This paper presents a novel prototype for human insulin detection using 4-heptyl-4-biphenylcarbonitrile liquid crystal (7CB-LC). Human insulin is essential for regulating blood glucose levels and facilitating the metabolism of carbohydrates, lipids, and proteins. Insufficient insulin can lead to hyperglycemia, where cells cannot utilise glucose effectively for energy production. Prolonged hyperglycemia can affect the nervous and cardiovascular systems. Our work investigates the scope of using 7CB-LC as a prototype for the label-free detection of human insulin. Both temperature and the time-dependent study conducted using the polarising optical microscope (POM) for concentrations ranging from 25 μM to 500 μM of human insulin showed that human insulin interacting with 7CB-LC produces radial, twisted-radial, pre-radial and bipolar textures. A detection limit of 25 μM was observed since no distinguishable textures were observed below this concentration. The RGB and grey index study showed a positive correlation graph with an R2 value of 0.97279, proving the selectivity of the proposed biosensor. Molecular docking and Raman spectroscopy were conducted to learn more about the interaction between insulin and 7CB-LC at the molecular level. Docking studies revealed how the position of the 7CB core and tail ends interacted with amino acid residues of insulin. Raman spectroscopy studies investigated the segmental mobility of different parts of LC and changes occurring in the core and terminal regions due to insulin interaction. Vibrational studies conducted using Raman spectroscopy analysed the change in 7CB-LC parameters such as peak position (PP), line width (LW) and integrated intensity (II) on interacting with human insulin. This unique prototype technique shows how 7CB-LC can potentially be employed in biosensing to detect human insulin since it provides better visualisation in a label-free detection method.

中文翻译：

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开发利用 7CB 液晶进行人胰岛素检测的生物传感原型


本文提出了一种使用 4-庚基-4-联苯腈液晶 （7CB-LC） 检测人胰岛素的新型原型。人胰岛素对于调节血糖水平和促进碳水化合物、脂质和蛋白质的代谢至关重要。胰岛素不足会导致高血糖症，细胞无法有效地利用葡萄糖产生能量。长期高血糖会影响神经和心血管系统。我们的工作调查了使用 7CB-LC 作为人胰岛素无标记检测原型的范围。使用偏振光学显微镜 （POM） 对 25 μM 至 500 μM 人胰岛素浓度进行的温度和时间依赖性研究表明，人胰岛素与 7CB-LC 相互作用会产生径向、扭曲径向、前桡状和双极纹理。观察到的检测限为 25 μM，因为在此浓度下未观察到可区分的纹理。RGB 和灰度指数研究显示 R2 值为 0.97279 的正相关图，证明了所提出的生物传感器的选择性。进行了分子对接和拉曼光谱分析，以更多地了解胰岛素和 7CB-LC 在分子水平上的相互作用。对接研究揭示了 7CB 核心和尾端的位置如何与胰岛素的氨基酸残基相互作用。拉曼光谱研究研究了液相色谱不同部分的节段迁移率，以及由于胰岛素相互作用而在核心和末端区域发生的变化。使用拉曼光谱进行的振动研究分析了 7CB-LC 参数（如峰位置 （PP）、线宽 （LW） 和积分强度 （II））与人胰岛素相互作用时的变化。 这种独特的原型技术展示了 7CB-LC 如何潜在地用于生物传感来检测人胰岛素，因为它在无标记检测方法中提供了更好的可视化效果。