wire served as a pseudoreference electrode. The configuration of the detection power supply comprised two D‐size batteries (connected in series), a switch, and an adjustable resistor. The microchip consisted of two layers: the bottom layer was a glass sheet containing injection and separation channels; the upper layer was polydimethylsiloxane block. In order to reduce the loss of electrochemiluminescence signal, a coverslip (0.17 mm thickness) was used as the floor of the detection reservoir. The performance of the system was demonstrated by separation and detection of atropine, anisodamine and proline. The linear response for proline ranged from 5 µm to 100 µm (r = 0.9968), and the limit of detection was 1.0 µm (S/N = 3). The system was further applied to the measurement of atropine in atropine sulfate injection solutions with the limit of detection 2.3 µm . This new system is a potential tool in pharmaceutical analysis. Copyright © 2013 John Wiley & Sons, Ltd.     

Simultaneous determination of some dihydroxybenzenesulphonic acid derivatives and their degradation product and main impurity (hydroquinone) by ion‐pair liquid chromatography

A simple and sensitive high‐performance liquid chromatography method was developed and validated for the determination of calcium dobesilate (DOB) or ethamsylate (ETM) in the presence of their degradation product, hydroquinone (HQ). The analyses were carried out on Promosil C₁₈ column (4.6 mm × 250 mm, 5 µm particle size) using an ion‐pair mobile phase consisting of methanol–1.5 mm tetra‐butyl ammonium bromide in 0.06 m phosphate buffer (25 : 75, v/v) at pH 6.0 with fluorescence detection at 286/333 nm. Pindolol was used as an internal standard. The proposed method was found to be rectilinear over the concentration ranges of 0.05–0.5 µg/mL for DOB, 0.1–0.8 µg/mL for ETM and 0.005–0.1 µg/mL for HQ. The method was applied for the determination of the studied drugs in different dosage forms and biological fluids. The results of the proposed method were statistically compared with those obtained by the comparison methods revealing no significance differences in the performance of the methods regarding accuracy and precision. Moreover, applying a time‐programmed fluorescence technique was valuable for the detection of trace amounts of HQ as an impurity and allowed purity testing of ETM or DOB within the BP pharmacopeial limit (0.1%). Copyright © 2013 John Wiley & Sons, Ltd.     

Chiral 3D Open‐Framework Material Ni(D‐cam)(H2O)2 Used as GC Stationary Phase

Metal‐organic frameworks (MOFs) have been explored for analytical applications because of their outstanding properties such as high surface areas, flexibility and specific structure features, especially for chromatography application in recent years. In this work, a chiral MOF Ni(D‐cam)(H₂O)₂ with unusual integration of molecular chirality, absolute helicity, and 3‐D intrinsic chiral net was chosen as stationary phase to prepare Ni(D‐cam)(H₂O)₂‐coated open tubular columns for high‐resolution gas chromatographic (GC) separation. Two fused‐silica open tubular columns with different inner diameters and lengths, including column A (30 m × 250 µm i.d.) and column B (2 m × 75 µm i.d.), were prepared via a dynamic coating method. The chromatographic properties of the two columns were investigated using n‐dodecane as the analyte at 120 °C. The number of theoretical plates (plates/m) of the two metal–organic framework (MOF) columns was 1300 and 2750, respectively. The racemates, isomer and linear alkanes mixture were used as analytes for evaluating the separation properties of Ni(D‐cam)(H₂O)₂‐coated open tubular columns. The results showed that the columns offered good separations of isomer and linear alkanes mixture, especially racemates. Chirality 26:27–32, 2013. © 2013 Wiley Periodicals, Inc.     

