基于阳离子荧光共轭聚合物和核酸适体探针的蛋白质检测新方法

以核酸适体为识别分子, 阳离子荧光共轭聚合物为报告分子, 建立了一种蛋白质检测新方法. 修饰有荧光熄灭基团的核酸适体探针通过静电作用与阳离子荧光共轭聚合物结合, 导致后者荧光熄灭. 当加入靶蛋白后, 核酸适体探针与其特异性结合, 荧光熄灭基团与阳离子荧光共轭聚合物远离, 聚合物荧光信号得以恢复. 实验结果表明, 荧光恢复程度与靶蛋白的浓度正相关. 采用该方法检测凝血酶的线性范围为17～40 nmol/L.     

基于过氧化物模拟酶催化显色反应的博来霉素比色检测

首次报道了博来霉素(BLM)与亚铁离子相互结合,形成的BLM·Fe(Ⅱ)复合物具有内在的过氧化物模拟酶催化活性,能够催化过氧化氢氧化2,2'-联氮基-双(3-乙基苯并噻唑-6-磺酸)(ABTS)的显色反应,产生深绿色的产物。与天然酶辣根过氧化物酶类似,BLM·Fe(Ⅱ)复合物的催化活性强烈依赖于pH值和温度,相应的最优化条件分别为pH 6.0和30℃。利用BLM·Fe(Ⅱ)复合物催化ABTS的显色反应,建立了一种简便快捷的可视化检测博来霉素的新方法,检出限可达14.1 nmol/L。该检测方法还显示了良好的可重复性和选择性,在临床分析中具有潜在的应用价值。     

基于核壳金@铂纳米粒子的Ag~+比色检测方法

金核铂壳纳米粒子(Au@Pt NPs)具有出色的类过氧化物酶活性,而Ag~+对其催化活性表现出强烈的抑制;基于此,构建了高灵敏的Ag~+比色检测方法。在最佳反应条件下,Au@Pt NPs比色检测Ag~+的线性范围为0.1~10 nmol/L,检出限可达0.05 nmol/L。该方法对汞离子(Hg2~+)也表现出高灵敏的响应,比色检测Hg2~+的线性范围为10~200 nmol/L。将其应用于实际水样中Ag~+的检测,在添加浓度为10,50,100 nmol/L时,回收率为83.8%~97.7%,相对标准偏差为3.0%~9.6%,该方法具有操作简单、灵敏度高、成本低等优点。     

基于免疫磁球的埃博拉病毒糖蛋白高灵敏比色检测

用免疫磁球捕获埃博拉病毒糖蛋白,与生物素化抗体形成免疫夹心复合物,然后链霉亲和素标记辣根过氧化物酶(SA-HRP)催化3,3',5,5'-四甲基联苯胺(TMB)进行显色,通过370 nm处吸光度对病毒糖蛋白进行定量。对免疫磁球进行了免疫荧光表征,通过对照实验验证方法的可靠性,并对检测条件进行了优化。结果表明,吸光度与病毒糖蛋白浓度在1.0~25.0 ng/m L内呈线性关系,检出限达到0.18 ng/m L。该方法重现性较好,特异性好,抗干扰能力强,可实现复杂样品中埃博拉病毒的检测。     

基于碳酸锰纳米氧化酶活性调控比色检测谷胱甘肽

纳米氧化酶是一类具有类似天然氧化酶催化特性的纳米材料.调控纳米氧化酶的催化活性在生物传感和临床诊疗等应用领域具有重要意义.本文通过一步水热法制备了具有高效类氧化酶活性的碳酸锰纳米颗粒(MnCO₃NPs),其能够快速催化溶解氧产生活性氧自由基,从而催化氧化无色底物3,3′,5,5′-四甲基联苯胺(TMB)发生显色反应,其蓝色氧化态产物(ox TMB)在652 nm波长处展现出特征吸收峰.进一步研究发现,在该显色体系中加入谷胱甘肽(GSH)后MnCO₃NPs催化氧化TMB的反应受到抑制,蓝色产物ox TMB的生成减少, 652 nm处的吸光度减弱且与GSH的浓度在一定范围内呈线性关系.基于该原理,本文构建了一种基于MnCO₃NPs类氧化酶活性调控比色检测GSH的新方法,并成功将其用于血清中GSH含量的测定.借助智能手机的拍照和色度分析功能,本文还开发了一种利用智能手机作为检测终端的便携式分析方法用于GSH的检测,该方法有望进一步扩展到床边检测与疾病诊断.     

