Bioengineered Extracellular Membranous Nanovesicles for Efficient Small‐Interfering RNA Delivery: Versatile Platforms for Stem Cell Engineering and In Vivo Delivery

Naturally derived nanovesicles secreted from various cell types and found in body fluids can provide effective platforms for the delivery of various cargoes because of their intrinsic ability to be internalized for intercellular signal transmission and membrane recycling. In this study, the versatility of bioengineered extracellular membranous nanovesicles as potent carriers of small‐interfering RNAs (siRNAs) for stem cell engineering and in vivo delivery has been explored. Here, exosomes have been engineered, one of the cell‐derived vesicle types, to overexpress exosomal proteins fused with cell‐adhesion or cell‐penetrating peptides for enhanced intracellular gene transfer. To devise a more effective delivery system with potential for mass production, a new siRNA delivery system has also been developed by artificially inducing the outward budding of plasma membrane nanovesicles. Those nanovesicles have been engineered by overexpressing E‐cadherin to facilitate siRNA delivery to human stem cells with resistance to intracellular gene transfer. Both types of engineered nanovesicles deliver siRNAs to human stem cells for lineage specification with negligible cytotoxicity. The nanovesicles are efficient in delivering siRNA in vivo, suggesting feasibility for gene therapy. Cell‐derived, bioengineered nanovesicles used for siRNA delivery can provide functional platforms enabling effective stem cell therapeutics and in vivo gene therapy.     

Multifunctional Poly‐N‐Isopropylacrylamide/DNAzyme Microgels as Highly Efficient and Recyclable Catalysts for Biosensing

The development of highly efficient, recyclable, and multifunctional biocatalysts is of great importance for various applications, especially in biosensing. In this study, highly catalytic and recyclable DNAzyme functionalized poly‐N‐isopropylacrylamide (pNIPAM) microgels are prepared via one‐step precipitation polymerization. The pNIPAM/DNAzyme microgels exhibit highly catalytic activities in aqueous solution at room temperature, and become hydrophobic and separable from the reaction mixture at temperature higher than the lower critical solution temperature of pNIPAM, which facilitate the recyclable utilization of these catalysts. Different kinds of DNAzyme functionalized catalytic microgels can be facilely prepared via the one‐step synthesis procedure. Two typical catalytic DNA structures, the Mg²⁺‐dependent DNAzyme and the hemin‐G‐quadruplex horseradish peroxidase (HRP)‐mimicking DNAzyme, are chosen as model systems to validate the feasibility. These pNIPAM/DNAzyme microgel catalysts maintain 80% to 91% initial catalytic activity after eight times of catalysis recycling. Furthermore, the pNIPAM microgels by themselves provide additional interfaces to capturing an enzyme, glucose oxidase, which can cascade with the linked HRP mimicking DNAzymes, to form recyclable bi‐enzyme cascading system for the sensing of glucose.     

Robust Organoalkoxysilanes as Red Unconventional Fluorescent Platform

Unconventional fluorescent materials have attracted intense and continuous attention due to the facile processability, excellent biocompatibility, and high availability. However, for the lack of suitable unconventional fluorescent platform, unconventional luminophore‐based fluorescent probes have not been applied in the biological field, especially in the detection of bioactive molecules. In this work, unconventional red fluorescence is observed from a series of organoalkoxysilanes for the first time. Particularly, the unique fluorescence derived from smart Si–O bridged structures prompt the fluorescent probe design strategy. The strategy involves applying the Si–O bridge to provide desirable red unconventional fluorescence, and ratiometric detection of endogenous nitric oxide in lysosomes and in vivo. It is expected that this novel strategy will expand the applications of unconventional fluorescence to the bioimaging field, and further provide valid approach for the future evolution of unconventional fluorescent probes.     

