Sensing Chiral Drugs by Using CdSe/ZnS Nanoparticles Capped with N-Acetyl-L-Cysteine Methyl Ester
Sensing Chiral Drugs by Using CdSe/ZnS Nanoparticles Capped with N-Acetyl-L-Cysteine Methyl Ester
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DOI：
10.1002/chem.201300875
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发表时间：
2013-08-12
影响因子：
4.3
通讯作者：
Perez-Prieto, Julia
中科院分区：
文献类型：
--
作者：
Delgado-Perez, Teresa;Bouchet, Lydia M.;Perez-Prieto, Julia
用N-乙酰-L-半胱氨酸甲酯(CysP)处理商业上的氨基封端的量子点，合成了核或壳大小不同、光学性质不同的手性量子点。有趣的是，他们的胶体甲醇溶液在几个月内保持稳定。它们的核磁共振和红外光谱与CysP通过两个锚定基团--硫酸盐(强结合)和酯基(弱结合)结合在QD表面上一致，而它们的圆二色谱(CD)显示出一个新的宽红移谱带，表明吸附在QD表面上改变了构象平衡，使构象朝着该区域具有旋光性的构象(S)方向变化。这些量子点具有足够的荧光来研究药物的手性识别，特别是芳基丙酸(APAs)、酮洛芬(KP)、萘普生(NP)、氟比洛芬(FP)和布洛芬(IP)。我们使用了不同的药物浓度范围，这取决于QD的溶解度。所有受试药物均以浓度依赖的方式猝灭QD发射。手性量子点(CS@CysP)的猝灭荧光分析表明，它们对KP、NP和FP具有极强的手性识别能力，特别是在KP和FP的情况下，对R对映体有显著的正变构效应。在药物/CS@CysP摩尔比为5000：1和2500：1的情况下，药物的CD光谱的强度和符号的变化证明了药物羧基在QD存在下的解离。
Chiral quantum dots (QDs), differing in their core or shell size and, consequently, in their optical properties, were synthesized by the treatment of commercially available amine-capped quantum dots with methyl ester N-acetyl-l-cysteine (CysP). Interestingly, their colloidal methanol solutions remain stable for several months. Their NMR and IR spectra were in accordance with CysP binding to the QD surface through two anchoring groups; its thiolate (strongly bound) and the carbonyl group of its ester (weaker bound) group, whereas their circular dichroism (CD) spectra showed a new broad redshifted band, suggesting that the attachment to the QD surface modified the conformational equilibrium towards conformer(s) with optical activity in this region. These QDs were sufficiently fluorescent to perform studies of the chiral recognition of drugs, in particular the aryl propionic acids (APAs) ketoprofen (KP), naproxen (NP), flurbiprofen (FP), and ibuprofen (IP). We used different drug concentration ranges, depending on the QD solubility. All the assayed drugs quenched the QD emission in a concentration-dependent mode. Quenching fluorescence assays with the chiral QDs (CS@CysP) showed their extraordinary capacity for the chiral recognition of KP, NP, and FP, and particularly in the case of KP and FP, a remarkable positive allosteric effect was detected for the R enantiomer. By using a drug/CS@CysP molar ratio of 5000:1 and 2500:1, the changes of intensity and the sign of the CD spectrum of the drug evidenced the dissociation of the drug carboxylic group in the presence of the QD.