Department of Chemistry, American University, Washington, DC 20016, USA.
Biosensors (Basel). 2023 Jun 6;13(6):626. doi: 10.3390/bios13060626.
Cortisol is a vital steroid hormone that has been known as the "stress hormone", which is elevated during times of high stress and anxiety and has a significant impact on neurochemistry and brain health. The improved detection of cortisol is critically important as it will help further our understanding of stress during several physiological states. Several methods exist to detect cortisol; however, they suffer from low biocompatibility and spatiotemporal resolution, and they are relatively slow. In this study, we developed an assay to measure cortisol with carbon fiber microelectrodes (CFMEs) and fast-scan cyclic voltammetry (FSCV). FSCV is typically utilized to measure small molecule neurotransmitters by producing a readout cyclic voltammogram (CV) for the specific detection of biomolecules on a fast, subsecond timescale with biocompatible CFMEs. It has seen enhanced utility in measuring peptides and other larger compounds. We developed a waveform that scanned from -0.5 to -1.2 V at 400 V/s to electro-reduce cortisol at the surface of CFMEs. The sensitivity of cortisol was found to be 0.87 ± 0.055 nA/μM (n = 5) and was found to be adsorption controlled on the surface of CFMEs and stable over several hours. Cortisol was co-detected with several other biomolecules such as dopamine, and the waveform was fouling resistant to repeated injections of cortisol on the surface of the CFMEs. Furthermore, we also measured exogenously applied cortisol into simulated urine to demonstrate biocompatibility and potential use . The specific and biocompatible detection of cortisol with high spatiotemporal resolution will help further elucidate its biological significance and further understand its physiological importance and impact on brain health.
皮质醇是一种重要的类固醇激素，被称为“应激激素”，在高应激和焦虑时会升高，对神经化学和大脑健康有重大影响。提高皮质醇的检测能力至关重要，因为这将有助于我们进一步了解几种生理状态下的应激。有几种方法可以检测皮质醇；然而，它们存在生物相容性和时空分辨率低的问题，而且相对较慢。在这项研究中，我们使用碳纤维微电极 (CFMEs) 和快速扫描循环伏安法 (FSCV) 开发了一种测量皮质醇的测定法。FSCV 通常用于通过产生特定于生物分子的循环伏安图 (CV) 来测量小分子神经递质，以便在快速亚秒级时间尺度上以生物相容的 CFMEs 对生物分子进行快速、灵敏的检测。它在测量肽和其他较大化合物方面的应用得到了增强。我们开发了一种从 -0.5 到 -1.2 V 以 400 V/s 扫描的波形，以在 CFMEs 表面电还原皮质醇。发现皮质醇的灵敏度为 0.87 ± 0.055 nA/μM（n = 5），并且在 CFMEs 表面上受吸附控制，并且在数小时内保持稳定。皮质醇与多巴胺等其他几种生物分子同时检测，该波形对 CFMEs 表面上皮质醇的重复注入具有抗污垢能力。此外，我们还测量了外源性应用于模拟尿液中的皮质醇，以证明其生物相容性和潜在用途。皮质醇的特异性和生物相容性检测具有高时空分辨率，将有助于进一步阐明其生物学意义，并进一步了解其对大脑健康的生理重要性和影响。
