Nanostructured Disposable Impedimetric Sensors as Tools for Specific Biomolecular Interactions: Sensitive Recognition of Concanavalin A
Nanostructured Disposable Impedimetric Sensors as Tools for Specific Biomolecular Interactions: Sensitive Recognition of Concanavalin A
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DOI：
10.1021/ac103108m
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发表时间：
2011-04-15
影响因子：
7.4
通讯作者：
Penades, Soledad
中科院分区：
文献类型：
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作者：
Loaiza, Oscar A.;Lamas-Ardisana, Pedro J.;Penades, Soledad
今天，开发传感器来检测特定的微弱生物相互作用仍然是一个具有挑战性的课题。碳水化合物-蛋白质(凝集素)相互作用的特点包括高特异性和低亲和力。本工作开发了纳米结构阻抗传感器，用于检测刀豆蛋白A(ConA)与固定化硫代糖衍生物(D-甘露糖或D-葡萄糖)在金纳米颗粒修饰的丝网印刷碳电极(SPCE)上的结合。以硫代D-半乳糖衍生物为阴性对照，评价了该方法的选择性。将硫代碳水化合物与纳米结构的SPCE结合后，不同官能化的硫醇形成混合自组装单分子膜(SAM)。采用电化学阻抗谱(EIS)技术，通过增加铁/亚铁氰化物氧化还原探针在不同SAM修饰电极上的电子转移电阻来评价ConA与所选碳水化合物的结合。为了优化传感器的性能，对检测方案的不同变量进行了研究。只有通过形成具有足够官能化的硫醇的混合自组装膜，才能实现选择性Con A测定。根据这些硫醇的链长和官能团的不同，得到了重要的差异。对于3-巯基-1-丙磺酸混合自组装膜，D-甘露糖和D-葡萄糖修饰传感器的电子转移电阻与ConA浓度在2.2-40.0mgmL(-1)范围内呈线性关系。在没有任何扩增策略的情况下，D-葡萄糖和D-甘露糖修饰传感器的检出限分别为0.099和0.078 pmol，重复性分别为6.9%和6.1%(n=10)。
The development of sensors to detect specific weak biological interactions is still today a challenging topic. Characteristics of carbohydrate-protein (lectin) interactions include high specificity and low affinity. This work describes the development of nanostructured impedimetric sensors for the detection of concanavalin A (Con A) binding to immobilized thiolated carbohydrate derivatives (D-mannose or D-glucose) onto screen-printed carbon electrodes (SPCEs) modified with gold nanoparticles. Thiolated D-galactose derivative was employed as negative control to evaluate the selectivity of the proposed methodology. After binding the thiolated carbohydrate to the nanostructured SPCEs, different functionalized thiols were employed to form mixed self-assembled monolayers (SAM). Electrochemical impedance spectroscopy (EIS) was employed as a technique to evaluate the binding of Con A to selected carbohydrates through the increase of electron transfer resistance of the ferri/ferrocyanide redox probe at the differently SAM modified electrodes. Different variables of the assay protocol were studied in order to optimize the sensor performance. Selective Con A determinations were only achieved by the formation of mixed SAMs with adequate functionalized thiols. Important differences were obtained depending on the chain lengths and functional groups of these thiols. For the 3-mercapto-1-propanesulfonate mixed SAMs, the electron transfer resistance varied linearly with the Con A concentration in the 2.2-40.0 mu g mL(-1) range for D-mannose and D-glucose modified sensors. Low detection limits (0.099 and 0.078 pmol) and good reproducibility (6.9 and 6.1%, n = 10) were obtained for the D-glucose and D-mannose modified sensors, respectively, without any amplification strategy.