Modular and Versatile Spatial Functionalization of Tissue Engineering Scaffolds through Fiber‐Initiated Controlled Radical Polymerization

Native tissues are typically heterogeneous and hierarchically organized, and generating scaffolds that can mimic these properties is critical for tissue engineering applications. By uniquely combining controlled radical polymerization (CRP), end‐functionalization of polymers, and advanced electrospinning techniques, a modular and versatile approach is introduced to generate scaffolds with spatially organized functionality. Poly‐ε‐caprolactone is end functionalized with either a polymerization‐initiating group or a cell‐binding peptide motif cyclic Arg‐Gly‐Asp‐Ser (cRGDS), and are each sequentially electrospun to produce zonally discrete bilayers within a continuous fiber scaffold. The polymerization‐initiating group is then used to graft an antifouling polymer bottlebrush based on poly(ethylene glycol) from the fiber surface using CRP exclusively within one bilayer of the scaffold. The ability to include additional multifunctionality during CRP is showcased by integrating a biotinylated monomer unit into the polymerization step allowing postmodification of the scaffold with streptavidin‐coupled moieties. These combined processing techniques result in an effective bilayered and dual‐functionality scaffold with a cell‐adhesive surface and an opposing antifouling non‐cell‐adhesive surface in zonally specific regions across the thickness of the scaffold, demonstrated through fluorescent labelling and cell adhesion studies. This modular and versatile approach combines strategies to produce scaffolds with tailorable properties for many applications in tissue engineering and regenerative medicine.     

光致变色介孔二氧化硅/磷钼酸复合薄膜的制备与性能

利用蒸发诱导自组装和后植入的方法,制备出了在紫外光照下可变色的二氧化硅/磷钼酸复合薄膜.结果表明,磷钼酸粒子很好的分散并牢牢附着在有机胺改性的二氧化硅介孔薄膜的孔道中;经紫外光照后发生电荷转移,杂多阴离子被还原成杂多蓝,由无色变成蓝色,而薄膜的褪色过程则与氧气存在有关.     

Mesoporous Silica Nanoparticles: Selective Surface Functionalization for Optimal Relaxometric and Drug Loading Performances

Mesoporous silica nanoparticles (MSNs) have emerged as promising biomaterials for drug delivery and cell tracking applications, for which MRI is the medical imaging modality of choice. In this contribution, MRI contrast agents (DTPA‐Gd) and polyethylene glycol (PEG) are grafted selectively at the surface of MSNs, in order to achieve optimal relaxometric and drug loading performances. In fact, DTPA and PEG grafting procedures reported until now, have resulted in significant pore obstruction, which is detrimental to the drug delivery function of MSNs. This usually induces a dramatic decrease in surface area and pore volume, thus limiting drug loading capacity. Therefore, these molecules must be selectively grafted at the outer surface of MSNs. In this study, 3D pore network MSNs (MCM‐48‐type) are synthesized and functionalized with a straightforward and efficient grafting procedure in which DTPA and PEG are selectively grafted at the outer surface of MSNs. No pore blocking is observed, and more than 90% of surface area, pore volume and pore diameter are retained. The thus‐treated particles are colloidally stable in SBF and cell culture media, they are not cytotoxic and they have high drug loading capacity. Upon labeling with Gd, the nanoparticle suspensions have strong relaxometric properties (r₂/r₁ = 1.47, r₁ = 23.97 mM^?1 s^?1), which confers a remarkable positive contrast enhancement potential to the compound. The particles could serve as efficient drug carriers, as demonstrated with a model of daunorubicin submitted to physiological conditions. The selective nanoparticle surface grafting procedures described in the present article represent a significant advance in the design of high colloidal stability silica‐based vectors with high drug loading capacity, which could provide novel theranostic nanocompounds.     

基于可见光通信的室内光电混合网络组网关键技术

针对可见光通信在室内的应用,分析了采用可见光与无线射频构成光电混合网络的可行性,提出了一种可行的网络架构;指出了该网络架构组网中的关键技术问题,并针对网络中的光源布局、多址接入、小区切换、异构网络融合等给出了技术路线。     

锑掺杂二氧化钛的制备及其可见光催化性能

用草酸氧钛酸分解法制备了锑掺杂的二氧化钛光催化剂粉体。用XRD和TEM测定了样品的晶型、粒度等表征参数。结果表明:所制备的掺杂TiO2光催化剂为金红石型TiO2和锐钛矿型TiO2的混晶,颗粒直径在100nm左右。在可见光下,用锑掺杂量为0.2%(摩尔分数)、900℃煅烧保温0.5h后的TiO2降解6h后,甲胺磷的无机磷回收率达到96.4%。     

Designer Colloidal Layers of Disordered Plasmonic Nanoparticles for Light Extraction

