bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rapid and Electronic Identification and Quantification of Age‐Specific Circulating Exosomes via Biologically Activated Graphene Transistors
Authors: Hajian Reza , DeCastro Jonalyn , Parkinson Jonathan , Kane Alex , Camelo Andres Felipe Romero , Chou Peichi Peggy , Yang Jielin , Wong Nathan , Hernandez Ecson Daniel Obando , Goldsmith Brett , Conboy Irina , Aran Kiana 
Published: April 2021

AbstractIncreasing access to modern clinical practices concomitantly extends lifespan, ironically revealing new classes of degenerative and inflammatory diseases of later years. Here, an electronic graphene field‐effect transistor (gFET) is reported, termed EV‐chip, for label‐free, rapid identification and quantification of exosomes (EV) associated with aging through specific surface markers, CD63 and CD151. Studies suggest that blood‐derived exosomes carry specific biomolecules that can be used toward diagnostic applications of age and health. However, to observe improvements in patient outcomes, earlier detection at the point‐of‐care (POC) is required. Unfortunately, conventional techniques and other electronic‐based platforms for exosome sensing are burdensome and inept for the POC distinction of aged blood factors. It is shown that EV‐chip can quantitatively detect purified exosomes from plasma, with a limit of detection (LOD) of 2 × 104 particles mL−1 and a limit of quantification (LOQ) of 6 × 104 particles mL−1. The sensitivity and compact electronics of the EV‐chip improves upon previously published electronic biosensors, making it ideal for a physician's office or a simple biological laboratory. The sensitivity, selectivity, and portability of the EV‐chip demonstrate the potential of the biosensor as a powerful point‐of‐care diagnostic and prognostic tool for age‐related diseases.
Bioprinting of Regenerative Photosynthetic Living Materials
Authors: Balasubramanian Srikkanth , Yu Kui , Meyer Anne S. , Karana Elvin , Aubin‐Tam Marie‐Eve 
Published: April 2021

AbstractLiving materials, which are fabricated by encapsulating living biological cells within a non‐living matrix, have gained increasing attention in recent years. Their fabrication in spatially defined patterns that are mechanically robust is essential for their optimal functional performance but is difficult to achieve. Here, a bioprinting technique employing environmentally friendly chemistry to encapsulate microalgae within an alginate hydrogel matrix is reported. The bioprinted photosynthetic structures adopt pre‐designed geometries at millimeter‐scale resolution. A bacterial cellulose substrate confers exceptional advantages to this living material, including strength, toughness, flexibility, robustness, and retention of physical integrity against extreme physical distortions. The bioprinted materials possess sufficient mechanical strength to be self‐standing, and can be detached and reattached onto different surfaces. Bioprinted materials can survive stably for a period of at least 3 days without nutrients, and their life can be further extended by transferring them to a fresh source of nutrients within this timeframe. These bioprints are regenerative, that is, they can be reused and expanded to print additional living materials. The fabrication of the bioprinted living materials can be readily up‐scaled (up to ≥70 cm × 20 cm), highlighting their potential product applications including artificial leaves, photosynthetic bio‐garments, and adhesive labels.
Nanowire Based Mechanostimulating Platform for Tunable Activation of Natural Killer Cells
Authors: Bhingardive Viraj , Edri Avishay , Kossover Anna , Saux Guillaume Le , Khand Bishnu , Radinsky Olga , Iraqi Muhammed , Porgador Angel , Schvartzman Mark 
Published: April 2021

AbstractThe understanding of the activation mechanism of natural killer (NK) cells has been traditionally based on the biochemical interaction of NK cell receptors with the ligands presenting on target cells. Yet, how physical features of the NK cell environment, such as stiffness and nanoscale topography, regulate the activity of NK cells, is unknown. An artificial microenvironment is developed for NK cell stimulation based on variably elongated nanowires functionalized with activating antigens and used it as a tunable model system to study the separate and cumulative effects of elasticity and nanotopography on NK cell activation. It is found that late signaling, degranulation, and cytokine production in NK cells consistently vary with nanowire length, and it is maximized for the longest nanowires, measuring ≈20 µm in length. Intriguingly, a similar trend is observed for nanowires lacking antigens, albeit with a lower activation magnitude overall, indicating that chemical and mechanical stimuli independently determine the activation of NK cells. The demonstrated tuning of the activation of NK cells by nanoscale physical features of their environment not only provides an important insight into the regulation mechanism of these lymphocytes, but also paves the way to rationally designed nanomaterials for controlled ex vivo activation of NK cells in immunotherapy.
Squaramide‐Based Supramolecular Materials Drive HepG2 Spheroid Differentiation
Authors: Liu Tingxian , van den Berk Linda , Wondergem Joeri A. J. , Tong Ciqing , Kwakernaak Markus C. , Braak Bas ter , Heinrich Doris , van de Water Bob , Kieltyka Roxanne E. 
Published: April 2021

