Chiromagnetic Plasmonic Nanoassemblies with Magnetic Field Modulated Chiral Activity

Chiral plasmonic nanoassemblies, which exhibit outstanding chiroptical activity in the visible or near‐infrared region, are popular candidates in molecular sensing, polarized nanophotonics, and biomedical applications. Their optical chirality can be modulated by manipulating chemical molecule stimuli or replacing the building blocks. However, instead of irreversible chemical or material changes, real‐time control of optical activity is desired for reversible and noninvasive physical regulating methods, which is a challenging research field. Here, the directionally and reversibly switching optical chirality of magneto‐plasmonic nanoassemblies is demonstrated by the application of an external magnetic field. The gold‐magnetic nanoparticles core–satellite (Au@Fe₃O₄) nanostructures exhibit chiral activity in the UV–visible range, and the circular dichroism signal is 12 times greater under the magnetic field. Significantly, the chiral signal can be reversed by regulating the direction of the applied magnetic field. The attained magnetic field‐regulated chirality is attributed to the large contributions of the magnetic dipole moments to polarization rotation. This magnetic field‐modulated optical activity may be pivotal for photonic devices, information communication, as well as chiral metamaterials.     

DNA-Based Plasmonic Heterogeneous Nanostructures: Building,Optical Responses,and Bioapplications

The integration of multiple functional nanoparticles into a specific architecture allows the precise manipulation of light for coherent electron oscillations. Plasmonic metals-based heterogeneous nanostructures are fabricated by using DNA as templates. This comprehensive review provides an overview of the controllable synthesis and self-assembly of heterogeneous nanostructures, and analyzes the effects of structural parameters on the regulation of optical responses. The potential applications and challenges of heterogeneous nanostructures in the fields of biosensors and bioanalysis, in vivo monitoring, and phototheranostics are discussed.     

Directing Arrowhead Nanorod Dimers for MicroRNA In Situ Raman Detection in Living Cells

Directed self‐assembled nanomaterials with biological applications have attracted great interest. Here, arrowhead gold nanorod (NR) dimers with side‐by‐side and end‐to‐end motifs (known as AHSBS and AHETE dimers, respectively) presented based on selective modification of arrowhead NRs with DNA and polyethylene glycol, possessing intense surface enhanced Raman scattering (SERS) signals, are assembled for in situ intracellular microRNA detection. The arrowhead NR dimers are capable of recognizing target microRNA in a sequence‐specific manner as Raman signals significantly enhanced within dimers with both motifs. Following recognition, the dimers gradually disassemble, resulting in decreased SERS signals to achieve effective in situ Raman imaging and quantify the detection of target microRNA. The SERS intensity shows a linear relationship with intracellular target microRNA and a limit of detection of 0.011 amol ng_RNA^?1 for the AHETE dimer and 0.023 amol ng_RNA^?1 for the AHSBS dimer, respectively. The sensitivity for AHETE dimers is ≈2.1 times higher than that for AHSBS dimers, which is attributed to the small quantity of recognized molecules and stronger electrical enhancement, which causes greater SERS signals in the AHETE dimers. This approach opens up a new avenue for directed nanomaterials assembly and biological detection in living cells.     

基于Dahlin-Smith预估补偿的常压加热炉温度控制系统

针对含有纯滞后的常压加热炉温度串级控制系统,按照Dahlin算法将副回路设计为一阶加纯滞后环节,提出了带Dahlin-Smith预估补偿的前馈串级控制方案。前馈补偿可有效消除主回路中进料干扰的影响,副回路引入Dahlin-Smith预估器将纯滞后移出副环,主回路再次引入smith预估克服了副回路移到主环的纯滞后的影响。仿真表明该方案比一般的Smith加串级PID控制具有更好的鲁棒性。     

