Miniature multiplexed label-free pH probe in vivo
Miniature multiplexed label-free pH probe in vivo
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DOI：
10.1016/j.bios.2020.112870
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发表时间：
2021-02-15
影响因子：
12.6
通讯作者：
Yoshinobu, Tatsuo
中科院分区：
文献类型：
--
作者：
Guo, Yuanyuan;Werner, Carl Frederik;Yoshinobu, Tatsuo
由于缺乏体内技术来精确确定局部pH值变化，因此将脑内pH值波动与病理生理学相关联受到阻碍。在这里，我们开发了一种基于场效应pH传感器的一体化pH探针，用于空间分辨和无标记的体内pH传感，即，光可寻址电位传感器（LAPS），其耦合到柔性多模光纤。从调制光源引出的LAPS的读出光电流记录了与pH变化成比例的局部表面电位变化。在通过具有不同调制频率的多个光源在多个点处同时照射时，通过对该光电流进行解复用来获得多个指定点处的pH变化。为了使其在体内的应用，我们结合了LAPS与多峰纤维制造的收敛热拉伸。这种光纤在中心无缝集成了多芯光波导，用于光传输，周围分别有用于引出光电流的电极和用作伪参考电极。这种混合一体化pH探针可以同时测量14个像素的pH变化，空间分辨率为250 pm，时间分辨率为30 Hz。pH灵敏度在所有可测量的像素上均匀地表征为57.5 +/-2.2 mV/pH。这种探针已被植入到大鼠的海马结构中，并在生理和病理条件下评估其在多个像素处捕获pH变化的能力。这里开发的技术代表了一类新的体内化学传感技术，能够以高空间和时间分辨率对脑深部结构中的内在化学信号进行空间分辨调查。
Correlating in-brain pH fluctuations with the pathophysiology has been impeded by the lack of in vivo techniques to precisely determine local pH changes. Here, we developed an all-in-one pH probe for spatially-resolved and label-free pH sensing in vivo, based on a field-effect pH sensor, i.e., a light-addressable potentiometric sensor (LAPS), coupled to a flexible multimodal fiber. A readout photocurrent from the LAPS, elicited from a modulated light source, registers the localized surface potential change, proportional to the pH change. Upon simultaneous illuminations at multi-spot by a plurality of light sources with different modulation frequencies, pH changes at multiple designated spots are obtained via demultiplexing this photocurrent. To enable its in vivo applications, we combined the LAPS with a multimodal fiber fabricated by the convergence thermal drawing. Such fiber seamlessly integrates a multicore optical waveguide in the center for the light delivery, surrounded by electrodes for leading out photocurrent and serving as a pseudo-reference electrode, respectively. Such hybrid all-in-one pH probes can measure pH changes at 14 pixels simultaneously with a spatial resolution of 250 pm and a temporal resolution of 30 Hz. The pH sensitivity was characterized as 57.5 +/- 2.2 mV/pH homogeneously across all measurable pixels. Such probes have been implanted into the hippocampal formation of rats and their capabilities to capture pH changes at multiple pixels were evaluated at both physiological and pathological conditions. Technologies developed here represents a new class of in vivo chemical sensing technologies enabling the spatially-resolved investigation of intrinsic chemical signals in deep brain structures with high spatial and temporal resolutions.