Nanoconfined (Bio)Catalysts as Efficient Glucose‐Responsive Nanoreactors

Herein, the design, synthesis, and characterization of bifunctional hybrid nanoreactors used for concurrent one‐pot chemoenzymatic reactions are shown. In the design, the enzyme, glucose oxidase, is wrapped with a peroxidase‐mimetic catalytic polymer. Hemin, the organic catalyst, is linked to the flexible polymeric scaffold through coordination to the imidazole groups that hang out the network. This spatial arrangement, which works as a metabolic channel, is optimized for cooperative chemoenzymatic reactions in which the enzyme catalyzes first. A deep characterization of the integrated nanoreactors demonstrates that the confinement of two distinct catalytic sites in the nanospace is very effective in one‐pot reactions. Moreover, besides its role as scaffold material, the polymeric mantel protects both the biocatalyst and the chemical catalyst from degradation and inactivation in the presence of organic solvents. Furthermore, the polymeric environment of the nanoreactors can be tailored in order to trigger the assembly of those into highly active heterogeneous hybrid catalysts. Finally, the new nanoreactors are applied to the efficient degradation of organic aromatic compounds using glucose as the only fuel.     

Fluorescent Nanomaterials for the Development of Latent Fingerprints in Forensic Sciences

This review presents an overview on the application of latent fingerprint development techniques in forensic sciences. At present, traditional developing methods such as powder dusting, cyanoacrylate fuming, chemical method, and small particle reagent method, have all been gradually compromised given their emerging drawbacks such as low contrast, sensitivity, and selectivity, as well as high toxicity. Recently, much attention has been paid to the use of fluorescent nanomaterials including quantum dots (QDs) and rare earth upconversion fluorescent nanomaterials (UCNMs) due to their unique optical and chemical properties. Thus, this review lays emphasis on latent fingerprint development based on QDs and UCNMs. Compared to latent fingerprint development by traditional methods, the new methods using fluorescent nanomaterials can achieve high contrast, sensitivity, and selectivity while showing reduced toxicity. Overall, this review provides a systematic overview on such methods.     

Photopatterned Multidimensional Fluorescent Images

New methods that yield covert fluorescent images are of significant interest for applications in anti‐counterfeit technology. Printing methods that offer access to spatially controlled fluorescence intensity are needed in order to accurately reproduce unique and complex images. Herein, the use of photoreactive inks containing 9,9′‐bis(anthracene)sulfoxide (AnSO) to create complex images with spatially controlled fluorescence intensity is presented. Under UV irradiation, the SO‐bridge between anthracene units in AnSO is extruded to yield the highly luminescent molecule 9,9′‐bianthryl (BA) in quantitative yields. The irreversible formation of BA is leveraged to create multidimensional fluorescent security features that can be patterned using light and easily interpreted using the CCD camera of a mobile phone.     

Conversion‐Type MnO Nanorods as a Surprisingly Stable Anode Framework for Sodium‐Ion Batteries

The emergence of nanomaterials in the past decades has greatly advanced modern energy storage devices. Nanomaterials can offer high capacity and fast kinetics yet are prone to rapid morphological evolution and degradation. As a result, they are often hybridized with a stable framework in order to gain stability and fully utilize its advantages. However, candidates for such framework materials are rather limited, with carbon, conductive polymers, and Ti‐based oxides being the only choices; note these are all inactive or intercalation compounds. Conventionally, alloying‐/conversion‐type electrodes, which are thought to be electrochemically unstable by themselves, have never been considered as framework materials. This concept is challenged. Successful application of conversion‐type MnO nanorod as a anode framework for high‐capacity Mo₂C/MoO_x nanoparticles has been demonstrated in sodium‐ion batteries. Surprisingly, it can stably deliver 110 mAh g^?1 under extremely high rate of 8000 mA g^?1 (≈70 C) over 40 000 cycles with no capacity decay. More generally, this is considered as a proof of concept and much more alloying‐/conversion‐type materials are expected to be explored for such applications.     