Basic design rules are disclosed for broadband light‐extraction colloidal films formed with disordered ensembles of plasmonic particles. They are derived through the numerical study of a test‐bed geometry consisting of a low‐refractive index slab in air. Albeit simple, the geometry encompasses many physically effects encountered in real light‐emitting devices, including the pronounced absorption at the peak of the nanoparticles resonance spectrum, the anisotropy of the radiation diagram of nanoparticles in waveguides and unavoidable coherent multiple interferences that ruin the predictive strength of first‐order scattering models. How we can simultaneously take advantage of (1) the shape or size of the individual nanoparticles, (2) their transverse position with respect to the guiding photonic structure, (3) their concentration, and (4) the structural topology of the disorder ensemble are illustrated. Following this approach, a threefold enhancement in the extraction efficiency can be reached as compared to a film without plasmonic particles. It is also predicted that the extraction rapidly saturates and then decreases as the nanoparticle density increases, suggesting that best performance is achieved at low concentrations. Spectrally broad and directionally random far‐field radiation diagrams are additionally reported, which do not suffer from deterministic interferential behaviors observed at particular wavelengths and directionalities with periodic light‐extraction structures.     

Multifunctional Mesoporous Silica Material Used for Detection and Adsorption of Cu2+ in Aqueous Solution and Biological Applications in vitro and in vivo

An inorganic–organic silica material (SBA–P2), prepared by immobilization of the 1,8‐naphthalimide‐based receptor P2 within the channels of the mesoporous silica material SBA‐15, is characterized by transmission electron microscopy and several spectroscopic methods. SBA–P2 features a high affinity Cu²⁺‐specific fluorescence response in aqueous solution with a detection limit for Cu²⁺ of ca. 0.65 ppb (10 × 10^?9 M ) under optimized conditions. It can extract Cu²⁺ from the solution with only trace amounts remaining. Through isolating of the toxic ions within the mesopores of the silica, SBA–P2 has the potential to work as a toxicide for Cu²⁺ in living systems. The fluorogenical responses are reversible and do not vary over a broad (4.0 to 9.0) pH range suitable for application under physiological conditions. The fluorescence responses of Cu²⁺ in vitro (human breast cancer cells) and in vivo (five‐day‐old zebrafish) demonstrate the possibility of further application in biology.     

Generation of Monodisperse Mesoporous Silica Microspheres with Controllable Size and Surface Morphology in a Microfluidic Device

A one‐step in situ method, termed microfluidic diffusion‐induced self‐assembly, for the synthesis of monodisperse ordered mesoporous silica microspheres, is reported. The method combines microfluidic generation of uniform droplets and subsequent in situ rapid solvent diffusion‐induced self‐assembly within the microfluidic channel. The mesoporous silica microspheres prepared in this way reveal well‐ordered 2D hexagonal mesostructures with unprecedented corrugated surface morphology of disordered mesopores that are larger than 15 nm. It is speculated that the formation of an interfacial subphase and rapid diffusion of solvent to oil are attributed to the formation of the unique surface morphology. It is also shown that the surface morphology and the particle size of the mesoporous silica microspheres can be systematically controlled by adjusting fluidic conditions.     

近红外可见光傅里叶变换光谱仪的参考激光数字倍频方法研究

近红外可见光傅里叶变换光谱仪需要使用倍频后的参考激光千涉信号作为采样信号。由于锁相环倍频无法适用于低频的非周期信号,而传统的数字倍频方法误差又较大,因此提出了一种经过改进的基于传统数字倍频方法的算法,并对其进行了仿真和验证。实验结果表明,算法改进后,输出波形的非均匀性误差从-2%~+1.6%提高到了-0.82%~+0.4%,说明由倍频产生的非均匀性误差得到了良好改善。     

Cover Picture: Generation of Monodisperse Mesoporous Silica Microspheres with Controllable Size and Surface Morphology in a Microfluidic Device (Adv. Funct. Mater. 24/2008)

A one‐step in situ method, termed microfluidic diffusion‐induced self‐assembly, for the synthesis of monodisperse ordered mesoporous silica microspheres, is reported. The method combines microfluidic generation of uniform droplets and subsequent in situ rapid solvent diffusion‐induced self‐assembly within the microfluidic channel. The mesoporous silica microspheres prepared in this way reveal well‐ordered 2D hexagonal mesostructures with unprecedented corrugated surface morphology of disordered mesopores that are larger than 15 nm. It is speculated that the formation of an interfacial subphase and rapid diffusion of solvent to oil are attributed to the formation of the unique surface morphology. It is also shown that the surface morphology and the particle size of the mesoporous silica microspheres can be systematically controlled by adjusting fluidic conditions.     

