A highly sensitive fluorescent probe RN-NA reveals peroxynitrite as a novel biomarker for primary open angle glaucoma

AIM:To directly quantify peroxynitrite(ONOO-)using a highly sensitive fluorescence resonance energy transfer probe RN-NA,investigate the association between ONOOand primary open angle glaucoma(POAG),and clarify whether RN-NA could be used as a potential tool for POAG diagnosis.METHODS:Plasma and aqueous humor(AH)samples were collected from POAG patients(n=100,age:59.70±6.87y)and age-related cataract(ARC)patients(n=100,age:61.15±4.60y)admitted to our hospital.Next,RN-NA was used to detect ONOO-in plasma and AH samples,and the relationship between ONOO-level and POAG was analyzed using binary logistic regression.Besides,Pearson correlation analysis was applied to characterize the correlation of the levels of ONOO-with the patients’age,intraocular pressure(IOP),and mean deviation of visual field testing.The ONOO-scavenger MnTMPyP was employed to treat the 3-morpholinosyndnomine(SIN-1)-induced ocular hypertension in mice(n=7,6-8wk).Finally,the IOP and ONOO-in both eyes were measured 30min after the last drug treatment.RESULTS:ONOO-levels of AH and plasma were significantly higher in the POAG group than in the ARC group(P<0.01).Additionally,ONOO-levels were closely correlated with POAG in a binary logistic regression analysis[odds ratio(OR)=1.008,95%confidence interval(CI):1.002-1.013,P<0.01 for AH;OR=1.004,95%CI:1.002-1.006,P<0.001 for plasma].Pearson correlation analysis showed that ONOO-levels in AH or plasma were positively associated with visual field defects(R=0.51,P<0.01 for AH;R=0.45,P<0.001 for plasma),and ONOO-levels in plasma and AH were correlated in the POAG group(R=0.69,P<0.001).However,administering MnTMPyP to mouse eyes reversed the elevated IOP caused by SIN-1(P<0.05).CONCLUSION:ONOO-levels in AH and plasma,detected by RN-NA,are significantly related to POAG and positively correlated with visual field defects in POAG patients.Hence,ONOO-is a potential biomarker of POAG,especially advanced POAG.Besides,anti-nitration compounds may be novel ocular hypotensive agents based on the animal study.

A ratiometric fluorescent probe for hypoxanthine detection in aquatic products based on the enzyme mimics and fluorescence of cobalt-doped carbon nitride

A ratiometric fluorescent probe for hypoxanthine(Hx)detection was established based on the mimic enzyme and fluorescence characteristics of cobalt-doped graphite-phase carbon nitride(Co doped g-C_(3)N_(4)).In addition to emitting strong fluorescence,the peroxidase activity of Co doped g-C_(3)N_(4)can catalyze the reaction of O-phenylenediamine and H_(2)O_(2)to produce diallyl phthalate which can emit yellow fluorescence at 570 nm.Through the decomposition of Hx by xanthine oxidase,Hx can be indirectly detected by the generating hydrogen peroxide based on the measurement of fluorescent ratio I(F_(570)/F_(370)).The linear range was 1.7-272.2 mg/kg(R^(2)=0.997),and the detection limit was 1.52 mg/kg(3σ/K,n=9).The established method was applied to Hx detection in bass,grass carp,and shrimp,and the data were verified by HPLC.The result shows that the established probe is sensitive,accurate,and reliable,and can be used for Hx detection in aquatic products.

一种新型Al^(3+)荧光探针的合成及与DNA的相互作用

以2-羟基-1-萘甲醛、邻氨基苯甲醛为原料,设计合成了一种新型Schiff碱Al^(3+)荧光探针S,并通过1HNMR、^(13)CNMR、ESI-MS、IR对探针S进行结构表征。光谱实验结果表明,探针S在DMSO∶H_(2)O=4∶1(V/V)体系中,对Al^(3+)有良好的荧光和裸眼识别。Al^(3+)浓度在2.0~50μmol/L范围内,体系荧光强度呈现出良好的线性关系,检出限为0.033μmol/L,探针S与Al^(3+)形成1∶1的配合物。通过荧光光谱研究了荧光探针S-Al^(3+)配合物与DNA的相互作用,实验结果表明,探针S-Al^(3+)配合物对DNA的猝灭过程为动态猝灭,同时对不同温度下相互作用的结合点常数、结合位点数及热力学参数进行了计算,推断二者作用力的类型为疏水作用,作用方式为嵌插作用。