2D Covalent Organic Frameworks for Biomedical Applications

Covalent organic frameworks (COFs) are an emerging class of organic crystalline polymers with well‐defined molecular geometry and tunable porosity. COFs are formed via reversible condensation of lightweight molecular building blocks, which dictate its geometry in two or three dimensions. Among COFs, 2D COFs have garnered special attention due to their unique structure composed of two‐dimensionally extended organic sheets stacked in layers generating periodic columnar π‐arrays, functional pore space, and their ease of synthesis. These unique features in combination with their low density, high crystallinity, large surface area, and biodegradability have made them an excellent candidate for a plethora of applications ranging from energy to biomedical sciences. In this article, the evolution of 2D COFs is briefly discussed in terms of different types of chemical linkages, synthetic strategies of bulk and nanoscale 2D COFs, and their tunability from a biomedical perspective. Next, the biomedical applications of 2D COFs specifically for drug delivery, phototherapy, biosensing, bioimaging, biocatalysis, and antibacterial activity are summarized. In addition, current challenges and emerging approaches in designing 2D COFs for advanced biomedical applications are discussed.     

光纤荧光探针

荧光光谱分析是一种重要的测试手段。近年来,基于光纤探针的荧光测试技术成为研究热点,这种方法具有高效、微观、实时、原位、体积小易集成等优势。简要综述荧光分析原理、光纤探针中激光发射与荧光收集的空间传导理论,以及光纤荧光探针的典型结构与制备,总结了应用于生物、环境和食品安全领域的研究状况。最后,对光纤荧光探针的发展趋势进行了展望。     

Room Temperature Fluorescent Conjugated Polymer Gums

High molecular weight poly(diphenylacetylene) [PDPA] derivatives are introduced as fluorescent, soft conjugated polymers that exist in the gum state at room temperature. The gum‐like behavior of the polymers is easily modified according to the side alkyl chain length and substitution position. Long alkyl chain‐coupled PDPA derivatives provide soft and sticky gums at room temperature. Manual kneading of gum polymers produce soft films with very smooth surfaces. The gum polymers show an endothermic transition due to the melting of long alkyl chains. The X‐ray diffraction of gum polymers reveals a new signal due to the molten aliphatic chains. The gum polymers show significant viscoelastic relaxation at the melting temperature of the alkyl side chains. The dynamic thermo‐mechanical analysis (DTMA) of gum polymers at room temperature suggest that the meta‐substituted polymer is softer and stickier than para‐polymer. Rheological analysis suggests that the meta‐polymer has less entanglement than para‐polymer. The fluorescence emission of gum polymer is quite intense in the film and solution. The gum polymer film is readily stretched to produce a uniaxually oriented film. Stretching and subsequent relaxation of elastomer‐supported gum polymer film generate buckles perpendicular to the axis of strain. The gum polymer film accommodates the large strain without cracking and delamination.     

A Versatile Photoinduced Electron Transfer‐Based Upconversion Fluorescent Biosensing Platform for the Detection of Disease Biomarkers and Nerve Agent

Upconversion nanoparticles (UCNPs) have emerged to be a new family of fluorescent probes for bioanalytical applications. In a typical design, the UCNPs act as the energy donors in a fluorescence resonance energy transfer (FRET) system, in which the target molecules mediate the energy transfer from the UCNPs to the acceptors, and their quantity information is consequently converted into the “on‐off” upconverting signals for readout. However, each UCNP contains thousands of emitting center ions and most of them are beyond the FRET critical distance, which hinders the fluorescence energy transfer efficiency, resulting in a low signal‐to‐background ratio (SBR). Herein, a new design is presented in which the energy of UCNPs is transferred to the o‐quinones on their surface via the photoinduced electron transfer (PET) mechanism. In this system, the quenching efficiency of UCNPs' fluorescence can be up to 94.73%, providing a high SBR. The performance of the PET‐based design is systematically testified, and the high‐sensitivity detection of disease biomarkers (tyrosinase and alkaline phosphatase) is demonstrated. Moreover, this UCNP‐PET platform is also capable of sensing the simulant of nerve agent sarin. This work will pave new ways to the design of UCNP‐based platforms toward bioanalytical applications.     

