光学适配体传感器检测赭曲霉毒素A的研究进展

赭曲霉毒素A(Ochratoxin A,OTA)是真菌产生的次级代谢产物,性质稳定,不易去除,人体摄入后将产生严重的健康危害。数十年来,核酸适配体不断发展,成为生物传感器的重要识别元件之一,适体传感器被广泛用于生物、医药、疾病等分析检测。本文总结了用于检测OTA的经典方法和基于核酸适配体的生物传感器方法,并主要从光学适配体传感器方面阐述了近年用于检测赭曲霉毒素A的适配体传感器,并对其进行了总结和展望。     

基于探针底物法的高效液相色谱-串联质谱法测定蚯蚓体内4种CYP同工酶活力及其应用北大核心CSCD

基于探针底物法,将蚯蚓微粒体悬浮液加入至含有混合探针底物香豆素(50μmol·L^(-1))、安非他酮(25μmol·L^(-1))、阿莫地喹(50μmol·L^(-1))、右美沙芬(5μmol·L^(-1))的孵育体系中(微粒体蛋白质量浓度需控制在32~96 mg·L^(-1)内),于37℃孵育20 min后,加入甲醇终止反应,静置10 min后过0.22μm滤膜,采用高效液相色谱-串联质谱法测定对应的代谢物7-羟基香豆素、羟基-安非他酮、N-脱乙基阿莫地喹、右啡烷的生成量。根据相应代谢物的生成量分别评价蚯蚓CYP2A6、CYP2B6、CYP2C8及CYP2D6酶活力。采用Acquity UPLC HSS T3柱作为分离柱,以不同体积比的含1 mmol·L^(-1)乙酸铵的0.05%(φ)甲酸溶液和甲醇的混合溶液作为流动相进行梯度洗脱,串联质谱中采用电喷雾离子源正离子模式和多反应监测模式检测,并用基质匹配法配制混合标准溶液系列。结果显示:7-羟基香豆素、羟基-安非他酮、N-脱乙基阿莫地喹、右啡烷的质量浓度均在2.5~50μg·L^(-1)内与其对应的峰面积呈线性关系;对空白样品进行3个浓度水平的加标回收试验,回收率为73.7%~103%,日内相对标准偏差(RSDs,n=5)为2.1%~11%,日间RSDs(n=5)为4.6%~10%。方法用于分析分别暴露于多壁碳纳米管染毒土壤(暴露组)和普通土壤(对照组)21 d后蚯蚓体内4种CYP同工酶的活力,CYP2C8酶活力明显高于CYP2A6、CYP2B6及CYP2D6,暴露组中CYP2A6及CYP2C8酶活力显著(P<0.05)高于对照组,而CYP2B6及CYP2D6酶活力与对照组的无显著性差异,因此推测可将CYP2A6及CYP2C8作为一套生物标记物,用于定性诊断土壤的多壁碳纳米管污染。     

Spatiotemporally-regulated multienzymatic polymerization endows hydrogel continuous gradient and spontaneous actuation

There are several natural materials which have evolved functional gradients,ingeniously attaining maximal efficacy from limited components.Herein,we utilized the spatiotemporal distribution of initiator acetylacetone to regulate the multienzyme polymerization and fabricate a chitosan-polymer hydrogel.The temporal priority order of acetylacetone was higher than phenolmodified chitosan by density functional theory calculation.The acetylacetone within the gelatin could gradually diffuse spatially into the chitosan hydrogel to fabricate the composite hydrogel with gradient network structure.The gradient hydrogel possessed a transferring topography from the two-dimensional pattern.A continuously decreased modulus along with acetylacetone diffusion was confirmed by atomic force microscope-based force mapping experiment.The water-retaining ability of various regions was confirmed by low-field nuclear magnetic resonance(NMR)and thermogravimetric analysis(TG)analysis,which led to the spontaneous actuation of gradient hydrogel with maximum 1821°/h curling speed and 227°curling angle.Consequently,the promising gradient hydrogels could be applied as intelligent actuators and flexible robots.     

应用2D NMR技术研究罗汉果醇及其苷的结构

从传统中药罗汉果中分离得到一系列三萜皂苷类化合物,其苷元为罗汉果醇,应用1D和2D NMR脉冲梯度场反相技术(gCOSY,gNOESY,gHMQC,gHMBC) 研究了罗汉果醇及其苷的结构,对其碳氢NMR信号进行了全归属,应用gNOESY技术研究了罗汉果醇的立体构型,并探讨了取代基对苷元质子和碳化学位移的影响.     

高通量虚拟筛选CDK2/Cyclin A2靶点抑制剂

CDK2/Cyclin A2复合蛋白的异常表达与乳腺癌、 口腔癌、 食管鳞状细胞癌的发生密切相关. CDK2/ Cyclin A2复合蛋白的活性位点不同于CDK2单体. 至今临床上尚无靶向此复合蛋白的药物分子. 针对CDK2/Cyclin A2复合蛋白, 以实验报道的10个抑制剂分子构建药效团模型, 通过药物体外药代动力学（ADME）、 Docking、 聚类分析、 毒性预测, 从DrugBank, ChEMBL和TCM@Taiwan 3个数据库约90万组数据中进行高通量虚拟筛选, 进一步进行MD模拟、 MM/PBSA结合自由能计算、 能量分解和平均非共价作用(aNCI)分析, 筛选出3个抑制效果优于阳性实验药Roscovitine的先导分子: DrugBank-2004, DrugBank-583和ChEMBL-7122. 与CDK2蛋白相比, CDK2/Cyclin A2复合蛋白结合位点空间变大, 先导分子与Lys33, Asp86, Lys129和Asp145残基之间的排斥作用有所降低, 导致结合自由能更大.     

