Detection of K+ Efflux from Stimulated Cortical Neurons by an Aptamer-Modified Silicon Nanowire Field-Effect Transistor
Detection of K+ Efflux from Stimulated Cortical Neurons by an Aptamer-Modified Silicon Nanowire Field-Effect Transistor
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DOI：
10.1021/acssensors.6b00505
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发表时间：
2017-01-01
期刊：
影响因子：
8.9
通讯作者：
Chen, Yit-Tsong
中科院分区：
文献类型：
--
作者：
Anand, Ankur;Liu, Chia-Rung;Chen, Yit-Tsong
神经元细胞膜上 K+ 的浓度梯度决定了其静息电位和细胞兴奋性。在神经传递过程中，K+通过各种通道从细胞中流出，不仅会降低细胞内的K+含量，还会升高细胞外的IC浓度。然而，目前尚不清楚这种变化会达到何种程度。在这项研究中，我们开发了一种用 K+ 特异性 DNA 适体（适体/SiNW-FET）修饰的多并联硅纳米线场效应晶体管（SiNW-FET），用于实时检测培养的皮层神经元的回流。适体/SiNW-FET 显示出针对 K+ 的关联常数为 (2.18 +/- 0.44) x 10(6) M-1，并且对其他碱金属离子的反应较小或可忽略不计。在无 Na+/K+ 的缓冲液下，α-氨基-3-羟基-5-甲基-4-异恶唑丙酸 (AMPA) 刺激诱导外向电流并使全细胞修补神经元的膜电位超极化。当神经元被放置在不含 Na+/K+ 的缓冲液中的适体/ SiNW-FET 上时，AMPA (13 μM) 刺激将细胞外 K+ 浓度升高至接近 800 nM，而 AMPA 受体拮抗剂 6,7-二硝基喹喔啉-2,3-二酮可大大降低该浓度。 AMPA 提高细胞外 K+ 浓度的 EC50 为 10.3 μM。通过在正常生理缓冲液下用 AMPA 刺激神经元，分离的胞质级分中的 K+ 浓度降低了 75%。这些实验表明，适体/SiNW-FET 对于检测阳离子非常敏感，并且可以极大地改变神经元内部和外部的 K+ 浓度以调节神经元的兴奋性。
The concentration gradient of K+ across the cell membrane of a neuron determines its resting potential and cell excitability. During neurotransmission, the efflux of K+ from the cell via various channels will not only decrease the intracellular K+ content but also elevate the extracellular IC-concentration. However, it is not clear to what extent this change could be. In this study, we developed a multiple-parallel-connected silicon nanowire field-effect transistor (SiNW-FET) modified with K+-specific DNA-aptamers (aptamer/SiNW-FET) for the real-time detection of the r efflux from cultured cortical neurons. The aptamer/SiNW-FET showed an association constant of (2.18 +/- 0.44) x 10(6) M-1 against K+ and an either less or negligible response to other alkali metal ions. The alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) stimulation induced an outward current and hyperpolarized the membrane potential in a whole-cell patched neuron under a Na+/K+-free buffer. When neurons were placed atop the aptamer/ SiNW-FET in a Na+/K+-free buffer, AMPA (13 mu M) stimulation elevated the extracellular K+ concentration to similar to 800 nM, which is greatly reduced by 6,7-dinitroquinoxaline-2,3-dione, an AMPA receptor antagonist. The EC50 of AMPA in elevating the extracellular K+ concentration was 10.3 mu M. By stimulating the neurons with AMPA under a normal physiological buffer, the K+ concentration in the isolated cytosolic fraction was decreased by 75%. These experiments demonstrate that the aptamer/SiNW-FET is sensitive for detecting cations and the K+ concentrations inside and outside the neurons could be greatly changed to modulate the neuron excitability.