Molten‐Salt‐Assisted Self‐Assembly (MASA)‐Synthesis of Mesoporous Metal Titanate‐Titania,Metal Sulfide‐Titania,and Metal Selenide‐Titania Thin Films

New synthetic strategies are needed for the assembly of porous metal titanates and metal chalcogenite‐titania thin films for various energy applications. Here, a new synthetic approach is introduced in which two solvents and two surfactants are used. Both surfactants are necessary to accommodate the desired amount of salt species in the hydrophilic domains of the mesophase. The process is called a molten‐salt‐assisted self‐assembly (MASA) because the salt species are in the molten phase and act as a solvent to assemble the ingredients into a mesostructure and they react with titania to form mesoporous metal titanates during the annealing step. The mesoporous metal titanate (meso‐Zn₂TiO₄ and meso‐CdTiO₃) thin films are reacted under H₂S or H₂Se gas at room temperature to yield high quality transparent mesoporous metal chalcogenides. The H₂Se reaction produces rutile and brookite titania phases together with nanocrystalline metal selenides and H₂S reaction of meso‐CdTiO₃ yields nanocrystalline anatase and CdS in the spatially confined pore walls. Two different metal salts (zinc nitrate hexahydrate and cadmium nitrate tetrahydrate) are tested to demonstrate the generality of the new assembly process. The meso‐TiO₂‐CdSe film shows photoactivity under sunlight.     

可见与近红外激光通信系统光学滤光膜的研制

在空间光通信中,光学系统起着非常重要的作用,光学薄膜技术已成为制作光学元件的关键技术。对532、808、1064、1550nm激光工作的4个波段,选择Ti3O5和SiO2作为高低折射率材料,借助于膜系设计软件,采用电子束蒸发和离子辅助沉积的方法设计并制备了激光滤光膜。镀膜后的基片在808nm处的透射率大于90%,532、1064、1550nm处的反射率均大于99%。重点解决了808nm透射区半波孔的问题,通过对基片进行清洁、减少薄膜的吸收和进行真空退火等方法提高了膜层的激光损伤阈值。经过性能测试和评估,满足系统的要求。     

Supertough Hybrid Hydrogels Consisting of a Polymer Double‐Network and Mesoporous Silica Microrods for Mechanically Stimulated On‐Demand Drug Delivery

Despite their potential in various fields of bioapplications, such as drug/cell delivery, tissue engineering, and regenerative medicine, hydrogels have often suffered from their weak mechanical properties, which are attributed to their single network of polymers. Here, supertough composite hydrogels are proposed consisting of alginate/polyacrylamide double‐network hydrogels embedded with mesoporous silica particles (SBA‐15). The supertoughness is derived from efficient energy dissipation through the multiple bondings, such as ionic crosslinking of alginate, covalent crosslinking of polyacrylamide, and van der Waals interactions and hydrogen bondings between SBA‐15 and the polymers. The superior mechanical properties of these hybrid hydrogels make it possible to maintain the hydrogel structure for a long period of time in a physiological solution. Based on their high mechanical stability, these hybrid hydrogels are demonstrated to exhibit on‐demand drug release, which is controlled by an external mechanical stimulation (both in vitro and in vivo). Moreover, different types of drugs can be separately loaded into the hydrogel network and mesopores of SBA‐15 and can be released with different speeds, suggesting that these hydrogels can also be used for multiple drug release.     

Unprecedented “All‐in‐One” Lanthanide‐Doped Mesoporous Silica Frameworks for Fluorescence/MR Imaging and Combination of NIR Light Triggered Chemo‐Photodynamic Therapy of Tumors

Designing a single multifunctional nanoparticle that can simultaneously impart both diagnostic and therapeutic functions is considered to be a long‐lasting hurdle for biomedical researchers. Conventionally, a multifunctional nanoparticle can be constructed by integrating organic dyes/magnetic nanoparticles to impart diagnostic functions and anticancer drugs/photosensitizers to achieve therapeutic outcomes. These multicomponents systems usually suffer from severe photobleaching problems and cannot be activated by near‐infrared (NIR) light. Here, it is demonstrated that all‐in‐one lanthanide‐doped mesoporous silica frameworks (EuGdOx@MSF) loaded with an anticancer drug, doxorubicin (DOX) can facilitate simultaneous bimodal magnetic resonance (MR) imaging with approximately twofold higher T₁‐MR contrast as compared to the commercial Gd(III)‐DTPA complex and fluorescence imaging with excellent photostability. Upon a very low dose (130 mW cm^?2) of NIR light (980 nm) irradiation, the EuGdOx@MSF not only can sensitize formation of singlet oxygen (¹O₂) by itself but also can phototrigger the release of the DOX payload effectively to exert combined chemo‐photodynamic therapeutic (PDT) effects and destroy solid tumors in mice completely. It is also discovered for the first time that the EuGdOx@MSF‐mediated PDT effect can suppress the level of the key drug resistant protein, i.e., p‐glycoprotein (p‐gp) and help alleviate the drug resistant problem commonly associated with many cancers.     

