Responsive Exosome Nano‐bioconjugates for Synergistic Cancer Therapy

Exosomes hold great potential in therapeutic development. However, native exosomes usually induce insufficient effects in vivo and simply act as drug delivery vehicles. Herein, we synthesize responsive exosome nano‐bioconjugates for cancer therapy. Azide‐modified exosomes derived from M1 macrophages are conjugated with dibenzocyclooctyne‐modified antibodies of CD47 and SIRPα (aCD47 and aSIRPα) through pH‐sensitive linkers. After systemic administration, the nano‐bioconjugates can actively target tumors through the specific recognition between aCD47 and CD47 on the tumor cell surface. In the acidic tumor microenvironment, the benzoic‐imine bonds of the nano‐bioconjugates are cleaved to release aSIRPα and aCD47 that can, respectively, block SIRPα on macrophages and CD47, leading to abolished “don't eat me” signaling and improved phagocytosis of macrophages. Meanwhile, the native M1 exosomes effectively reprogram the macrophages from pro‐tumoral M2 to anti‐tumoral M1.     

High-refractive index acrylate polymers for applications in nanoimprint lithography

The development of polymeric optical materials with a higher refractive index,transparency in the visible spectrum region and easier processability is increasingly desirable for advanced optical applications such as microlenses,image sensors,and organic light-emitting diodes.Most acrylates have a low refractive index(around 1.50)which does not meet the high perfo rmance requirements of advanced optical materials.In this research,three novel acrylates were synthesized via a facile one-step approach and used to fabricate optical transparent polymers.All of the polymers reveal good optical properties including high transparency(≥90%)in the visible spectrum region and high refractive index values(1.6363)at 550 nm.Moreover,nanostructures of these acrylate polymers with various feature sizes including nanogratings and photonic crystals were successfully fabricated using nanoimprint lithography.These results indicate that these acrylates can be used in a wide range of optical and optoelectronic devices where nanopatterned films with high refractive index and transparency are required.     

Three‐Pronged Attack by Homologous Far‐red/NIR AIEgens to Achieve 1+1+1>3 Synergistic Enhanced Photodynamic Therapy

Photodynamic therapy (PDT) has long been shown to be a powerful therapeutic modality for cancer. However, PDT is undiversified and has become stereotyped in recent years. Exploration of distinctive PDT methods is thus highly in demand but remains a severe challenge. Herein, an unprecedented 1+1+1>3 synergistic strategy is proposed and validated for the first time. Three homologous luminogens with aggregation‐induced emission (AIE) characteristics were rationally designed based on a simple backbone. Through slight structural tuning, these far‐red/near‐infrared AIE luminogens are capable of specifically anchoring to mitochondria, cell membrane, and lysosome, and effectively generating reactive oxygen species (ROS). Notably, biological studies demonstrated combined usage of three AIE photosensitizers gives multiple ROS sources simultaneously derived from several organelles, which gives superior therapeutic effect than that from a single organelle at the same photosensitizers concentration. This strategy is conceptually and operationally simple, providing an innovative approach and renewed awareness of improving therapeutic effect through three‐pronged PDT.     

Recent advances of ambient ionization mass spectrometry imaging in clinical research

The structural information and spatial distribution of molecules in biological tissues are closely related to the potential molecular mechanisms of disease origin, transfer, and classification. Ambient ionization mass spectrometry imaging is an effective tool that provides molecular images while describing in situ information of biomolecules in complex samples, in which ionization occurs at atmospheric pressure with the samples being analyzed in the native state. Ambient ionization mass spectrometry imaging can directly analyze tissue samples at a fairly high resolution to obtain molecules in situ information on the tissue surface to identify pathological features associated with a disease, resulting in the wide applications in pharmacy, food science, botanical research, and especially clinical research. Herein, novel ambient ionization techniques, such as techniques based on spray and solid‐liquid extraction, techniques based on plasma desorption, techniques based on laser desorption ablation, and techniques based on acoustic desorption were introduced, and the data processing of ambient ionization mass spectrometry imaging was briefly reviewed. Besides, we also highlight recent applications of this imaging technology in clinical researches and discuss the challenges in this imaging technology and the perspectives on the future of the clinical research.     

Enhanced in vitro biocompatibility of ultrafine-grained biomedical NiTi alloy with microporous surface

Bulk ultrafine-grained Ni_50.8Ti_49.2 alloy (UFG-NiTi) was successfully fabricated by equal-channel angular pressing (ECAP) technique in the present study, and to further improve its surface biocompatibility, surface modification techniques including sandblasting, acid etching and alkali treatment were employed to produce either irregularly roughened surface or microporous surface or hierarchical porous surface with bioactivity. The effect of the above surface treatments on the surface roughness, wettability, corrosion behavior, ion release, apatite forming ability and cytocompatibility of UFG-NiTi alloy were systematically investigated with the coarse-grained NiTi alloy as control. The pitting corrosion potential (E_pit) was increased from 393 mV (SCE) to 704 mV (SCE) with sandblasting and further increased to 1539 mV (SCE) with following acid etching in HF/HNO₃ solution. All the above surface treatment increased the apatite forming ability of UFG-NiTi in varying degrees when soaked them in simulated body fluid (SBF). Meanwhile, both sandblasting and acid etching could promote the cytocompatibility for osteoblasts: sandblasting enhanced cell attachment and acid etching increased cell proliferation. The different corrosion behavior, apatite forming ability and cellular response of UFG-NiTi after different surface modifications are attributed to the topography and wettability of the resulting surface oxide layer.     