猪用生长激素(PST)脂质体制备方法和膜材的选择

本文首先对PST脂质体的制备方法进行了研究。采用薄膜法、二次乳化法、冰冻熔融法、逆相蒸发法四种方法制备PST脂质体产品，测得产品包封率分别为74．93％、76．03％、72．18％、85．03％。试验还对测定包封率的两种方法即凝胶柱分离法和鱼精蛋白凝聚法进行了比较，测得PST脂质体的包封率分别为75．26％、84．58％，PST回收率分别为90．4％和98．22％。因此确定了逆相蒸发法为本文PST脂质体的制备方法；鱼精蛋白法为试验产品包封率的测定方法。研究比较了制备PST脂质体的三种膜材。以氢化(HEPC)与非氢化(EPC)蛋黄卵磷脂制备PST脂质体的包封率分别为84．87％、86．03％。在4℃、20℃、37℃条件下贮藏HEPC—PST脂质体的渗漏率均大于EPC—PST脂质体。以大豆卵磷脂和蛋黄卵磷脂制备PST脂质体的包封率分别为71．94％、88．11％，在室温(20℃)条件下储藏，以蛋黄卵磷脂制得的PST脂质体产品稳定且颗粒均匀。结果确定非氢化蛋黄卵磷脂为本文制备PST脂质体的膜材。     

鲜切慈菇酶促褐变底物的分析确定

鲜切慈菇在贮藏过程中极易发生酶促褐变。为进一步研究其褐变机理,分析测定了慈菇对不同酚类底物的亲和性,利用薄层层析、紫外吸收光谱及高效液相色谱法鉴定鲜切慈菇酶促褐变的主要底物。结果表明,慈菇中的酚类物质主要为愈创木酚和儿茶酚,慈菇中 POD 对不同底物的结合能力依次为愈创木酚＞焦性没食子酸＞绿原酸＞L-酪氨酸＞儿茶酚,引起酶促褐变的主要底物是愈创木酚。     

猪用生长激素(PST)脂质体生物学稳定性及促生长生物活性的研究

本文着重对PST脂质体体外稳定性进行研究 ,试验表明 :PST脂质体在猪血浆中稳定性较好。对大白鼠促生长效应实验结果表明 :PST和PST脂质体对大白鼠具有促生长活性。试验组与对照组之间差异显著 (P <0 .0 5 ) ,PST脂质体具有显著的缓释作用 ,缓释期可达 7天以上     

西瓜花叶病毒三抗体夹心法与纸质免疫检测传感器检测方法的建立

利用西瓜花叶病毒2号外壳蛋白的小鼠单克隆抗体与兔多克隆抗体,建立两种针对西瓜花叶病毒2号的检测方法。运用现有的抗体建立了三抗体夹心酶联免疫吸附法(TAS-ELISA);运用碳纳米管与抗体包裹滤纸制备纸质免疫检测传感器,再基于电化学工作站建立电化学纸质免疫检测传感器检测方法。两种方法对实际样品检测限分别为0.15、0.20μg/m L,检测时间分别为3 h和30 min。根据结果分析比较,三抗体夹心法具有较高的检测灵敏度,而电化学纸质免疫传感器检测方法具有更短的检测时间。     

基于SPR技术的磺胺二甲氧嘧啶高灵敏检测

磺胺类药物的过量使用会对人体造成过敏性反应,并可能具有致癌性,而磺胺二甲氧嘧啶(Sulfadimethoxine,SDM)在食品中磺胺类药物的使用中占有很大的比例,因此基于表面等离子体共振(Surface plasmon resonance,SPR)技术建立了奶粉样品中SDM的快速、高灵敏检测方法。通过待测样品与SPR芯片表面修饰的SDM抗体分子特异性识别引起金膜表面折射率变化,进而导致SPR角的变化以实现检测。建立SPR响应信号和SDM浓度间的标准曲线,最低检测限达到0.19 ng/m L,奶粉样品添加回收率在94.0%~98.3%。和传统方法相比,SPR技术具有较高的灵敏度、准确性且操作简便,SPR传感芯片完整性好且可重复用于实际样品检测中。