Avidity-Based Affinity Enhancement Using Nanoliposome-Amplified SPR Sensing Enables Low Picomolar Detection of Biologically Active Neuregulin 1
Avidity-Based Affinity Enhancement Using Nanoliposome-Amplified SPR Sensing Enables Low Picomolar Detection of Biologically Active Neuregulin 1
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DOI：
10.1021/acssensors.9b01392
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发表时间：
2019-12-01
期刊：
影响因子：
8.9
通讯作者：
Geschwindner, Stefan
中科院分区：
文献类型：
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作者：
Akkilic, Namik;Liljeblad, Mathias;Geschwindner, Stefan
生物标志物用作疾病进展或医疗干预的治疗反应的指标，因此，用于实现可靠且灵敏的生物标志物检测的手段在临床环境中至关重要。大多数生物传感器测定需要与酶或荧光标签组合的高亲和力相互作用以实现检测，并且在信号读出之前经常采用广泛的洗涤程序。通过使用天然生物伴侣来克服这种限制的尝试往往是苛刻的，因为它们非常低的亲和力通常与达到低检测限（LOD）的需要不相容，特别是对于具有短半衰期的循环生物标志物。为了解决这些挑战，我们开发了一种无标记的表面等离子体共振（SPR）平台，用于使用ErbB4修饰的脂质体检测神经调节蛋白1（NRG 1），通过功能性多价相互作用提供信号放大和亲和力增强。通过NRG 1和ErbB4之间的功能性亲合力相互作用，达到了3.5皮摩尔的LOD，这比传统SPR和小型化免疫测定高约60倍。与采用天然结合伴侣而不是高亲和力抗体作为相互作用伴侣之一的单分子免疫测定相比，生物传感器也显示出8倍的高灵敏度。事实上，脂质体诱导的NRG 1和ErbB4之间的亲合力提供了与使用高亲和力抗体获得的LOD相当的LOD，并且能够以36 pM的LOD检测血浆中的NRG 1。因此，结合低亲和力生物标志物受体使用脂质体增强的平台能够在竞争性LOD下评估生物标志物的功能状态，并且消除了对高亲和力抗体的需要。
Biomarkers serve as indicators of disease progression or therapeutic response of an medical intervention, and means for enabling a reliable and sensitive biomarker detection are therefore vital in clinical settings. Most biosensor assays require high-affinity interactions in combination with an enzyme or fluorescent tag to enable detection and frequently employ extensive washing procedures prior to signal readout. Attempts to overcome this limitation by using natural biological partners tend to be demanding, because their very low affinity is frequently not compatible with the need of reaching low limits of detection (LODs), especially for circulating biomarkers that possess short half-lives. To address these challenges, we developed a label-free surface plasmon resonance (SPR) platform for the detection of neuregulin 1 (NRG1) using ErbB4-modified liposomes offering both signal amplification and affinity enhancement via functional multivalent interactions. Through the functional avidity interaction between NRG1 and ErbB4, an LOD of 3.5 picomolar was reached, which is about 60-fold higher than traditional SPR and miniaturized immunoassays. The biosensor displays also an 8-fold higher sensitivity when compared with a single-molecule immunoassay employing the natural binding partner rather than a high-affinity antibody as one of the interaction partners. In fact, the liposome-induced avidity between NRG1 and ErbB4 offered an LOD that was comparable to that obtained using a high-affinity antibody and enabled detection of NRG1 in plasma with a LOD of 36 pM. Employing the liposome-enhanced platform in conjunction with a low-affinity biomarker receptor thus enables the assessment of the functional state of the biomarker at competitive LODs and eliminates the need for high-affinity antibodies.