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Enabling electrical biomolecular detection in high ionic concentrations and enhancement of the detection limit thereof by coupling a nanofluidic crystal with reconfigurable ion concentration polarization
Lab on a Chip ( IF 6.1 ) Pub Date : 2017-09-28 00:00:00 , DOI: 10.1039/c7lc00722a
Wei Ouyang 1, 2, 3, 4, 5 , Jongyoon Han 1, 2, 3, 4, 6 , Wei Wang 5, 7, 8, 9, 10
Affiliation  

The regulation effect of surface charges on the transport of electrons in nanomaterials and ions in nanofluidic devices has been widely used to develop highly sensitive and label-free electrical biosensors. The intrinsic limitation to the clinical application of surface charge-effect nano-electrical biosensors is that they usually do not function in physiological conditions normally with high ionic concentrations (∼160 mM), in which the surface charges are screened within a short distance (<1 nm at 160 mM). In this work, we developed a general strategy that enables surface charge-effect electrical biomolecular detection in physiological conditions with an integrated mechanism for enhancement of the limit of detection (LOD) by in situ preconcentration of target molecules during incubation and creation of a transient low ionic concentration environment during the signal read-out step using reconfigurable ion concentration polarization (ICP). We demonstrated the effectiveness of this strategy in a simple nanofluidic biosensor named a nanofluidic crystal (NFC), which can be prepared within hours and without expensive equipment. Our results indicate that the ion depletion effect of ICP could lower the ionic concentration by at least 200 fold and provide a stable ionic environment for over 15 s, enabling electrical detection of proteins and DNAs in serum and urine with LODs of 1–10 nM. We further reconfigured the device to preconcentrate target biomolecules before detection using the enrichment effect of ICP, obtaining LODs of 10–100 pM for proteins and DNAs in physiological conditions. By overcoming the inherent constraint on buffer conditions and the issues regarding fabrication, we believe that this work represents significant progress towards the practical application of surface charge-effect nano-electrical biosensors in point-of-care diagnostics and clinical medicine.

中文翻译:

通过将纳米流体晶体与可重配置的离子浓度极化耦合,可以在高离子浓度下进行电生物分子检测并提高其检测限

表面电荷对纳米材料中的电子和纳米流体设备中的离子传输的调节作用已被广泛用于开发高度敏感且无标签的电子生物传感器。表面电荷效应纳米电生物传感器在临床上的应用的固有局限性在于,它们通常在正常的高离子浓度(〜160 mM)的生理条件下不起作用,其中在短距离内屏蔽表面电荷(<在160 mM处为1 nm)。在这项工作中,我们开发了一种通用策略,该策略能够在生理条件下利用表面机制来原位提高检测限(LOD)的集成机制来实现表面电荷效应电生物分子检测使用可重配置的离子浓度极化(ICP),在孵育过程中对目标分子进行预浓缩,并在信号读取步骤中创建瞬态低离子浓度环境。我们在称为纳米流体晶体(NFC)的简单纳米流体生物传感器中证明了该策略的有效性,该传感器可在数小时内完成制备,而无需昂贵的设备。我们的结果表明,ICP的离子耗竭效应可以将离子浓度降低至少200倍,并在15 s内提供稳定的离子环境,从而能够以1-10 nM的LOD对血清和尿液中的蛋白质和DNA进行电检测。我们通过使用ICP的富集效应,进一步将设备重新配置为在检测之前对目标生物分子进行预浓缩,在生理条件下获得蛋白质和DNA的LOD为10–100 pM。通过克服对缓冲条件和制造问题的固有限制,我们相信这项工作代表着表面电荷效应纳米电生物传感器在即时诊断和临床医学中的实际应用取得了重大进展。
更新日期:2017-11-07
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