Department of Bioengineering, Imperial College London, London SW7 2AZ, U.K.
Department of Materials, Imperial College London, London SW7 2AZ, U.K.
Anal Chem. 2021 May 4;93(17):6646-6655. doi: 10.1021/acs.analchem.0c05108. Epub 2021 Apr 2.
Developing tools that are able to monitor transient neurochemical dynamics is important to decipher brain chemistry and function. Multifunctional polymer-based fibers have been recently applied to monitor and modulate neural activity. Here, we explore the potential of polymer fibers comprising six graphite-doped electrodes and two microfluidic channels within a flexible polycarbonate body as a platform for sensing pH and neurometabolic lactate. Electrodes were made into potentiometric sensors (responsive to pH) or amperometric sensors (lactate biosensors). The growth of an iridium oxide layer made the fiber electrodes responsive to pH in a physiologically relevant range. Lactate biosensors were fabricated via platinum black growth on the fiber electrode, followed by an enzyme layer, making them responsive to lactate concentration. Lactate fiber biosensors detected transient neurometabolic lactate changes in an in vivo mouse model. Lactate concentration changes were associated with spreading depolarizations, known to be detrimental to the injured brain. Induced waves were identified by a signature lactate concentration change profile and measured as having a speed of ∼2.7 mm/min ( = 4 waves). Our work highlights the potential applications of fiber-based biosensors for direct monitoring of brain metabolites in the context of injury.
开发能够监测瞬时神经化学动力学的工具对于破译大脑化学和功能非常重要。基于多功能聚合物的纤维最近已被应用于监测和调节神经活动。在这里，我们探索了一种聚合物纤维的潜力，该纤维由 6 个掺石墨电极和 2 个微流道组成，位于柔性聚碳酸酯主体内，作为一种用于感应 pH 值和神经代谢物乳酸的平台。电极被制成为电位传感器（对 pH 值有响应）或电流传感器（乳酸生物传感器）。氧化铱层的生长使纤维电极能够在生理相关范围内对 pH 值做出响应。通过在纤维电极上生长铂黑，制造了乳酸生物传感器，然后是酶层，使它们对乳酸浓度有响应。乳酸纤维生物传感器检测到体内小鼠模型中瞬时神经代谢乳酸的变化。已知乳酸浓度的变化与扩散性去极化有关，这对受伤的大脑是有害的。诱导波通过特征性的乳酸浓度变化模式来识别，并测量为具有约 2.7mm/min（=4 个波）的速度。我们的工作强调了基于纤维的生物传感器在损伤背景下直接监测脑代谢物的潜在应用。