AbstractA major challenge in the use of HepG2 cell culture models for drug toxicity screening is their lack of maturity in 2D culture. 3D culture in Matrigel promotes the formation of spheroids that express liver‐relevant markers, yet they still lack various primary hepatocyte functions. Therefore, alternative matrices where chemical composition and materials properties are controlled to steer maturation of HepG2 spheroids remain desired. Herein, a modular approach is taken based on a fully synthetic and minimalistic supramolecular matrix based on squaramide synthons outfitted with a cell‐adhesive peptide, RGD for 3D HepG2 spheroid culture. Co‐assemblies of RGD‐functionalized squaramide‐based and native monomers resulted in soft and self‐recovering supramolecular hydrogels with a tunable RGD concentration. HepG2 spheroids are self‐assembled and grown (≈150 µm) within the supramolecular hydrogels with high cell viability and differentiation over 21 days of culture. Importantly, significantly higher mRNA and protein expression levels of phase I and II metabolic enzymes, drug transporters, and liver markers are found for the squaramide hydrogels in comparison to Matrigel. Overall, the fully synthetic squaramide hydrogels are proven to be synthetically accessible and effective for HepG2 differentiation showcasing the potential of this supramolecular matrix to rival and replace naturally‐derived materials classically used in high‐throughput toxicity screening.
Engineering Hydrogel‐Based Biomedical Photonics: Design, Fabrication, and Applications
Authors: Guimarães Carlos F. , Ahmed Rajib , Marques Alexandra P. , Reis Rui L. , Demirci Utkan 
Published: April 2021

AbstractLight guiding and manipulation in photonics have become ubiquitous in events ranging from everyday communications to complex robotics and nanomedicine. The speed and sensitivity of light–matter interactions offer unprecedented advantages in biomedical optics, data transmission, photomedicine, and detection of multi‐scale phenomena. Recently, hydrogels have emerged as a promising candidate for interfacing photonics and bioengineering by combining their light‐guiding properties with live tissue compatibility in optical, chemical, physiological, and mechanical dimensions. Herein, the latest progress over hydrogel photonics and its applications in guidance and manipulation of light is reviewed. Physics of guiding light through hydrogels and living tissues, and existing technical challenges in translating these tools into biomedical settings are discussed. A comprehensive and thorough overview of materials, fabrication protocols, and design architectures used in hydrogel photonics is provided. Finally, recent examples of applying structures such as hydrogel optical fibers, living photonic constructs, and their use as light‐driven hydrogel robots, photomedicine tools, and organ‐on‐a‐chip models are described. By providing a critical and selective evaluation of the field's status, this work sets a foundation for the next generation of hydrogel photonic research.
Protein Labeling and Crosslinking by Covalent Aptamers
Authors: Tivon Yaniv , Falcone Gianna , Deiters Alexander 
Published: April 2021

AbstractWe developed a new approach to selectively modify native proteins in their biological environment using electrophilic covalent aptamers. These aptamers are generated through introduction of a proximity‐driven electrophile at specific nucleotide sites. Using thrombin as a proof‐of‐concept, we demonstrate that covalent aptamers can selectively transfer a variety of functional handles and/or irreversibly crosslink to the target protein. This approach offers broad programmability and high target specificity. Furthermore, it addresses issues common to aptamers such as instability towards endogenous nucleases and residence times during target engagement. Covalent aptamers are new tools that enable specific protein modification and sensitive protein detection. Moreover, they provide prolonged, nuclease‐resistant enzyme inhibition.
Einsatz photolatenter Basen zur lokalen Kontrolle dynamischer Austauschreaktionen in thermisch aktivierbaren Vitrimeren
Authors: Reisinger David , Kaiser Simon , Rossegger Elisabeth , Alabiso Walter , Rieger Bernhard , Schlögl Sandra 
Published: April 2021