Breaking the Limits of Ionic Liquid‐Based Supercapacitors: Mesoporous Carbon Electrodes Functionalized with Manganese Oxide Nanosplotches for Dense,Stable, and Wide‐Temperature Energy Storage

Manganese oxide (MnO₂) nanosplotches (NSs) are deposited on N‐ and S‐doped ordered mesoporous carbon (N,S‐CMK‐3) essentially blocking microporosity. The obtained N,S‐CMK‐3/MnO₂ composite materials are assembled into ionic liquid (IL)‐based symmetric supercapacitors, which exhibit a high specific capacitance of 200 F g^?1 (0–3.5 V) at a scan rate of 2 mV s^?1, and good rate stability with 55.5% capacitance retention at a scan rate of 100 mV s^?1. The device can operate in a wide temperature range (?20 to 60 °C), and high cycling stability of N,S‐CMK‐3/MnO₂ composite electrode is demonstrated. Lower energy of ?3.56 eV can be achieved for the adsorption of 1‐ethyl‐3‐methylimidazolium⁺ (EMIM⁺) cation on the edge between MnO₂ NSs and N,S‐CMK‐3 than on the plane of MnO₂ NS (?3.04 eV), both being more preferred than the surface of pristine N,S‐CMK‐3 (?1.52 eV). This strengthening of the ion adsorption at the three‐phase boundary between N,S‐CMK‐3, MnO₂, and IL leads to enhancement of the specific capacity as compared to nondoped or MnO₂‐free reference materials. Supercapacitors based on such composite electrodes show significantly enhanced areal capacity pointing to energy storage in the mesopores rather than in the electrochemical surface layer, demonstrating a new energy storage mechanism in ILs.     

Engineering of Mesoporous Silica Coated Carbon‐Based Materials Optimized for an Ultrahigh Doxorubicin Payload and a Drug Release Activated by pH,T, and NIR‐light

Among the challenges in nanomedicine, engineering nanomaterials able to combine imaging and multitherapies is hugely needed to address issues of a personalized treatment. In that context, a novel class of drug releasing and remotely activated nanocomposites based on carbon‐based materials coated with mesoporous silica (MS) and loaded with an outstanding level of the antitumoral drug doxorubicin (DOX) is designed. First, carbon nanotubes (CNTs) and graphene sheets (called “few‐layer graphene” FLG) are processed to afford a distribution size that is more suitable for nanomedicine applications. Then, the controlled coating of MS shells having a thickness tailored with the sol–gel parameters (amount of precursor, sol–gel time) around the sliced CNTs and exfoliated FLGs is reported. Furthermore, the drug loading in such mesoporous nanocomposites is investigated and the surface modification with an aminopropyltriethoxysilane (APTS) coating leading to a controlled polysiloxane layer provides an ultrahigh payload of DOX (up to several folds the mass of the initial composites). Such new CNT‐based nanocomposites are demonstrated to release DOX at low acidic pH, high temperature (T), and remotely when they are excited by near infrared (NIR) light. Such nanoconstructs may find applications as components of innovative biomedical scaffolds for phototherapy combined with drug delivery.     

Reduction of Tungsten Oxide: A Path Towards Dual Functionality Utilization for Efficient Anode and Cathode Interfacial Layers in Organic Light‐Emitting Diodes

Here, we report on the dual functionality of tungsten oxide for application as an efficient electron and hole injection/transport layer in organic light‐emitting diodes (OLEDs). We demonstrate hybrid polymer light‐emitting diodes (Hy‐PLEDs), based on a polyfluorene copolymer, by inserting a very thin layer of a partially reduced tungsten oxide, WO_2.5, at the polymer/Al cathode interface to serve as an electron injection and transport layer. Significantly improved current densities, luminances, and luminous efficiencies were achieved, primarily as a result of improved electron injection at the interface with Al and transport to the lowest unoccupied molecular orbital (LUMO) of the polymer, with a corresponding lowering of the device driving voltage. Using a combination of optical absorption, ultraviolet spectoscopy, X‐ray photoelectron spectroscopy, and photovoltaic open circuit voltage measurements, we demonstrate that partial reduction of the WO₃ to WO_2.5 results in the appearance of new gap states just below the conduction band edge in the previously forbidden gap. The new gap states are proposed to act as a reservoir of donor electrons for enhanced injection and transport to the polymer LUMO and decrease the effective cathode workfunction. Moreover, when a thin tungsten oxide film in its fully oxidized state (WO₃) is inserted at the ITO anode/polymer interface, further improvement in device characteristics was achieved. Since both fully oxidized and partially reduced tungsten oxide layers can be deposited in the same chamber with well controlled morphology, this work paves the way for the facile fabrication of efficient and stable Hy‐OLEDs with excellent reproducibility.