CuI/Al双层电极的有机场效应晶体管

制备了CuI/Al为源极和漏电极的并五苯基场效应晶体管.相对于纯金属(Al, Au)电极的晶体管,所研制的晶体管的迁移率、阈值电压VT、开关电流比I_on/I_off等参数都有明显改善.研究发现,在Al电极与并五苯半导体之间引入CuI作为空穴注入层,能够明显降低Al电极与并五苯之间的空穴注入势垒.紫外-可见光谱和X射线光电子能谱数据表明,这种空穴注入势垒的降低源自并五苯和Al向CuI的电子转移. 关键词： 有机场效应晶体管 CuI/Al双层源漏电极 电子转移     

陕南茶叶稀土元素产地特征研究

为了掌握陕南茶叶中稀土元素含量和分布状况,并利用稀土元素对茶叶产地进行判别,采用ICP-MS法对陕南地区44个茶叶样品中16种稀土元素进行了测定。结果表明:茶叶中不同稀土元素含量差异较大,其中La,Ce,Nd含量较高,平均含量分别为124.81,172.13,87.20μg·kg-1;茶叶样品中稀土氧化物含量范围为200.32~1558.35μg·kg-1,总体上呈东高西低趋势,且均低于国家规定限量;茶叶中稀土元素随地域变化表现出不同分布特征,但具有相似的丰度模式;利用主成分分析将茶叶稀土元素归结为轻稀土组和重稀土组,间接地证明轻稀土元素和重稀土元素在从土壤到茶叶迁移过程中仍存在着差异;聚类分析结果表明,稀土元素可作为陕南茶叶产地判别的重要指标。     

Oligotriarylamines with a Pyrene Core: A Multicenter Strategy for Enhancing Radical Cation and Dication Stability and Tuning Spin Distribution

Monoamine 1 , diamines 2 – 4 , triamine 5 , and tetraamine 6 have been synthesized by substituting dianisylamino groups at the 1‐, 3‐, 6‐, and/or 8‐positions of pyrene. Diamines 2 – 4 differ in the positions of the amine substituents. No pyrene–pyrene interactions are evident in the single‐crystal packing of 3 , 4 , and 6 . With increasing numbers of amine substituents, the first oxidation potential decreases progressively from the mono‐ to the tetraamine. These compounds show intense charge‐transfer (CT) emission in CH₂Cl₂ at around 530 nm with quantum yields of 48–68 %. Upon stepwise oxidation by electrolysis or chemical oxidation, these compounds were transformed into radical cations 1 ^?+– 6 ^?+ and dications 2 ²⁺– 6 ²⁺, which feature strong visible and near‐infrared absorptions. Time‐dependent density functional theory studies suggested the presence of localized transitions from the pyrene radical cation and aminium radical cation, intervalence CT, and CT between the pyrene and amine moieties. Spectroscopic studies indicated that these radical cations and dications have good stability. Triamine 5 and tetraamine 6 formed efficient CT complexes with tetracyanoquinodimethane in solution. The results of EPR spectroscopy and density functional theory calculations suggested that the dications 2 ²⁺– 4 ²⁺ have a triplet ground state, whereas 5 ²⁺ and 6 ²⁺ have a singlet ground state. The dication of 1,3‐disubstituted diamine 4 exhibits a strong EPR signal.     

Copper‐Catalyzed One‐Pot Denitrogenative–Dehydrogenative–Decarboxylative Coupling of β‐Ketoacids with Trifluorodiazoethane: Facile Access to Trifluoromethylated Aldol Products

A novel copper‐catalyzed one‐pot cross‐coupling of β‐ketoacids with in situ generated trifluorodiazoethane has been developed. This reaction provides a direct and efficient method, in which one C?C bond and one C?O bond were formed in a carbenoid center with concomitant denitrogenation–dehydrogenation–decarboxylation, to afford trifluoromethylated aldol products. In several preliminary experiments, good to high enantioselectivities were also obtained.     

Direct electrosynthesis and characterization of a new soluble polyfluorene derivative containing carboxyl group in boron trifluoride diethyl etherate

High-quality poly(fluorene-9-acetic acid) (PFAA), a new soluble polyfluorene derivative, was synthesized electrochemically by direct anodic oxidation of fluorene-9-acetic acid (FAA) in boron trifluoride diethyl etherate (BFEE) containing a certain amount of trifluoroacetic acid (TFA). This electrolyte enables facile anodic oxidation of FAA monomer at lower potential (1.05 V vs. SCE). PFAA films with conductivity of 0.53 S cm⁻¹ obtained from this medium showed better redox activity and thermal stability in relation to unsoluble poly(fluorene-9-carboxylic acid). Fluorescent spectral studies indicate that PFAA film with high fluorescence quantum yields and photochemical stability is a good blue-light emitter. The structure and morphology of the polymer were studied by UV–vis, FT-IR, ¹H NMR spectra and scanning electron microscopy, respectively.