聚噻吩-b-聚喹喔啉共轭嵌段聚合物对Co~(2+)离子的高选择性可视化检测

探讨了聚(3-己基噻吩)-b-聚(2,3-喹喔啉)(P3HT-b-PQD)共轭嵌段聚合物对二价钴离子的高选择性可视化检测.该类结构明确的嵌段共聚物以Ni(dppp)Cl2为引发剂,通过顺序投料的一锅法活性配位聚合方法合成,其四氢呋喃溶液呈黄色,在365 nm的紫外光照射下发出橙黄色的荧光.该类嵌段聚合物可以实现对二价钴离子的可视化检测,加入二价钴离子后,其四氢呋喃溶液的颜色由黄色变为亮绿色.检测具有非常高的选择性,加入其它的金属离子不能产生溶液颜色的任何变化.此外,加入二价钴离子后,其四氢呋喃稀溶液在紫外下的发射光由橙黄色变为深绿色.其对于二价钴离子的检测限可达10-7mol/L.竞争实验表明,其它金属离子对于钴离子的识别不具有任何干扰.     

基于纳米银的比色阵列传感器的构建及在蛋白质检测中的应用

蛋白质的快速高效检测和鉴定在医学诊断、不同疾病的治疗和蛋白质组学中具有巨大的前景。目前的检测手段大多存在一些问题,如操作繁琐、效率低等,因此开发一个理想的蛋白质检测方法尤为重要。以纳米银(AgNPs)为传感元件的阵列传感器在蛋白质检测方面具有操作便捷、准确率高、可视化等优点。本文合成两种不同颜色和形状的AgNPs:黄色球形和蓝色三角形,以此构建一个简单的比色阵列传感器,用于蛋白质的区分检测。该传感器可以准确地识别和区分不同种类的蛋白质,准确率为100%。在成功识别出不同类型的蛋白质的基础上,进一步评估了该阵列传感器应用于区分正常和变性蛋白质的能力,准确率为96.0%。此外,该阵列传感器对于未知样本的识别也具有高的准确率。     

具有过氧化物酶活性的Imm-Fe3+-IL的制备及用于比色法测定H2O2和葡萄糖

通过溶胶-凝胶法制备的Imm-Fe³⁺-IL纳米材料具有类过氧化物酶的活性,能够催化过氧化氢(H₂O₂)快速氧化3,3′,5,5′-四甲基联苯胺(TMB)产生相应的颜色变化。 稳态动力学分析表明,Imm-Fe³⁺-IL纳米材料遵循典型的Michaelis-Menten模型和乒乓机理。 辣根过氧化物酶(HRP)相比,Imm-Fe³⁺-IL纳米材料纳米材料具有更强的亲和性。 联合葡萄糖氧化酶建立了H₂O₂和葡萄糖的比色检测方法。 结果显示:H₂O₂和葡萄糖的浓度与反应体系的吸光度呈良好的线性关系,H₂O₂的线性范围为1~200 μmol/L,葡萄糖的线性范围为10~200 μmol/L,最低检出限(LOD)分别为0.35和3.31 μmol/L。     

Colorimetric detection of glucose using a boronic acid derivative receptor attached to unmodifed AuNPs简

A simple, cheap and non-enzymatic colorimetric strategy for glucose detection has been designed based on the interactions between a phenylboronic acid （PBA） derivative, which is coupled with gold nanoparticles （AuNPs） as the colorimetric reporters, and glucose. The PBA-AuNPs hybrid system proposed here exhibits ordered photochemistry behaviors upon the addition of glucose at different pH values. There are two linear regions of glucose concentration for the glucose sensor at different pH values, i.e., between 0.1 mmol/L and 9.8 mmol/L at pH 6 with the detection limit of 64μmol/L and between 0 and 6.5 mmol/L with the detection limit of 48 μmol/L at pH 9, respectively. To test the practicality of the sensor system, we also applied this assay to detect a glucose sample in the artificial saliva.     