Synthesis of 3-hydroxyflavone fluorescent probes and study of their fluorescence properties

Direct measurement of dipole potential in biological membranes has been impossible and 3-hydroxyflavones(3HFs) have allowed detection of changes in dipole potential in biological systems.In the present study,sixteen derivatives of 3HF with aliphatic hydrocarbon chains of different lengths at 4′-position and 6-position were synthesized.The basic fluorescence properties of 3HFs are maintained in all the probes in terms of strong blue shift in maximum fluorescence emission wavelength and>100 fold increase in quantum yield in organic solvents and in dioleoylphosphatidylcholine(DOPC) small unilamellar vesicles(SUV) in comparison to in aqueous Hepes buffer(15 mmol/L,pH 7.4).More importantly,the ability of the new compounds to report dipole potential changes in biological systems are also maintained,since all the new probes showed spectrum properties that are similar to yet different from that of F4N1,which potentially may allow more sensitive measurement of the dipole potential change in membranes.

Design of functionalized fluorescent ionic liquid and its application for achieving significant improvements in Al^3t detecting

Specific fluorophore was introduced into ionic liquid based on its tunability,thus a kind of novel fluorescent ionic liquid probe[P66614][HQS]was designed,synthesized and characterized.Compared with non-fluorescent HQS,ionic liquid[P66614][HQS]emitted a certain amount of fluorescence,which could be attributed to the well-delocalized frontier orbitals and its charge transfer character,as demonstrated by quantum chemical calculation.Considering the interaction of[P66614][HQS]with metal ions,the application for detecting specific substance as a chemical sensor,such as Al3+was investigated.Compared with the traditional probe HQS,significant improvements in Al^3+detecting was achieved by[P66614][HQS]with stronger binding ability,better sensitivity and selectivity.The better performance of[P66614][HQS]was contributed to the changed charge distribution,leading to the stronger binding interaction.We believe that this new fluorescent ionic liquid exhibited unique properties in detecting Al^3+in aqueous solution,which would broaden the application of ionic liquids.

用于痕量监测Zr^(4+)、Cr_(2)O_(7)^(2-)、Fe^(3+)、HPO_(4)^(2-)和指纹识别的功能化Eu^(3+)/Tb^(3+)配位聚合物荧光探针的构筑

采用芳香族π共轭及含氮原子有机连接剂,合成同构铽、铕发光配位聚合物(CPs){[Eu(PLIA)_(1.5)(H_(2)O)_(2)]·H_(2)O}_(n)(1)和{[Tb(PLIA)_(1.5)(H_(2)O)_(2)]·H_(2)O}_(n)(2),其中H_(2)PLIA=5-((吡啶-4-基甲基)氧基)苯-1,3-二甲酸。对合成的配合物进行了结构测定、表征和荧光痕量识别实验研究。2个同构配合物具有理想的三维框架结构,π…π堆积及氢键等弱相互作用增强了其化学稳定性;表征显示配位聚合物1和2具有良好的荧光性质、结晶性、热力学稳定性及结构完整性,可作为荧光传感的材料。1和2对水溶液中的Zr^(4+)、Cr_(2)O_(7)^(2-)和Fe^(3+)、HPO_(4)^(2-)具有选择性好、灵敏度高的荧光识别能力,其检出限分别为0.139μmol·L^(-1)(1,Zr^(4+))、0.626μmol·L^(-1)(1,Cr_(2)O_(7)^(2-))、0.430μmol·L^(-1)(2,Fe^(3+))、1.36μmol·L^(-1)(2,HPO_(4)^(2-))。探究了1和2作为探针的荧光猝灭机理。更有趣的是,1和2具有指纹识别性能,其荧光指纹纹路清晰连贯,细节明显,可被清晰观察。

