Department of Gastroenterology, Facultyof Medicine, Erciyes University, Kayseri, 38039, Turkey.
Department of Analytical Chemistry, Faculty of Pharmacy, Erciyes University, Kayseri, 38039, Turkey.
Braz J Microbiol. 2023 Jun;54(2):897-905. doi: 10.1007/s42770-023-00989-1. Epub 2023 May 8.
In this work, we developed novel colorimetric biosensors consisting of anthocyanin-rich either black carrot (Daucus carota ssp. sativus var. atrorubens Alef.) or red cabbage (Brassica oleracea) extracts for rapid, sensitive, and economic detection of Helicobacter pylori (H. pylori). We comparatively prepared two test solutions as biosensors including anthocyanin-rich black carrot extract (Anth@BCE) and red cabbage extract (Anth@RCE), both of which fixed to pH 2.5 and investigated their colorimetric responses based on electronic structure and electron density of anthocyanins. We successfully used anthocyanin-rich BCE and RCE as natural pH indicators in detection of H. pylori and introduced their advantages like non-toxicity, easy accessibility, and high stability compared to synthetic indicators. The BCE and RCE tests gave the best color change in the presence of 10 CFU/mL (at 60 min) and 10 CFU/mL (at 75 min) H. pylori suspensions prepared in an artificial gastric fluid. The limit of detection was down to 10 CFU/mL for RCE and BCE tests by increasing incubation time (≥ 5 h). We further made an additional study that color differences in the colorimetric responses observed by naked eyes were supported by digital image processing with RGB (Red Green Blue) and Delta-E (ΔE) analysis. It is confirmed that results evaluated by naked eyes and digital image processing are well consistent with each other. These findings proposed that these colorimetric tests can be implemented to pH dependent detection of various microorganisms and can be effectively transferred from laboratory work to clinics in the near future.
在这项工作中，我们开发了新型比色生物传感器，由富含花色苷的黑胡萝卜（Daucus carota ssp. sativus var. atrorubens Alef.）或红甘蓝（Brassica oleracea）提取物组成，用于快速、灵敏、经济地检测幽门螺杆菌（H. pylori）。我们比较地制备了两种测试溶液作为生物传感器，包括富含花色苷的黑胡萝卜提取物（Anth@BCE）和红甘蓝提取物（Anth@RCE），它们都固定在 pH 2.5 并根据花色苷的电子结构和电子密度研究了它们的比色响应。我们成功地将富含花色苷的 BCE 和 RCE 用作检测 H. pylori 的天然 pH 指示剂，并与合成指示剂相比，介绍了它们的优点，如无毒、易于获得和高稳定性。BCE 和 RCE 测试在人工胃液中制备的 10 CFU/mL（60 分钟时）和 10 CFU/mL（75 分钟时）H. pylori 悬浮液存在时给出了最佳的颜色变化。通过增加孵育时间（≥5 小时），RCE 和 BCE 测试的检测限降低到 10 CFU/mL。我们进一步进行了一项额外的研究，通过 RGB（红-绿-蓝）和 Delta-E（ΔE）分析的数字图像处理支持肉眼观察到的比色响应中的颜色差异。结果表明，通过肉眼和数字图像处理评估的结果彼此非常一致。这些发现表明，这些比色测试可以用于依赖 pH 的各种微生物的检测，并可以在不久的将来有效地从实验室工作转移到临床。
