Satya Athul, Bhattacharjee Ayon
Department of Physics, National Institute of Technology, Bijni Complex, Laitumkhrah, Shillong, Meghalaya 793003, India.
Phys Chem Chem Phys. 2024 Dec 11;26(48):29788-29804. doi: 10.1039/d4cp03205e.
This paper presents a novel prototype for human insulin detection using a 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 time-dependent studies conducted using a polarising optical microscope (POM) on human insulin in the concentration range from 25 μM to 500 μM 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. An RGB (red, green, and blue) and grey index study showed a positive correlation graph with an value of 0.97279, proving the selectivity of the proposed biosensor. Molecular docking and Raman spectroscopy studies 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 interactions. Vibrational studies conducted using Raman spectroscopy analysed the change in 7CB-LC parameters such as the 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.
本文介绍了一种使用4-庚基-4-联苯甲腈液晶（7CB-LC）进行人胰岛素检测的新型原型。人胰岛素对于调节血糖水平以及促进碳水化合物、脂质和蛋白质的代谢至关重要。胰岛素不足会导致高血糖，即细胞无法有效地利用葡萄糖进行能量产生。长期高血糖会影响神经和心血管系统。我们的工作研究了使用7CB-LC作为人胰岛素无标记检测原型的范围。使用偏光光学显微镜（POM）对浓度范围为25μM至500μM的人胰岛素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、预径向和双极纹理。由于在该浓度以下未观察到可区分的纹理，因此观察到检测限为25μM。RGB（红、绿、蓝）和灰度指数研究显示正相关图，相关值为0.97279，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研究，以在分子水平上更多地了解胰岛素与7CB-LC之间的相互作用。对接研究揭示了7CB核心和末端的位置如何与胰岛素的氨基酸残基相互作用。拉曼光谱研究调查了LC不同部分的链段流动性以及由于胰岛素相互作用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））在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如何有可能用于生物传感以检测人胰岛素，因为它在无标记检测方法中提供了更好的可视化效果。