AbstractVitrimere sind kovalent vernetzte Polymere, die ihre Netzwerktopologie durch aktivierbaren assoziativen Bindungsaustausch neu organisieren können, wenn die Topologie‐Einfriertemperatur (Tv) überschritten wird. Trotz zahlreicher entwickelter Vitrimersysteme besteht ein gravierender Mangel an Methoden für eine kontrollierte und ortsaufgelöste Aktivierung des Bindungsaustauschs oberhalb der Tv. Hier präsentieren wir ein Konzept, das die lokale Freisetzung des effizienten Umesterungskatalysators 1,5,7‐Triazabicyclo[4.4.0]dec‐5‐en (TBD) durch UV‐induzierte Spaltung einer photolatenten Base in einem kovalent vernetzten Thiol‐Epoxid‐Polymer ermöglicht. Mittels Spannungsrelaxationsmessungen, die weit über der Tv des Netzwerks durchgeführt wurden, konnte gezeigt werden, dass nur die kontrollierte Freisetzung von TBD Umesterungen und die damit verbundene Relaxation der Netzwerkspannung ermöglicht. Zudem konnte durch lokal induzierte permanente Formänderungen im Material eine ortsaufgelöste UV‐vermittelte Photoaktivierung der vitrimeren Eigenschaften demonstriert werden.
Enantioselective Total Synthesis of the Archaeal Lipid Parallel GDGT‐0 (Isocaldarchaeol)**
Authors: Falk Isaac D. , Gál Bálint , Bhattacharya Ahanjit , Wei Jeremy H. , Welander Paula V. , Boxer Steven G. , Burns Noah Z. 
Published: April 2021

AbstractArchaeal glycerol dibiphytanyl glycerol tetraethers (GDGT) are some of the most unusual membrane lipids identified in nature. These amphiphiles are the major constituents of the membranes of numerous Archaea, some of which are extremophilic organisms. Due to their unique structures, there has been significant interest in studying both the biophysical properties and the biosynthesis of these molecules. However, these studies have thus far been hampered by limited access to chemically pure samples. Herein, we report a concise and stereoselective synthesis of the archaeal tetraether lipid parallel GDGT‐0 and the synthesis and self‐assembly of derivatives bearing different polar groups.
Investigations on performance of PEDOT:PSS/V2O5 hybrid symmetric supercapacitor with redox electrolyte
Authors: Kanth Supriya , Narayanan Padma , Betty C.A. , Rao Rekha , Kumar Sanjay 
Published: April 2021

AbstractNanocomposites of PEDOT:PSS with V2O5 nanoparticles are synthesized by simple physical mixing of the two with different weight percentages of the latter and their performance as supercapacitor electrode materials is verified. Best performance is obtained for an optimum weight percent of 16.8% of V2O5. The specific capacitance and specific energy of the composite with 16.8% V2O5 increases by more than two fold, with increase in specific power, as compared to that of pristine PEDOT:PSS device. This is attributed to increase in conductivity brought about by the presence of V2O5 nanoparticles, easier transportation and intimate contact of electrolyte ions with the nanolayers of V2O5 due to the intercalation of PEDOT:PSS between the layers, and additional redox reactions due to various oxidation states of vanadium element, besides redox electrolyte effects. This is further confirmed by the reduced ESR of the composite device as compared to that of pristine PEDOT:PSS device.
Strain rate‐dependent deformation behaviors of multi‐layer carbon fiber reinforced polymer laminates
Authors: Ma Zhichao , Li Weizhi , Yang Siguo , Huang Bin , Tong Shuai , Li Chaofan , Zhao Hongwei , Ren Luquan 
Published: April 2021

AbstractThis paper focuses on the contributions of diversities of strain rate and orientations for aggravating the diversities of micro failure behaviors on carbon fiber reinforced polymer (CFRP) laminates. A miniature horizontal type tensile tester is employed to conduct experiments with strain rate ranging from 2.6 × 10−6 s−1 to 2.6 × 10−3 s−1. The CFRP laminates are obtained based upon a thermoset toughened epoxy matrix (termed CF/Epoxy) with ply orientations of (0°/0°) and (0°/90°). Significant differences in deformation behaviors of CFRP laminates are determined through tests. The study clearly reveals the strain rate‐dependent deformation modes of CFRP laminates, involving pure fiber fracture, epoxy crack with stepped surface and interface failure with residual voids, determines the “low‐high‐low” variation tendency of Young's modulus and strength as a function of strain rate. Ply orientation‐dependent differences in deformation behaviors are also investigated via severe interfacial shearing effect. A unified model consisted of four deformation modes to is clarified to analyze the complexity of CFRP laminates failure mechanism.
Preparation of the organic–inorganic double‐shell microencapsulated aluminum hypophosphite and its improved flame retardancy and mechanical properties of epoxy resin composites
Authors: Chen Zhiquan , Li Yang , Ni Lei , Jiang Juncheng , Yu Yuan , Chen Qiang 
Published: April 2021