Colorimetric detection of potassium ions using aptamer-functionalized gold nanoparticles

Herein, a simple and novel colorimetric method for detection of potassium ions (K⁺) was developed. The colorimetric experiments revealed that upon the addition of K⁺, the conformation of anti-K⁺ aptamer in solution changed from random coil structure to compact rigid G-quadruplex one. This compact rigid G-quadruplex structure could not protect AuNPs against K⁺-induced aggregation, and thus the visible color change from wine-red to blue-purple could be observed by the naked eye. The linear range of the colorimetric aptasensor covered a large variation of K⁺ concentration from 5 nM to 1 μM and the detection limit of 5 nM was obtained. Moreover, this assay was able to detect K⁺ with high selectivity and had great potential applications.     

Highly specific quantification of mRNA mutation in single cells based on RNase H cleavage-assisted reverse transcription(RT)-PCR

Accurate quantitation of site-specific mRNA mutation in single cells or in peripheral blood is of great significance for both biological and biomedical studies.How to eliminate the false-positive interference from the abundant normal mRNA is still a big challenge.Herein,we have proposed an LNA(locked nucleic acid)-assisted high-specificity strategy which can selectively guide the RNase H to cleave only the wildtype mRNA(wtRNA) while the mutant mRNA(mutRNA) will remain intact.The intact mutRNA ca...     

A Simple Colorimetric Au-on-Au Tip Sensor with a New Functional Nucleic Acid Probe for Food-borne Pathogen Salmonella typhimurium

An Au-on-Au tip sensor is developed for the detection of Salmonella typhimurium (Salmonella), using a new synthetic nucleic acid probe (NAP) as a linker for the immobilization of a DNA-conjugated Au nanoparticle (AuNP) onto a DNA-attached thin Au layer inside a pipette tip. In the presence of Salmonella, RNase H2 from Salmonella (STH2) cleaves the NAP and the freed DNA-conjugated AuNP can be visually detected by a paper strip. This portable biosensor does not require any electronic, electrochemical or optical equipment. It delivers a detection limit of 3.2×10³ CFU mL⁻¹ for Salmonella in 1 h without cell-culturing or signal amplification and does not show cross-reactivity with several control bacteria. Further, the sensor reliably detects Salmonella spiked in food samples, such as ground beef and chicken, milk, and eggs. The sensor can be reused and is stable at ambient temperature, showing its potential as a point-of-need device for the prevention of food poisoning by Salmonella.     

Colorimetric detection of Ni2+ based on an anionic triphenylmethane dye and a cationic polyelectrolyte in aqueous solution

The combination of xylenol orange (XO) and poly(diallyldimethylammonium chloride) (PDADMAC) has been utilized as a colorimetric sensor for selective recognition of Ni²⁺ in aqueous solution. Upon addition of Ni²⁺, the chemosensor exhibited the significant color change from red to purple with a bathochromic shift, whereas these change was not induced by other metal ions. XO alone did not recognize Ni²⁺ colorimetrically, indicating that PDADMAC was required for detecting Ni²⁺. This study can provide the facile method for the construction of new chemosensors by a simple mixture of an anionic water-soluble dye and cationic polyelectrolyte.     

Colorimetric detection of sodium ion in serum based on the G-quadruplex conformation related DNAzyme activity

There has been a big challenge in developing the Na⁺ sensor that can be practically used in the physiological system with the interference of large amounts of K⁺. In this research, a novel Na⁺ sensor has been designed based on the G-quadruplex-conformation related DNAzyme activity. The sensor exhibits high selectivity and sensitivity with the detection limit of 0.6 μM, which enables the sensor to be practically used in determination of the Na⁺ level in serum. The research not only provides a simple Na⁺ sensor but also opens a new way for developing the detection technology of Na⁺.