Comparison of retinal nerve fiber layer thickness measurements by spectral‐domain optical coherence tomography systems using a phantom eye model

To quantify differences in nerve fiber layer thickness measurements by various spectral‐domain optical coherence tomography (SD‐OCT) systems, we developed a phantom eye model. We tested twelve SD‐OCT systems of four manufacturers. All systems combined overestimated the 49 µm thick phantom RNFL thickness on average by 18 µm. Within brands, thickness measurements differed statistically significant for one Topcon, one RTVue and one Cirrus. Between brands, thickness determined with RTVue and Topcon differed statistically significant from Cirrus and Spectralis. The maximum difference between mean thicknesses is 3.6 µm within brands and 7.7 µm between brands. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Sn‐Alloy Foil Electrode with Mechanical Prelithiation: Full‐Cell Performance up to 200 Cycles

Self‐supporting Sn foil is a promising high‐volumetric‐capacity anode for lithium ion batteries (LIBs), but it suffers from low initial Coulombic efficiency (ICE). Here, mechanical prelithiation is adopted to improve ICE, and it is found that Sn foils with coarser grains are prone to cause electrode damage. To mitigate damage and prepare thinner lithiated electrodes, 3Ag0.5Cu96.5Sn foil is used that has more refined grains (5–10 µm) instead of Sn (50–100 µm), where the abundant grain boundaries (GBs) offer more sliding systems to release stress and reduce deep fractures. Thus, the thickness of Li_x3Ag0.5Cu96.5Sn can be reduced to 50 µm, compared to 100 µm Li_xSn. When the foils contact open air, the Sn‐Li‐O(H) products are more stable than Li‐O(H), thus Li_x3Ag0.5Cu96.5Sn shows outstanding air stability. The as‐prepared 50 µm foil anode achieves stable 200 cycles in LiFePO₄//Li_x3Ag0.5Cu96.5Sn full cell (≈2.65 mAh cm^?2) and the capacity retention is 95%. Even at 5C, the capacity of Li_x3Ag0.5Cu96.5Sn is still up to ≈1.8 mAh cm^?2. The cycle life of NCM523//Li_x3Ag0.5Cu96.5Sn full cell exceeds that of NCM523//Li. Furthermore, 70 µm Li_x3Ag0.5Cu96.5Sn is used as double‐sided anode for a 3 cm × 2.8 cm pouch cell and its actual volumetric capacity density is 674 mAh cm^?3 after 50 cycles.     

Rational Design of Hierarchical “Ceramic‐in‐Polymer” and “Polymer‐in‐Ceramic” Electrolytes for Dendrite‐Free Solid‐State Batteries

Solid polymer electrolytes as one of the promising solid‐state electrolytes have received extensive attention due to their excellent flexibility. However, the issues of lithium (Li) dendrite growth still hinder their practical applications in solid‐state batteries (SSBs). Herein, composite electrolytes from “ceramic‐in‐polymer” (CIP) to “polymer‐in‐ceramic” (PIC) with different sizes of garnet particles are investigated for their effectiveness in dendrite suppression. While the CIP electrolyte with 20 vol% 200 nm Li_6.4La₃Zr_1.4Ta_0.6O₁₂ (LLZTO) particles (CIP‐200 nm) exhibits the highest ionic conductivity of 1.6 × 10^?4 S cm^?1 at 30 °C and excellent flexibility, the PIC electrolyte with 80 vol% 5 µm LLZTO (PIC‐5 µm) shows the highest tensile strength of 12.7 MPa. A sandwich‐type composite electrolyte (SCE) with hierarchical garnet particles (a PIC‐5 µm interlayer sandwiched between two CIP‐200 nm thin layers) is constructed to simultaneously achieve dendrite suppression and excellent interfacial contact with Li metal. The SCE enables highly stable Li plating/stripping cycling for over 400 h at 0.2 mA cm^?2 at 30 °C. The LiFePO₄/SCE/Li cells also demonstrate excellent cycle performance at room temperature. Fabricating sandwich‐type composite electrolytes with hierarchical filler designs can be an effective strategy to achieve dendrite‐free SSBs with high performance and high safety at room temperature.     