Solvent induced enhancement of nonlinear optical response of graphdiyne

Flat and crystalline materials with exceptional nonlinear optical(NLO) properties are highly desirable for their potential applications in integrated NLO photonic devices.Graphdiyne(GD),a new twodimensional(2 D) carbon allotrope,has recently evoked burgeoning research attention by virtue of its tunable bandgap along with a high carrier mobility and extended π-conjugation compared with most conventional optical materials.Here,we experimentally probe the third-order nonlinear optical response of GD dispersed in several common solvents(alcohols) using a femtosecond Z-scan technique.The measured nonlinear optical refractive index is in the order of ~10^-8 cm²/W,which is approximately one order of magnitude higher than that of most 2 D materials.In particular,we find that different NLO responses can be observed from GD when dispersed in different solvents,with the strongest NLO response when dispersed in 1-propanol.It is proposed that some intrinsic properties of the solvents,such as the polarity and viscosity,could influence the NLO response of GD materials.Our experimental results confirm the assumptions on the NLO behavior in GD and demonstrate its great potential for future generations of Kerr-effect-based NLO materials and devices.     

520nm泵浦780nm+1560nm双共振光学参量振荡器

我们在实验中演示了520nm单频绿光泵浦的基于周期极化磷酸钛氧钾(PPKTP)晶体的780nm+1560nm双共振光参量振荡器,高效制备780nm+1 560nm连续可调谐双色下转换光场。该参量振荡器可输出93.3 mW的1 560nm单频激光和44.6mW的780nm单频激光。通过改变PPKTP晶体的温度所得到的波长粗调范围为:信号光1 529.81nm~1 573.83nm(~44nm),闲置光788.26nm~777.20nm(~11nm);通过连续调谐520nm泵浦激光频率初步得到的闲置光在780.24nm(铷原子D2线)处频率连续调谐范围约1.6GHz。     

PW_(11)O_(39)Co(Ⅱ)(H_2O)~(5-)的均相及异相体系可见光催化性能研究

以模型污染物罗丹明B(RhB)的光降解为探针,评估了Keggin型钴取代杂多阴离子PW11O39Co髤(H2O)5-(PW11Co)及其异相体系PW11Co/D301R的可见光催化活性,提出了光催化反应的机理,同时考察了催化剂用量、溶液酸度以及溶液中PW11Co和RhB的相互作用对RhB可见光催化降解速率的影响。实验结果表明,PW11Co均相体系及其异相体系PW11Co/D301R对RhB的可见光降解均有较高的光催化活性,但PW11Co/D301R的光催化活性更高。导致RhB降解的主要是羟基自由基。与PW11Co均相体系相比,在PW11Co/D301R异相体系中由于PW11Co与RhB的配位作用大为减弱,同时D301R对RhB具有富集作用,因而大大提高了RhB的光催化降解速率。     

Gold nanoparticles-enhanced bisphenol A electrochemical biosensor based on tyrosinase immobilized onto self-assembled monolayers-modified gold electrode

A novel electrochemical sensor based on the immobilization of tyrosinase(tyr) onto gold nanoparticles(nano-Au) and thioctic acid amide(T-NH2) self-assembled monolayers(SAMs)-modified gold electrode has been developed for the determination of bisphenol A(BPA).It was found that the nano-Au could significantly enhance the electrochemical response of tyr/nano-Au/T-NH2/Au electrode to BPA,and the enhancement effect of nano-Au on the current response was also related to the enzyme.The results indicated that the biosensor could be used as a detector for BPA determination with a linear range from3.99 ×10-7mol/L to 2.34 ×10-4mol/L and a detection limit of 1.33×10-7mol/L.In addition,this biosensor showed good reproducibility.     

Electrochemical sensor based on f-SWCNT and carboxylic group functionalized PEDOT for the sensitive determination of bisphenol A

A simple,sensitive,and reliable method for the voltammetric determination of bisphenol A(BPA) by using carboxylic group functionalized single-walled carbon nanotubes(f-SWCNT)/carboxylic-functionalized poly(3,4-ethylenedioxythiophene)(PC4) complex modified glassy carbon electrode(GCE) has been successfully developed.The electrochemical behavior of BPA at the surface of the modified electrode is investigated by electrochemical techniques.The cyclic voltammetry results show that the as-prepared electrode exhibits strong catalytic activity toward the oxidation of BPA with a well-defined anodic peak at 0.623 V in PBS(0.1 mol/L,pH 7.0).The surface morphology of the 3D network of composite film is beneficial for the adsorption of analytes.Under the optimized conditions,the oxidation peak current is proportional to BPA concentration in the range between 0.099 and 5.794 μmol/L(R~2 = 0.9989),with a limit of detection of 0.032 μmol/L(S/N = 3).The enhanced performance of the sensor can be attributed to the excellent electrocatalytic property of/-SWCNT and the extraordinary conductivity of PC4.Furthermore,the proposed modified electrode displays high stability and good reproducibility.The good result on the voltammetric determination of BPA also indicates that the asfabricated modified electrode will be a good candidate for the electrochemical determination and analysis of BPA.