Molecular Imprint for Electrochemical Detection of Streptomycin Residues Using Enzyme Signal Amplification

We have designed a new molecularly imprinted co‐polymer (MIP) for the sensitive detection of streptomycin (STR) in food using enzymes as signal amplification. The MIP was fabricated via co‐polymerization of aniline and o‐phenylenediamine on gold substrate in the presence of STR as template. The assay is based on competitive binding of free STR and glucose oxidase‐labeled STR (GOx‐STR) to the imprinters on the MIP. On addition of glucose, hydrogen peroxide is formed that is detected by differential pulse voltammetry. Under optimal conditions, the decrease of the catalytic current is proportional to the STR concentration in the range from 0.01 to 10 ng mL^?1, with a detection limit (LOD) of 7.0 pg mL^?1 STR (at 3s_B). Intra‐ and inter‐assay coefficients of variation (CVs) are<10.5 %. The system was further validated and evaluated with STR‐spiked samples including honey and milk, and the recovery was between 82 and 124.2 %.     

Fabrication of hyaluronic acid-based nanoparticles and studies on their radical scavenging activity

The purpose of this paper is to study the stability, radical scavenging activities, and bio-safety of cysteine-conjugated hyaluronic acid nanoparticles (Cys-conj-HA NPs). Additionally, the feasibility of utilizing these NPs as drug delivery systems is discussed. The structures of synthesized Cys-conj-HA polymers were analyzed using ¹H nuclear magnetic spectrum (¹H NMR) and Fourier transform infrared spectroscopy (FTIR) spectra. The stability, radical scavenging activity, and bio-safety of fabricated Cys-conj-HA NPs were investigated. Transmission electron microscopy (TEM) photograph illustrated that Cys-conj-HA NPs possessed spherical shapes with an average diameter of approximately 230 nm. Furthermore, these NPs exhibited high stability at temperatures of 4, 25, and 37°C. Notably, Cys-conj-HA NPs demonstrated significant free radical scavenging capabilities. The high cell viability observed indicated the absence of cytotoxicity from Cys-conj-HA NPs. Additionally, bio-safety studies revealed that these NPs did not induce acute toxicity in the blood and viscera of cargo-free NPs treated mice. Elisa assays indicated that there was no significant difference in the concentrations of interferon-γ (INF-γ) and tumor necrosis factor-α (TNF-α) between Cys-conj-HA NPs and normal saline (NS) treated mice (ns, p > 0.05), suggesting the absence of an inflammatory reaction caused by these NPs. Consequently, it can be concluded that Cys-conj-HA NPs are sufficiently safe to be employed as a vehicle for delivering oxidizing drugs.     

Following aptamer-ricin specific binding by single molecule recognition and force spectroscopy measurements

Single molecule recognition imaging and dynamic force spectroscopy (DFS) analysis showed strong binding affinity between an aptamer and ricin, which was comparable with antibody-ricin interaction. Molecular simulation showed a ricin binding conformation with aptamers and gave different ricin conformations immobilizing on substrates that were consistent with AFM images.     

A chemo-mechanical tweezer for single-molecular characterization of soft materials

A new atomic force microscopy (AFM)-based chemo-mechanical tweezer has been developed that can measure mechanical properties of individual macromolecules in supramolecular assembly and reveal positions of azide-containing polymers. A key feature of the new technology is the use of an AFM tip densely modified with 4-dibenzocyclooctynols (chemo-mechanical tweezer) that can react with multiple azide containing macromolecules of micelles to give triazole "clicked" compounds, which during retracting phases of AFM imaging are removed from the macromolecular assembly thereby providing a surface topographical image and positions of azide-containing polymers. The force-distance curves gave mechanical properties of removal of individual molecules from a supramolecular assembly. The new chemo-mechanical tweezer will make it possible to characterize molecular details of macromolecular assemblies thereby offering new avenues to tailor properties of such assemblies.     

用于条纹相机的计算机图象读出系统

针对条纹相机的使用要求研制了一套计算机图象读出系统,其特点是采用了积分时间可变的单次外同步CCD,保证了对瞬时结果的准确读出,从而可进行绝对测量;软件上采用WINDOWS编程,界面规范清晰易操作,数据处理充分考虑了条纹相机的使用特点,开放性的数据结构使得处理功能的扩展十分容易。     

基于金属线路板的新型大功率LED及其光电特性研究

设计、制作了基于金属线路板和板上芯片技术的大功率白光LED,对其光电特性进行了实验测量,输入电流达到800 mA,对应的输入功率3.3 W,大功率LED的输出光通量才达到饱和.输入电流达到900 mA,对应的输入功率3.8 W,大功率LED电流—电压特性仍未表现出饱和特性.实验结果表明,采用金属线路板和板上芯片技术可以得到良好的散热特性,大大提高LED的输入功率.同时还测量了光谱分布、光通量、色坐标随电流的变化情况,对其中的变化规律进行了理论分析.     

LED正向压降随温度的变化关系研究

分析了LED正向压降随温度变化的物理机理,建立了恒流驱动下正向压降随温度的变化系数测试系统对不同材料、不同发射波长的LED电压随温度变化系数进行了系统的实验研究,利用最小二乘法对实验数据进行了线性拟合,得到了不同发射波长的AlGaInP、InGaN材料LED的电压随温度变化系数,对超高亮度LED、功率型LED器件及系统的热工参数测量积累了的重要数据.     

Aptamer-LYTACs for Targeted Degradation of Extracellular and Membrane Proteins

Recently, lysosome targeting chimeras (LYTACs) have emerged as a promising technology that expands the scope of targeted protein degradation to extracellular targets. However, the preparation of chimeras by conjugation of the antibody and trivalent N-acetylgalactosamine (tri-GalNAc) is a complex and time-consuming process. The large uncertainty in number and position and the large molecular weights of the chimeras result in low internalization efficiency. To circumvent these problems, we developed the first aptamer-based LYTAC (Apt-LYTAC) to realize liver-cell-specific degradation of extracellular and membrane proteins by conjugating aptamers to tri-GalNAc. Taking advantage of the facile synthesis and low molecular weight of the aptamer, the Apt-LYTACs can efficiently and quickly degrade the extracellular protein PDGF and the membrane protein PTK7 through a lysosomal degradation pathway. We anticipate that the novel Apt-LYTACs will expand the usage of aptamers and provide a new dimension for targeted protein degradation.     

Janus Graft Block Copolymers: Design of a Polymer Architecture for Independently Tuned Nanostructures and Polymer Properties

The graft‐through synthesis of Janus graft block copolymers (GBCPs) from branched macromonomers composed of various combinations of homopolymers is presented. Self‐assembly of GBCPs resulted in ordered nanostructures with ultra‐small domain sizes down to 2.8 nm (half‐pitch). The grafted architecture introduces an additional parameter, the backbone length, which enables control over the thermomechanical properties and processability of the GBCPs independently of their self‐assembled nanostructures. The simple synthetic route to GBCPs and the possibility of using a variety of polymer combinations contribute to the universality of this technique.     

β-MnO2 microrods for the degradation of methyl orange under acid condition from aqueous solutions

Research on Chemical Intermediates - Beta-manganese dioxide (β-MnO2) microrods were hydrothermally synthesized from ammonium persulfate [(NH)4S2O8] solution using manganese sulfate (MnSO4) as...