A novel enzymatic microreactor with Aspergillus oryzae β‐galactosidase immobilized on silicon dioxide nanosprings

The use of silicon dioxide (SiO₂) nanosprings as supports for immobilized enzymes in a continuous microreactor is described. A nanospring mat (2.2 cm² × 60 μm thick) was functionalized with γ‐aminopropyltriethoxysilane, then treated with N‐succinimidyl‐3‐(2‐pyridyldithio)‐propionate (SPDP) and dithiothreitol (DTT) to produce surface thiol (? SH) groups. SPDP‐modified β‐galactosidase from Aspergillus oryzae was immobilized on the thiolated nanosprings by reversible disulfide linkages. The enzyme‐coated nanospring mat was placed into a 175‐μm high microchannel, with the mat partially occluding the channel. The kinetics and steady‐state conversion of hydrolysis of o‐nitrophenyl β‐D ‐galactosylpyranoside at various substrate flow rates and concentrations were measured. Substantial flow was observed through the nanosprings, for which the Darcy permeability κ ≈ 3 × 10^?6 cm². A simple, one‐parameter numerical model coupling Navier‐Stokes and Darcy flow with a pseudo‐first‐order reaction was used to fit the experimental data. Simulated reactor performance was sensitive to changes in κ and the height of the nanospring mat. Permeabilities lower than 10^?8 cm² practically eliminated convective flow through the nanosprings, and substantially decreased conversion. Increasing the height of the mat increased conversion in simulations, but requires more enzymes and could cause sealing issues if grown above channel walls. Preliminary results indicate that in situ regeneration by reduction with DTT and incubation with SPDP‐modified β‐galactosidase is possible. Nanosprings provide high solvent‐accessible surface area with good permeability and mechanical stability, can be patterned into existing microdevices, and are amenable to immobilization of biomolecules. Nanosprings offer a novel and useful support for enzymatic microreactors, biosensors, and lab‐on‐chip devices. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2010     

An Ultrahigh Energy Density Quasi‐Solid‐State Zinc Ion Microbattery with Excellent Flexibility and Thermostability

The rapid development of smart wearable and integrated electronic products has urgently increased the requirement for high‐performance microbatteries. Although few lithium ion microbatteries based on organic electrolytes have been reported so far, the problems, such as undesirable energy density, poor flexibility, inflammability, volatility toxicity, and high cost restrict their practical applications in the above‐mentioned electronic products. In order to overcome these problems, a low cost quasi‐solid‐state aqueous zinc ion microbattery (ZIMB) assembled by a vanadium dioxide (B)‐multiwalled carbon nanotubes (VO₂ (B)‐MWCNTs) cathode, a zinc nanoflakes anode, and a zinc trifluoromethanesulfonate‐polyvinyl alcohol (Zn(CF₃SO₃)₂‐PVA) hydrogel electrolyte is exploited. As expected, the ZIMB exhibits excellent electrochemical performance, e.g., a high capacity of 314.7 µAh cm^?2, an ultrahigh energy density of 188.8 µWh cm^?2, and a high power density of 0.61 mW cm^?2. Furthermore, the ZIMB also shows high flexibility and excellent high temperature stability: the capacity has no obvious decay when the bending angle is up to 150° and the temperature reaches 100 °C. The ZIMB provides a way to develop next‐generation miniature energy storage devices with high performance.     

An Efficient Ultra‐Flexible Photo‐Charging System Integrating Organic Photovoltaics and Supercapacitors

Flexible and biocompatible integrated photo‐charging devices consisting of photovoltaic cells and energy storage units can provide an independent power supply for next‐generation wearable electronics or biomedical devices. However, current flexible integrated devices exhibit low total energy conversion and storage efficiency and large device thickness, hindering their applicability towards efficient and stable self‐powered systems. Here, a highly efficient and ultra‐thin photo‐charging device with a total efficiency approaching 6% and a thickness below 50 µm is reported, prepared by integrating 3‐µm‐thick organic photovoltaics on 40 µm‐thick carbon nanotube/polymer‐based supercapacitors. This flexible photo‐charging capacitor delivers much higher performance compared with previous reports by tuning the electrochemical properties of the composite electrodes, which reduce the device thickness to 1/8 while improving the total efficiency by 15%. The devices also exhibit a superior operational stability (over 96% efficiency retention after 100 charge/discharge cycles for one week) and mechanical robustness (94.66% efficiency retention after 5000 times bending at a radius of around 2 mm), providing a high‐power and long‐term operational energy source for flexible and wearable electronics.