AbstractTo develop the functional particles with better flame‐retardant and compatibility with epoxy resin (EP) matrix, organic–inorganic double‐shell microencapsulated aluminum hypophosphite (MSiAHP) was prepared by situ polymerization. The water contact angles of MSiAHP (62.4°) is significantly larger than that of aluminum hypophosphite (34.4°), which shows that the organic shell material of MSiAHP endows excellent hydrophobicity and water resistance. With the incorporation of MSiAHP, EP/30%MSiAHP composite exhibits limiting oxygen index value of 27.3% and V‐0 rating. Furthermore, the cone calorimetry test reveals that MSiAHP reduces the peak heat release rate, total heat release and total smoke release of EP matrix by 33.3%, 24.4% and 56.6%, respectively. Besides, due to the unique organic–inorganic double‐shell structure of MSiAHP particles, EP/30%MSiAHP composite achieves greater thermal stability and higher char yields than pure EP. The investigation of the products in the gas and condensed phase demonstrates that MSiAHP is beneficial to the generation of a high‐density and compact carbon layer structure with a high graphitization degree, and delay the generation time of pyrolysis products in the gas phase, which can improve the fire safety of EP composites effectively. Furthermore, preeminent dispersion and compatibility of MSiAHP lead to EP/MSiAHP composites with excellent mechanical properties.
A Solid‐State Electrochemiluminescence Sensor Based on Novel Two‐Dimensional Ti3C2 MXene
Authors: Xing Huanhuan , Xia Hongyin , Fan Yongchao , Xue Yuan , Peng Chao , Ren Jiangtao , Li Jing , Wang Erkang 
Published: April 2021

AbstractHerein, highly conductive MXene‐Ti3C2 was employed as effective nanocarriers for anchoring electrochemiluminescence (ECL) luminophore of Ru(bpy)32+ (Ti3C2−Ru). Different from the previous work, the Ti3C2−Ru composite was achieved in several seconds due to the electrostatic interaction between positively charged Ru(bpy)32+ and negatively charged Ti3C2. A series of characterizations indicated the successful formation of Ti3C2−Ru. Then, the solid‐state ECL platform was constructed with the assistance of membrane material, Nafion. The introduction of Ti3C2 with large surface area provided a rapid strategy for capturing luminophore of Ru(bpy)32+ and endowed the solid‐state platform with good electron transfer capacity owing to the super conductivity. Based on the stable loading of Ru(bpy)32+, the as‐designed platform was successfully used for the analysis of lidocaine and the satisfied analytical results were obtained in human plasma. More importantly, the proposed approach not only enriched the application of Ti3C2 in the sensing field, but also shed light on the label‐free ECL bioanalysis.
Co(OH)2 Nanosheets Array Doped by Cu2+ Ions with Optimal Electronic Structure for Urea‐Assisted Electrolytic Hydrogen Generation
Authors: Wang Xiangyu , Zhang Wuzhengzhi , Zhang Junliang , Zhang Jing , Wu Zhengcui 
Published: April 2021

AbstractUrea electrolysis supplies a great potential in energy‐saving hydrogen generation accompanied by simultaneous urea‐containing wastewater remediation. Herein, the Co(OH)2 nanosheets arrays doped by different amount of Cu2+ ions were prepared via a one‐step solution‐phase method for urea‐assisted electrolytic hydrogen generation. The Cu integration can regulate electronic structure, activate Co active sites at low potential, and optimize the charge transfer properties and adsorption states of the catalyst. Moreover, the partially distorted cobalt surroundings caused by Cu dopant in the catalyst is conductive to favor the adsorption of urea and water molecules to the active sites. The optimal Cu6.2%‐Co(OH)2 nanosheets array exhibited superior urea oxidation reaction (UOR) and hydrogen evolution reaction (HER) performances. Assembling an overall urea electrolyzer using two Cu6.2%‐Co(OH)2 electrodes gave rise to very small voltages of 1.389 V for 10 mA cm−2 and 1.781 V for a high current density of 500 mA cm−2 with remarkable operational stability. The Cu2+ ions doping strategy can be extended to a series of Ni‐based compounds with adjustable electronic structures for boosting the activities of UOR and HER.
Proton‐Transfer Dynamics of Photoacidic Merocyanines in Aqueous Solution
Authors: Kaiser Christoph , Halbritter Thomas , Heckel Alexander , Wachtveitl Josef 
Published: April 2021

