Diamond possesses many favorable properties for biochemical sensors, including biocompatibility, chemical inertness, resistance to biofouling, an extremely wide potential window, and low double-layer capacitance. The hardness of diamond, however, has hindered its applications in neural implants due to the mechanical property mismatch between diamond and soft nervous tissues. Here, we present a flexible, diamond-based microelectrode probe consisting of multichannel boron-doped polycrystalline diamond (BDD) microelectrodes on a soft Parylene C substrate. We developed and optimized a wafer-scale fabrication approach that allows the use of the growth side of the BDD thin film as the sensing surface. Compared to the nucleation surface, the BDD growth side exhibited a rougher morphology, a higher sp³ content, a wider water potential window, and a lower background current. The dopamine (DA) sensing capability of the BDD growth surface electrodes was validated in a 1.0 mM DA solution, which shows better sensitivity and stability than the BDD nucleation surface electrodes. The results of these comparative studies suggest that using the BDD growth surface for making implantable microelectrodes has significant advantages in terms of the sensitivity, selectivity, and stability of a neural implant. Furthermore, we validated the functionality of the BDD growth side electrodes for neural recordings both in vitro and in vivo. The biocompatibility of the microcrystalline diamond film was also assessed in vitro using rat cortical neuron cultures.

金刚石具有许多用于生化传感器的有利特性，包括生物相容性、化学惰性、抗生物污染、极宽的电位窗口和低双层电容。然而，由于金刚石与软神经组织之间的机械性能不匹配，金刚石的硬度阻碍了其在神经植入物中的应用。在这里，我们提出了一种灵活的、基于金刚石的微电极探针，该探针由软聚对二甲苯 C 基板上的多通道掺硼多晶金刚石 (BDD) 微电极组成。我们开发并优化了一种晶圆级制造方法，允许使用 BDD 薄膜的生长侧作为传感表面。与成核表面相比，BDD 生长侧表现出更粗糙的形态，更高的sp ³含量、更宽的水势窗口和更低的背景电流。BDD 生长表面电极的多巴胺 (DA) 传感能力在 1.0 mM DA 溶液中得到验证，显示出比 BDD 成核表面电极更好的灵敏度和稳定性。这些比较研究的结果表明，使用 BDD 生长表面制造可植入微电极在神经植入物的灵敏度、选择性和稳定性方面具有显着优势。此外，我们验证了 BDD 生长侧电极在体外和体内神经记录的功能。还使用大鼠皮质神经元培养物在体外评估了微晶金刚石膜的生物相容性。