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Typically occurring after trauma or neurosurgery treatments, dura mater defect and the ensuing cerebrospinal fluid (CSF) leakage could lead to a number of serious complications and even patient's death. Although numerous natural and synthetic dura mater substitutes have been reported, none of them have been able to fulfill the essential properties, such as anti-adhesion, leakage blockage, and pro-dura rebuilding. In this study, we devised and prepared a series of robust and biodegradable hydroxyapatite/poly(lactide-co-ε-caprolactone) (nHA/PLCL) membranes for dura repair via an electrospinning technique. In particular, PLLA/PCL (80/20) was selected for electrospinning due to its mechanical properties that most closely resembled natural dural tissue. Studies by SEM, XRD, water contact angle and in vitro degradation showed that the introduction of nHA would destroy PLCL's crystalline structure, which would further affect the mechanical properties of the nHA/PLCL membranes. When the amount of nHA added increased, so did the wettability and in vitro degradation rate, which accelerated the release of nHA. In addition, the high biocompatibility of nHA/PLCL membranes was demonstrated by in vitro cytotoxicity data. The in vivo rabbit dura repair model results showed that nHA/PLCL membranes provided a strong physical barrier to stop tissue adhesion at dura defects. Meanwhile, the nHA/PLCL and commercial group's CSF had a significantly lower number of inflammatory cells than the control groups, validating the nHA/PLCL's ability to effectively lower the risk of intracranial infection. Findings from H&E and Masson-trichrome staining verified that the nHA/PLCL electrospun membrane was more favorable for fostering dural defect repair and skull regeneration. Moreover, the relative molecular weight of PLCL declined dramatically after 3 months of implantation, according to the results of the in vivo degradation test, but it retained the fiber network structure and promoted tissue growth, demonstrating the good stability of the nHA/PLCL membranes. Collectively, the nHA/PLCL electrospun membrane presents itself as a viable option for dura repair. [ABSTRACT FROM AUTHOR]

We isolate and characterize the gold(I)–iron(0) adducts [(iPr2-bimy)Au–Fe(CO)3(PMe3)2][BArF4] and [Au–{Fe(CO)3(PMe3)2}2][BArF4] (iPr2-bimy = 1,3-diisopropylbenzimidazolin-2-ylidene, BArF4 = tetrakis(pentafluorophenyl)borate). DFT analysis reveals that the gold–iron interaction in [(iPr2-bimy)Au–Fe(CO)3(PMe3)2][BArF4] is predominantly a σ-donation from iron to gold. We further extend this class of compounds to include [(iPr2-bimy)Au–Fe(CO)3(PR3)2][BArF4] (PR3 = PPh3, PCy3, PCyPh2, PMePh2, PMe2Ph, P(4-C6H4F)3) and [(iPr2-bimy)Au–Fe(CO)4(PPh3)][BArF4] and correlate the iPr2-bimy carbenic 13C NMR signal with the relative donor strength of the iron(0) ligand. This approach allows for a fast and simple approach to gauge relative donor strength of Fe(0) donors. [ABSTRACT FROM AUTHOR]

Polyphenolic materials are a class of fascinating and versatile bioinspired materials for biointerfacial engineering. In particular, due to the presence of active chemical groups, a series of unique physicochemical properties become accessible and tunable of the as-prepared polyphenolic platforms, which could delicately regulate the cell activities via cell–material contact-dependent interactions. More interestingly, polyphenols could also affect the cell behaviors via cell–material contact-independent manner, which arise due to their intrinsically functional characteristics (e.g., antioxidant and photothermal behaviors). As such, a comprehensive understanding on the relationship between material properties and desired biomedical applications, as well as the underlying mechanism at the cellular and molecular level would provide material design principles and accelerate the lab-to-clinic translation of polyphenolic platforms. In this review, we firstly give a brief overview of cell hallmarks governed by surrounding cues, followed by the introduction of polyphenolic material engineering strategies. Subsequently, a detailed discussion on cell–polyphenols contact-dependent interfacial interaction and contact-independent interaction was also carefully provided. Lastly, their biomedical applications were elaborated. We believe that this review could provide guidances for the rational material design of multifunctional polyphenols and extend their application window. [ABSTRACT FROM AUTHOR]

Mechanistic understanding of atherosclerosis is largely hampered by the lack of a suitable in vitro human arterial model that recapitulates the arterial wall structure, and the interplay between different cell types and the surrounding extracellular matrix (ECM). This work introduces a novel microfluidic endothelial cell (EC)–smooth muscle cell (SMC) 3D co-culture platform that replicates the structural and biological aspects of the human arterial wall for modeling early atherosclerosis. Using a modified surface tension-based ECM patterning method, we established a well-defined intima–media-like structure, and identified an ECM composition (collagen I and Matrigel mixture) that retains the SMCs in a quiescent and aligned state, characteristic of a healthy artery. Endothelial stimulation with cytokines (IL-1β and TNFα) and oxidized low-density lipoprotein (oxLDL) was performed on-chip to study various early atherogenic events including endothelial inflammation (ICAM-1 expression), EC/SMC oxLDL uptake, SMC migration, and monocyte–EC adhesion. As a proof-of-concept for drug screening applications, we demonstrated the atheroprotective effects of vitamin D (1,25(OH)2D3) and metformin in mitigating cytokine-induced monocyte–EC adhesion and SMC migration. Overall, the developed arterial wall model facilitates quantitative and multi-factorial studies of EC and SMC phenotype in an atherogenic environment, and can be readily used as a platform technology to reconstitute multi-layered ECM tissue biointerfaces. [ABSTRACT FROM AUTHOR]