基于N掺杂Ti_(3)C_(2)MXene量子点的荧光探针用于Hg2+和S2-的传感检测

基于N掺杂Ti_(3)C_(2) MXene量子点(N-Ti_(3)C_(2) MQDs)荧光探针和配位相互作用,构建了一种检测Hg^(2+)和S^(2-)的“开-关-开”型荧光传感新方法.研究发现,制备的N-Ti_(3)C_(2) MQDs发射蓝色荧光(λem=440 nm),荧光量子产率为15.7%.Hg^(2+)与N-Ti_(3)C_(2) MQDs表面的—NH2,—COOH,—OH等官能团产生选择性配位作用,导致N-Ti_(3)C_(2) MQDs体系荧光猝灭.当加入S^(2-)后,由于S^(2-)与Hg^(2+)之间强的结合力,形成HgS沉淀,从而使N-Ti_(3)C_(2) MQDs体系荧光恢复.基于该原理,构建了一种“开-关-开”型荧光传感方法,实现了对Hg^(2+)和S^(2-)的定量检测.N-Ti_(3)C_(2) MQDs探针的荧光强度与Hg^(2+)浓度在0.02~200μmol/L范围内呈良好线性关系,检出限为10 nmol/L(S/N=3);与S^(2-)浓度在0.07~150μmol/L范围内呈良好线性关系,检出限为30 nmol/L(S/N=3).该方法具有成本低、操作简单、灵敏度高和选择性好等特点,并可用于水样中Hg^(2+)和S^(2-)的检测.

氮掺杂Ti_(3)C_(2)MXene量子点荧光探针用于α-葡萄糖苷酶活性检测

α-葡萄糖苷酶是生物体糖代谢途径中不可或缺的一类酶,发展简单、灵敏、准确的α-葡萄糖苷酶活性检测及抑制剂筛选方法对于糖尿病的治疗与预防具有重要意义。该文基于氮掺杂Ti_(3)C_(2)MXene量子点(NTi_(3)C_(2)MQDs)荧光探针和内滤效应(IFE),构建了一种“开-关-开”型荧光传感α-葡萄糖苷酶活性检测及抑制剂筛选的新方法。研究发现,N-Ti_(3)C_(2)MQDs发射蓝色荧光(λem=440 nm),荧光量子产率为15.7%。其检测机理为:α-葡萄糖苷酶水解底物对硝基苯基-α-D-吡喃葡萄糖苷,水解产物对硝基苯酚通过内滤效应导致NTi_(3)C_(2)MQDs荧光猝灭;而抑制剂阿卡波糖可使α-葡萄糖苷酶的活性受到抑制,水解产物减少,N-Ti_(3)C_(2)MQDs荧光恢复。结果显示,N-Ti3C2 MQDs探针荧光强度与α-葡萄糖苷酶浓度在5~300 U/L范围内呈良好线性关系,检出限为2.5 U/L(S/N=3),对阿卡波糖的半最大抑制浓度(IC_(50))为178.5μmol/L。该方法具有成本低、操作简单、灵敏度高、选择性好等特点,已成功用于人血清中α-葡萄糖苷酶活性的测定。

基于Eu^(3+)-生物质碳量子点探针的比率型荧光传感体系检测盐酸四环素

该文以橙皮为原料制备的碳量子点(CDs)与铕离子(Eu^(3+))构建双发射比率型荧光探针(Eu^(3+)-CDs)并用于抗生素盐酸四环素的检测。在370 nm激发波长下,Eu^(3+)-CDs荧光探针在425 nm处出现较强的蓝色荧光峰,在617 nm处出现较弱的红色荧光峰。随着盐酸四环素浓度的逐渐增大,Eu3+与盐酸四环素螯合形成的配合物增多,在425 nm处的CDs荧光(I_(F425))逐渐减弱,而617 nm处铕配合物的荧光(I_(F617))逐渐增强,可基于荧光强度比I_(F617)/I_(F425)的变化对盐酸四环素进行测定。考察了Eu^(3+)的浓度、pH值和反应时间对探针荧光强度的影响。在最佳条件下,该双发射比率型荧光探针对盐酸四环素具有特异性识别能力,荧光强度比(I_(F617)/I_(F425))与盐酸四环素浓度在10~100µmol/L范围内存在良好的线性关系,相关系数r^(2)=0.9926,检出限为5.09µmol/L。该方法成功用于猪肉中盐酸四环素含量的检测,加标回收率为102%~110%,相对标准偏差为0.20%~2.4%,具有较好的实用性。

LiLu(MoO_(4))_(2):Eu^(3+)的制备及其对Fe^(3+)离子的荧光检测研究

Fe^(3+)在生命过程中扮演着重要的角色,开发一种能够快速定量检测Fe^(3+)离子的荧光探针有着重要意义。采用溶胶-凝胶法成功制备了四方相白钨矿结构的LiLu(MoO_(4))_(2):Eu^(3+)荧光粉,粒径为1~2μm;通过荧光光谱研究了所得荧光粉的光学性质,确定了Eu^(3+)的最佳发光掺杂摩尔浓度为15%。所得LiLu(MoO_(4))_(2):15%Eu^(3+)对Fe^(3+)离子的检测下限为14.4μmol/L,并且具有高选择性和抗干扰性。