An Adaptable Tough Elastomer with Moisture‐Triggered Switchable Mechanical and Fluorescent Properties

Smart materials with coupled optical and mechanical responsiveness to external stimuli, as inspired by nature, are of interest for the biomimetic design of the next generation of soft machines and wearable electronics. A tough polymer that shows adaptable and switchable mechanical and fluorescent properties is designed using a fluorescent lanthanide, europium (Eu). The dynamic Eu‐iminodiacetate (IDA) coordination is incorporated to build up the physical cross‐linking network in the polymer film consisting of two interpenetrated networks. Reversible disruption and reformation of Eu‐IDA complexation endow high stiffness, toughness, and stretchability to the polymer elastomer through energy dissipation of dynamic coordination. Water that binds to Eu³⁺ ions shows an interesting impact simultaneously on the mechanical strength and fluorescent emission of the Eu‐containing polymer elastomer. The mechanical states of the polymer, along with the visually optical response through the emission color change of the polymer film, are reversibly switchable with moisture as a stimulus. The coupled response in the mechanical strength and emissive color in one single material is potentially applicable for smart materials requiring an optical readout of their mechanical properties.     

NIR‐Activated Supersensitive Drug Release Using Nanoparticles with a Flow Core

Near infrared (NIR) light‐activated supersensitive drug release via photothermal conversion is of particular interest due to its advantages in spatial and temporal control. However, such supersensitive drug release is rarely reported for polymeric nanoparticles. In this study, polymeric nanoparticles observed with flowable core can achieve NIR‐activated supersensitive drug release under the assistance of photothermal agent. It is demonstrated that only 5 s NIR irradiation (808 nm, 0.3 W cm^?2) leads to 17.8% of doxorubicin (DOX) release, while its release is almost completely stopped when the NIR laser is switched off. In contrast, the control, poly(d ,l ‐lactide) nanoparticles with rigid cores, do not exhibit such supersensitive effect. It is demonstrated that intraparticle temperature is notably increased during photothermal conversion by detecting fluorescein lifetime using a time‐correlated single photon counting (TCSPC) technique, which is the main driving force for such supersensitive drug release from hydrophobic flow core. In contrast, rigid chain of nanoparticular core hinders drug diffusion. Furthermore, such NIR light‐activated supersensitive drug release is demonstrated, which significantly enhances its anticancer efficacy, resulting in overcoming of the resistance of cancer cells against DOX treatment in vitro and in vivo. This simple and highly universal strategy provides a new approach to fabricate NIR light‐activated supersensitive drug delivery systems.     

Structure‐Invertible Nanoparticles for Triggered Co‐Delivery of Nucleic Acids and Hydrophobic Drugs for Combination Cancer Therapy

Here, a new type of structure‐invertible, redox‐responsive polymeric nanoparticle for the efficient co‐delivery of nucleic acids and hydrophobic drugs in vitro and in vivo is reported for the first time, to combat the major challenges facing combination cancer therapy. The co‐delivery vector, which is prepared by conjugating branched poly(ethylene glycol) with dendrimers of two generations (G2) through disulfide linkages, is able to complex nucleic acids and load hydrophobic drugs with high loading capacity through structure inversion. The cleavage of disulfide linkages at intracellular glutathione‐rich reduction environment significantly decreases the cytotoxicity, and promotes more efficient drug release and gene transfection in vitro and in vivo. The co‐delivery carrier also displays enhanced endosomal escape capability and improved serum stability in vitro as compared with G2, and exhibits prolonged residence time and stronger transfection activity in vivo. Most importantly, co‐delivery of doxorubicin (DOX) and B‐cell lymphoma 2 (Bcl‐2) small interfering RNA (siRNA) exerts a combinational effect against tumor growth in murine tumor models in vivo, which is much more effective than either DOX or Bcl‐2 siRNA‐based monotherapy. The structure‐invertible nanoparticles may constitute a promising stimuli‐responsive system for the efficacious co‐delivery of multiple cargoes in future clinical applications of combination cancer therapies.     

