Hybrid CMOS-Graphene Sensor Array for Subsecond Dopamine Detection.
Hybrid CMOS-Graphene Sensor Array for Subsecond Dopamine Detection.
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DOI：
10.1109/tbcas.2017.2778048
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发表时间：
2017-12
影响因子：
5.1
通讯作者：
Shahrjerdi D
中科院分区：
文献类型：
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作者：
Nasri B;Wu T;Alharbi A;You KD;Gupta M;Sebastian SP;Kiani R;Shahrjerdi D
我们介绍了一种混合CMOS-石墨烯传感器阵列，用于通过快扫描循环伏安法（FSCV）亚秒测量多巴胺。原型芯片有四个独立的CMOS读出通道，在65纳米工艺制造。使用平面多层石墨烯作为生物相容的感测材料使得能够将微型化的感测电极直接集成在读出通道上方。利用FSCV的化学特异性，我们引入了一个感兴趣的区域的技术，该技术使用可编程的低噪声恒定电流在约氧化还原电位减去大部分的背景电流。我们证明了该功能的实用性，通过测量传感器响应于已知的多巴胺浓度在体外在三个不同的扫描速率，以提高灵敏度。这种策略进一步使我们能够显著降低模数转换器（ADC）的动态范围要求，而不会影响测量精度。我们表明，一个积分双斜率ADC是足够的数字化的背景扣除电流。ADC工作在5-10 kHz的采样频率下，有效分辨率约为60 pA，这对应于约6 nM的理论多巴胺检测限。我们的混合传感平台为实现下一代FSCV设备提供了有效的解决方案，可以大规模精确记录体内多巴胺信号。
We introduce a hybrid CMOS-graphene sensor array for sub-second measurement of dopamine via fast-scan cyclic voltammetry (FSCV). The prototype chip has four independent CMOS readout channels, fabricated in a 65 nm process. Using planar multilayer graphene as biologically compatible sensing material enables integration of miniaturized sensing electrodes directly above the readout channels. Taking advantage of the chemical specificity of FSCV, we introduce a region of interest technique, which subtracts a large portion of the background current using a programmable low-noise constant current at about the redox potentials. We demonstrate the utility of this feature for enhancing the sensitivity by measuring the sensor response to a known dopamine concentration in vitro at three different scan rates. This strategy further allows us to significantly reduce the dynamic range requirements of the analog-to-digital converter (ADC) without compromising the measurement accuracy. We show that an integrating dual-slope ADC is adequate for digitizing the background-subtracted current. The ADC operates at a sampling frequency of 5-10 kHz and has an effective resolution of about 60 pA, which corresponds to a theoretical dopamine detection limit of about 6 nM. Our hybrid sensing platform offers an effective solution for implementing next-generation FSCV devices that can enable precise recording of dopamine signaling in vivo on a large scale.