Highly Sensitive Acidic pH Fluorescent Probe Based on A Boradiaza-indacene Derivative

A pH-sensor with a pKa value of 5.05 based on 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene（BODIPY） dye was synthesized and demonstrated to be highly sensitive within a pH range of 4.0--6.0 and was highly photostable, which makes it a potential pH fluorescent probe. The new pH-sensor will find its application in studying acidic organelles in living cells.

Tb^(3+)离子发光探针研究Ca^(2+),La^(3+)和Al^(3+)与拟南芥钙调素的竞争结合

利用Tb3+ 离子的发光 ,研究了Tb3+ 与拟南芥钙调素 (CaM )结合的荧光光谱及荧光滴定曲线特点 ,然后利用Tb3+ 4·CaM系统在 2 2 1nm直接激发和 2 80nm敏化激发的光谱变化研究了Ca2 + ,La3+ 和Al3+ 与拟南芥钙调素 (CaM )的竞争结合作用。结果表明 :Tb3+ ,La3+ 与钙调素的竞争结合能力强于Ca2 + ,而Tb3+的竞争结合力又大于La3+ ,Ca2 +与钙调素的结合力远大于Al3+。竞争实验的结果从分子水平上揭示了Tb3+ ,La3+ 和Al3+ 等金属离子生物效应可能的分子机制。

pH值对Ca^(2+)、La^(3+)和Al^(3+)与拟南芥钙调素竞争结合作用的影响

利用Tb3+荧光光谱,通过Tb.CaM系统的特征光谱在加入Ca2+、La3+和Al3+前后荧光强度的改变,研究了pH值对Ca2+、La3+和Al3+与拟南芥钙调素(CaM)竞争结合作用的影响。结果表明,在中性条件下,金属离子与Tb.CaM系统中Tb3+的竞争能力强弱顺序为:La3+>Ca2+>Al3+,与钙调素的结合力为:Tb3+>La3+>Ca2+>Al3+。在pH值等于4.5的酸性条件下,Ca2+、La3+和Al3+与Tb3+的竞争结合能力较中性条件下弱,同时,稀土在酸性条件下的竞争结合力大于Ca2+和Al3+,Al3+与CaM竞争结合能力在酸性条件下大于Ca2+。竞争实验的结果从分子水平上证实了金属离子可取代Ca.CaM中的Ca2+与钙调素产生竞争性结合,模拟Ca2+4.CaM的行为,且pH值对金属离子与钙调素竞争结合力产生一定影响,揭示了胞外钙调素在酸性和金属离子浓度较高的生理条件下生物效应可能的分子机制。

基于ESIPT机理检测Al^3+荧光探针分子结构和电子光谱的理论研究

本文应用密度泛函理论(DFT)和含时密度泛函理论(TD-DFT)方法,研究了具有激发态分子内质子转移(ESIPT)特性的3-羟基黄酮(3HF)及其两种氰基和氨基取代衍生物(3HF-CY和3HF-AM)作为水溶液中Al^3+离子检测的荧光探针分子结构和电子光谱性质.计算得到了与ESIPT过程相关的键长、键角以及势能曲线,模拟计算了单独分子和分子@Al3+复合物的吸收和荧光光谱.结果表明,氰基或氨基的引入均会抑制3HF的质子在基态(S0)或激发态(S1)的转移.而从得到的吸收光谱可以看出,在3HF中引入吸电子基团氰基可以引起其吸收光谱的红移,而给电子基团氨基的引入则出现相反现象.此外,与3HF-AM的荧光光谱相比,3HF-AM@Al^3+复合物发生了75.88 nm的蓝移,由此推测3HF-AM与水中的Al^3+反应后,在光激发下溶液荧光会由绿色转变为紫色,表明3HF-AM分子可以作为有效检测水中Al3+的荧光探针.