AbstractPhotoacids attract increasing scientific attention, as they are valuable tools to spatiotemporally control proton‐release reactions and pH values of solutions. We present the first time‐resolved spectroscopic study of the excited state and proton‐release dynamics of prominent merocyanine representatives. Femtosecond transient absorption measurements of a pyridine merocyanine with two distinct protonation sites revealed dissimilar proton‐release mechanisms: one site acts as a photoacid generator as its pKa value is modulated in the ground state after photoisomerization, while the other functions as an excited state photoacid which releases its proton within 1.1 ps. With a pKa drop of 8.7 units to −5.5 upon excitation, the latter phenolic site is regarded a super‐photoacid. The 6‐nitro derivative exhibits only a phenolic site with similar, yet slightly less photoacidic characteristics and both compounds transfer their proton to methanol and ethanol. In contrast, for the related 6,8‐dinitro compound an intramolecular proton transfer to the ortho‐nitro group is suggested that is involved in a rapid relaxation into the ground state.
Synthesis of Difluoroglycine Derivatives from Amines, Difluorocarbene, and CO2: Computational Design, Scope, and Applications
Authors: Hayashi Hiroki , Takano Hideaki , Katsuyama Hitomi , Harabuchi Yu , Maeda Satoshi , Mita Tsuyoshi 
Published: April 2021

AbstractA three‐component reaction (3CR) for the synthesis of difluoroglycine derivatives has been achieved by using amines, difluorocarbene (generated in situ), and the abundant, inexpensive, and nontoxic C1 source CO2. Various tert‐amines and pyridine, (iso)quinoline, imidazole, thiazole, and pyrazole derivatives were incorporated, and the corresponding products were isolated in solid form without purification by column chromatography on silica gel. Detailed reaction profiles of the 3CR were obtained from computational analysis using DFT calculations, and the results critically suggest that simple ammonia is not applicable to this reaction. In addition, as strongly supported by computational predictions, a new reagent that can generate difluorocarbene at 0 °C without any additives was discovered. Finally, radical substitution reactions of the obtained difluoroglycine derivatives under photoredox conditions, as well as a synthetic application as an N‐heterocyclic carbene ligand are shown.
Synthesis of Stannylated Aryl Imines and Amines via Aryne Insertion Reactions into Sn−N Bonds
Authors: Kran Eva , Mück‐Lichtenfeld Christian , Daniliuc Constantin G. , Studer Armido 
Published: April 2021

AbstractThe reaction of in situ generated arynes with stannylated imines to provide ortho‐stannyl‐aniline derivatives is reported. The readily prepared trimethylstannyl benzophenone imine is introduced as an efficient reagent to realize the aryne σ‐insertion reaction. The imine functionality is an established N‐protecting group and insertions proceed with good yields and good to excellent regioselectivities. The product anilines are valuable starting materials for follow‐up chemistry thanks to the rich chemistry offered by the trimethylstannyl moiety.
A Highly Efficient Conjoined‐twin Porphyrin‐based Complex for the Electrochemical Reduction of CO to Ethanol
Authors: Kour Gurpreet , Mao Xin , Du Aijun 
Published: April 2021

AbstractElectrochemical conversion of carbon monoxide, a major one‐carbon product of carbon dioxide reduction, into high‐value multi‐carbon products is one of the promising strategies to address the overall energy demands and climate change. A lot of efforts have been devoted to the exploration of highly efficient catalysts for the formation of single carbon products. However, further reduction to more reduced products is hampered by high energy barriers for C−C bond formation and low selectivity of the products. Herein, the potential of homo‐bimetallic and hetero‐bimetallic complexes of previously established expanded twin porphyrin (H4L) ligand, also known as conjoined‐twin porphyrin (CTP) ligand, towards the reduction of CO to valued commodity chemicals is systematically investigated by using density functional theory (DFT) computations. In these complexes, the presence of two metal atoms in the N4 pockets enhances the chances of coupling of two adsorbed CO molecules, thus facilitating the formation of C−C bond formation. The results reveal that both the dicobalt and cobalt nickel complex of conjoined‐twin porphyrin ligand show high activity and selectivity towards the conversion of CO to ethanol with a limiting potential of only −0.59 V and −0.61 V, respectively. The narrow band gap and shallower d band centre could be attributed to the potential cause for the enhanced activity of Co containing complexes. Moreover, these complexes displayed high thermal stability, thus acts as potential candidates for experimental exploration. Our results offer a promising alternative to traditional Cu‐based electrocatalysts for the formation of C2 products.