Compared to 0 and 1 based binary systems, organic ternary data-storage systems that record data as 0, 1 and 2 can hold much more data in a given amount of cells within a storage device. Thus, how to design a functional molecule with desired film crystallinity and definite switching mechanism is the key issue for achieving excellent ternary memory devices. However, such ternary system remained less-explored due to the lack of appropriate materials. Herein, a butyl chain-substituted molecule, namely nitrobenzene-azo-carbazole (NACB), was designed and fabricated as an ITO/NACB/Al sandwich-structured device. The vacuum-deposited NACB film shows well-defined crystalline characteristics. The following electric measurement exhibited OFF to ON1 and then to ON2 tri-current states under continuous electric field, and the switching mechanism originated from the cooperated isomerization change and charge trap double mechanisms. We hope the verified mechanism can act as a model for future ternary molecular designs. The low write and read voltage (all lower than −3 V), ternary data storage abilities indicate that the device may be used for portable, low-power consumption and super-high density memory storage. [ABSTRACT FROM AUTHOR]

Electron-rich β-diketiminate ligands, featuring amino groups at the backbone β positions ("N-nacnac" ligands) have been employed in the synthesis of a range of silylene (SiII) complexes of the type (N-nacnac)SiX (where X = H, Cl, N(SiMe3)2, P(SiMe3)2 and Si(SiMe3)3). A combination of experimental and quantum chemical approaches reveals (i) that in all cases rearrangement to give an aza-butadienyl SiIV imide featuring a contracted five-membered heterocycle is thermodynamically favourable (and experimentally viable); (ii) that the kinetic lability of systems of the type (N-nacnac)SiX varies markedly as a function of X, such that compounds of this type can be isolated under ambient conditions for X = Cl and P(SiMe3)2, but not for X = H, N(SiMe3)2 and Si(SiMe3)3; and (iii) that the ring contraction process is most facile for systems bearing strongly electron-donating and sterically less encumbered X groups, since these allow most ready access to a transition state accessed via intramolecular nucleophilic attack by the SiII centre at the β-carbon position of the N-nacnac ligand backbone. [ABSTRACT FROM AUTHOR]

β-Diketiminate ligands featuring backbone NMe2 groups have been exploited to access a series of two-coordinate cations of the type [(N-nacnac)E]+ (E = Si, Ge, Sn), whose reactivity towards N–H bonds has been investigated. While the heavier group 14 systems react via simple adduct formation, N–H oxidative addition occurs for E = Si consistent with differences in EII/EIV redox potentials. The structurally characterized Ge/Sn adducts can be viewed as models for the corresponding (transient) Si systems [(N-nacnac)Si·(NH2R)]+ (R = H, tBu) – which are potential intermediates in the formation of [(N-nacnac)Si(H)(NHR)]+via a proton-shuttling mechanism. [ABSTRACT FROM AUTHOR]

Recently, we developed fused-ring electron acceptors (FREAs) as a class of high-performance nonfullerene acceptors, which have been widely used in organic solar cells (OSCs). Here, we explore new functions of FREAs in addition to being an acceptor in a photoactive layer, and use them as an interfacial layer, which significantly improves the performance of OSCs. Compared with the conventional cathode modifying layers (CMLs) of ZnO and ZnO/polyethylenimine ethoxylated (PEIE), a novel CML of ZnO/FREA/PEIE enhances the optical mode and absorption of the device and suppresses geminate recombination via charge separation, both of which increase the short-circuit current density. In addition, FREAs passivate the surface defects of ZnO and then facilitate electron transport. The OSCs based on ZnO/FREA/PEIE exhibit a power conversion efficiency of 13.04%, higher than those based on ZnO and ZnO/PEIE (12.15% and 12.12%). [ABSTRACT FROM AUTHOR]

Polyethylenimine ethoxylated (PEIE) is a classical cathode-modifying material. Here, we report the first example of using PEIE as an anode-modifying material. We use MoO3/PEIE/Ag as a hole extraction layer to enhance the performance of inverted organic solar cells (OSCs). The introduction of an ultrathin PEIE interlayer can markedly reduce the anodic resistance of inverted devices, mostly because the ultrathin PEIE interlayer can separate MoO3 from Ag, thereby suppressing the reduction of MoO3 by gaseous Ag to lower-oxidation state Mo species which decrease the work function of MoO3 and are then detrimental to hole extraction from the photoactive layer. In addition, the PEIE interlayer can act as an optical spacer to optimize the optical absorption of inverted devices. As a result, the novel hole extraction structure of MoO3/PEIE/Ag increases device efficiency by a factor of 16% relative to conventional MoO3/Ag in inverted OSCs. [ABSTRACT FROM AUTHOR]

Hydrogels with intricate 3D networks and high hydrophilicity have qualities resembling those of biological tissues, making them ideal candidates for use as smart biomedical materials. Reactive oxygen species (ROS) responsive hydrogels are an innovative class of smart hydrogels, and are cross-linked by ROS-responsive modules through covalent interactions, coordination interactions, or supramolecular interactions. Due to the introduction of ROS response modules, this class of hydrogels exhibits a sensitive response to the oxidative stress microenvironment existing in organisms. Simultaneously, due to the modularity of the ROS-responsive structure, ROS-responsive hydrogels can be manufactured on a large scale through additive manufacturing. This review will delve into the design, fabrication, and applications of ROS-responsive hydrogels. The main goal is to clarify the chemical principles that govern the response mechanism of these hydrogels, further providing new perspectives and methods for designing responsive hydrogel materials.