Multiscale Sensing of Antibody - Antigen Interactions by Organic Transistors and Single-Molecule Force Spectroscopy
Multiscale Sensing of Antibody - Antigen Interactions by Organic Transistors and Single-Molecule Force Spectroscopy
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DOI：
10.1021/acsnano.5b00136
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发表时间：
2015-05-01
期刊：
影响因子：
17.1
通讯作者：
Biscarini, Fabio
中科院分区：
文献类型：
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作者：
Casalini, Stefano;Dumitru, Andra C.;Biscarini, Fabio
抗体-抗原（Ab-Ag）识别是许多生物传感平台的基础上的主要事件。在无标记生物传感器中，发生在固液界面的这些事件是复杂的，并且通常难以在最小长度尺度下至分子尺度上进行技术控制。在此，在用于免疫检测炎性细胞因子（即白细胞介素-4）的真实的电极区域上进行分子尺度技术（如单分子力光谱法）（114）。力距离曲线的统计分析使我们能够量化的概率，特征长度尺度，粘附能，和特定识别的时间尺度。这些结果使我们能够合理化的电解质门控有机场效应晶体管（EGOFET）作为114免疫传感器操作的响应。比较了114种抗体在Au栅电极上固定的两种不同策略：抗体结合到（i）His标记的蛋白G（PG）/Au的光滑膜;（ii）通过戊二醛在Au上的6-氨基己基乙醇（HSC 6 NH 2）自组装单层。用第一官能化策略获得最灵敏的EGOFET（浓度最小检测水平低至5 nM的114）。该结果与在Ab/PG/Au电极上通过力谱检测到的特异性结合事件的最高概率（30%）相关，相比之下，在具有第二官能化的电极上的概率为10%。具体地，这证明Ab/PG/Au产生可用于识别的定向抗体的最大面密度。更一般地说，这项工作表明，在多尺度生物传感器中的特定识别事件可以通过纳米技术进行评估，量化和优化。
Antibody-antigen (Ab-Ag) recognition is the primary event at the basis of many biosensing platforms. In label-free biosensors, these events occurring at solid liquid interfaces are complex and often difficult to control technologically across the smallest length scales down to the molecular scale. Here a molecular-scale technique, such as single-molecule force spectroscopy, is performed across areas of a real electrode functionalized for the immunodetection of an inflammatory cytokine, viz. interleukin-4 (114). The statistical analysis of force distance curves allows us to quantify the probability, the characteristic length scales, the adhesion energy, and the time scales of specific recognition. These results enable us to rationalize the response of an electrolyte-gated organic field-effect transistor (EGOFET) operated as an 114 immuno-sensor. Two different strategies for the immobilization of 114 antibodies on the Au gate electrode have been compared: antibodies are bound to (i) a smooth film of His-tagged protein G (PG)/Au; (ii) a 6-aminohexanethiol (HSC6NH2) self-assembled monolayer on Au through glutaraldehyde. The most sensitive EGOFET (concentration minimum detection level down to 5 nM of 114) is obtained with the first functionalization strategy. This result is correlated to the highest probability (30%) of specific binding events detected by force spectroscopy on Ab/PG/Au electrodes, compared to 10% probability on electrodes with the second functionalization. Specifically, this demonstrates that Ab/PG/Au yields the largest areal density of oriented antibodies available for recognition. More in general, this work shows that specific recognition events in multiscale biosensors can be assessed, quantified, and optimized by means of a nanoscale technique.