罗丹明-三嗪荧光探针对Al^(3+)和Cr^(3+)的识别

用罗丹明B乙二胺分步取代三聚氯氰环上两个氯原子,得到对称结构的罗丹明-三嗪衍生物。在pH 4～6的乙醇溶液中,衍生物能选择性识别Al 3+和Cr3+,荧光发射和紫外-可见吸收显著增强。衍生物对Al 3+和Cr3+识别不受共存金属离子干扰。在一定条件下,可作为高选择性和高灵敏的Al 3+或Cr3+荧光和比色增强型光谱探针。

可视化荧光分子探针合成及对食品中Al^(3+)的检测

基于5,5′-亚甲基双水杨醛和3-氯-2-肼基吡啶,合成了一种双席夫碱荧光探针L,并进行了结构表征。在DMF溶液中,探针可实现对Al^(3+)的“turn-on”可视化检测,并表现出较高的灵敏性和选择性。荧光滴定实验中,Al^(3+)浓度在50~300μmol·L^(-1)内,与荧光强度呈良好线性关系,计算出检测限为9.4×10^(-7)mol·L^(-1)。Job's plot曲线及高分辨质谱数据表明,探针与Al^(3+)结合化学剂量比为2∶1。将该探针应用于市售粉丝Al^(3+)检测中,加标回收率94.4~101.1%,相对标准偏差为3.08%,得到较好实验效果。

基于四苯乙烯-罗丹明B的新型比色Fe^(3+)荧光探针的合成及其性能研究

文章利用2,6-吡啶二甲酰氯“一锅”两步连接四苯基乙烯和罗丹明B两大荧光母体,合成了一种新型比色Fe^(3+)荧光探针L,并对其进行结构表征和性能研究。利用紫外-可见吸收法和分子荧光光谱法研究了L的光学性质,实验结果表明:当Fe^(3+)存在时,探针溶液显示出从无色到橘红色的颜色明显变化和显著的荧光变化。该探针在水溶液中对Fe^(3+)表现出较高选择性和灵敏度,并且具有良好的线性响应范围(30~200μmol/L)和低检测限(5.03×10-6 mol/L),同时还能对Cu^(2+)实现可视化识别。通过ESI-MS研究表明L与Fe^(3+)可1∶1进行络合,导致罗丹明B螺内酰胺诱导开环,引起变色,聚集状态减弱,从而达到选择性识别Fe^(3+).

二氨基马来腈席夫碱Al^(3+)荧光分子探针

以2,4-二羟基苯甲醛和二氨基马来腈为原料合成了Schiff碱型荧光分子探针L,采用FT-IR、~1H NMR和MS对其结构进行了表征.结果表明:在V(乙醇)∶V(4-羟乙基哌嗪乙磺酸)=95∶5(pH=7.2)缓冲溶液中,L能够通过off-on荧光响应选择性识别Al^(3+),且几乎不受其他金属离子的干扰.在Al^(3+)浓度为0~2.4×10-5 mol/L时,溶液荧光强度与Al^(3+)浓度呈现良好的线性关系.L对Al^(3+)检出限为6.693×10^(-9)mol/L,二者的络合常数为2.146×10~4(mol/L)^(-1).

理论预测Al^3+与一种萘酚衍生物荧光探针分子形成配合物的结构

用量子化学方法研究了实验上合成的一种基于萘酚的Al^3+荧光探针分子L的性质.筛选出了L与Al^3+可能形成的配合物的几何结构,并通过电子吸收光谱和荧光光谱进行了验证.在该配合物中,L与Al^3+的络合比为2∶2;Al^3+采用六配位的结构;与萘环相连的氧原子形成氧桥,将两个Al^3+连接起来.最后研究了L与Al^3+生成不同配比化合物的反应焓变和吉布斯自由能变.结果表明,L与Al^3+的络合比为2∶2时反应焓变和吉布斯自由能变最负,反应最可能发生.这一工作加深了人们对这一识别过程的理解.

一种席夫碱Al^(3+)荧光探针的制备及细胞成像应用

以4⁃(二乙氨基)水杨醛与奥肼缩合制备了一例席夫碱类荧光探针1,通过1H NMR、^(13)C NMR和电喷雾电离质谱表征了1的结构。光谱分析实验结果显示,探针1可选择性与Al^(3+)作用,在495 nm处荧光发射峰显著增强。探针对Al^(3+)的检测灵敏度高,检测限低至1.44μmol·L^(-1)。结合理论计算,证实探针以三齿配位的模式,与Al^(3+)形成1∶1型稳定配合物。此外,该探针还可用于活细胞中Al^(3+)的检测。