A Multifuntional Nanoplatform Based on Responsive Fluorescent Plasmonic ZnO‐Au@PEG Hybrid Nanogels

Under a rational design, combining multiple constituents into a single nano‐object will not only bridge the unique properties of individual materials to leverage research both fundamentally and practically, but will also improve conventional sensing, imaging, and therapeutic efficacies. Such a nano‐object (<100 nm) can be constructed by covalently bonding ZnO quantum dots (QDs) to nonlinear poly(ethylene glycol)‐based nanogel network chains, followed by appropriate growth of metallic Au. With the polymer gel network serving as a three‐dimensional scaffold, the fluorescence of ZnO QDs can be well protected, while metal Au still retains its surface plasmon resonance property. The ZnO QDs covalently bonded to the thermo‐responsive gel network chains can sensitively respond to temperature change of the surrounding fluids over the physiologically important range of 37–42 °C, converting the disruptions in homeostasis of local temperature into stable, robust and high‐resolution fluorescent signals. The thermoresponsive hybrid nanogels can not only enter into and light up B16F10 cells, but also regulate the release of a model anticancer drug, temozolomide, in response to either local environmental temperature change or external near‐infrared light‐induced localized hyperthermia from metal Au. The combined chemo‐photothermal therapy can significantly improve the therapeutic efficacy due to a synergistic effect.     

影响共焦荧光扫描显微镜分辨率的因素

本文分析了影响共焦荧炮扫描显微镜的各种因素－－探测器小孔直径、杂散光、物镜孔径等，并以正在研制的一台共焦荧光扫描显微镜为例；讨论了如何抑制杂散光，在设计上保证系统高分辨率实现了方法。     

固态面粉中维生素B6的荧光法直接测定

利用荧光光谱法对固体粉末面粉中痕量维生素B<,6>(VB<,6>)含量进行了研究.通过测量添加有VB<,6>的硫酸钡固体粉末样品,得到峰值波长为405 nm的荧光光谱图,其荧光强度与VB<,6>含量呈线性关系,相关系数R=0.9976.采用上述方法对面粉样品进行测量,得到峰值波长为390 nm的荧光光谱图,其荧光强度与...     

Underwater Optical Fiber Fluorescent System for Measuring Chlorophyll—a Concentration

Using optical fiber fluorescent technology, a new method for measuring alga concentration in water is presented.The system can realize on-line measurement for alga concentration using He-Ne laser as the light source.It can also effectively detect weak signals.The system with a passive sensor head has such advantages as simple structure, high sensitivity and high accuracy.It has been demonstrated that this system can be used to monitor water quality and can also be used to survey some matter.     

Phototunable Full‐Color Emission of Cellulose‐Based Dynamic Fluorescent Materials

An iridescent chameleon‐like material that can change its colors under different circumstances is always desired in color‐on‐demand applications. Herein, a strategy based on trichromacy and the dynamically tunable fluorescence resonance energy transfer (FRET) process to design and prepare these chameleon‐like fluorescent materials is proposed. A set of trichromic (red, green, and blue), solid fluorescent materials are synthesized by covalently attaching spiropyran, fluorescein, and pyrene onto cellulose chains independently. After simply mixing them together, a full range of color is realized. The chameleon‐like nature of these materials is based on the dynamic tunable FRET process between donors (green and blue) and acceptors (red) in which the energy transfer efficiency can be finely tuned by irradiation. Ultimately, the reversible and nonlinear regulation of fluorescence properties, including color and intensity, is achieved on a timescale recognizable by the naked eye. Benefited by the excellent processability inherited from the cellulose derivatives, the as‐prepared materials are feasibly transformed into different forms. Particularly, a fluorescent ink with the complicated fluorescent input–output dependence suggests more than a proof‐of‐concept; indeed, it suggests a unique method of information encryption, security printing, and dynamic anticounterfeiting.