Srinivas Sakthivel, Sekar Mouliganesh, Thirumurugan Kavitha, Senthil Kumar Annamalai
Nano and Bioelectrochemistry Research Laboratory, Carbon dioxide Research and Green Technology Centre, Vellore Institute of Technology, Vellore-632 014, India.
Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore-632 014, India.
J Mater Chem B. 2025 Jan 15;13(3):985-996. doi: 10.1039/d4tb01902d.
Hemozoin (HZ, a malarial pigment) is an insoluble crystalline byproduct formed during the intraerythrocytic breakdown of hemoglobin by some blood-feeding parasites, such as . It consists of polymerized iron-porphyrin molecular units linked by carboxylic bonds. Due to the rigid molecular structure, studying the electron transfer activity of HZ is challenging. In this work, we report the development of a redox-active HZ-functionalized multi-walled carbon nanotube (MWCNT) modified glassy carbon electrode (GCE/MWCNT@HZ-redox). Here, HZ-redox refers to the redox-active form of hemozoin. This electrode is designed to study the electron transfer activity and mimic the peroxidase enzyme's ability to mediate hydrogen peroxide reduction in a neutral pH solution. The modified electrode exhibited a stable and well-defined redox peak at -0.385 V Ag/AgCl in N-purged PBS (pH 7.0) with a surface excess value of 1.64 × 10 mol cm. The MWCNT@HZ-redox was characterized using Raman spectroscopy, FT-IR, and FESEM techniques. This biomimicking electrode showed excellent electrocatalytic reduction of HO using cyclic voltammetry. Batch-injection analysis coupled with a screen-printed electrode demonstrated the electroanalytical performance for HO sensing. The electrode exhibited a linear concentration range of 50-300 μM, with a sensitivity of 21 μA μM and a detection limit of 220 nM. As a bioanalytical application, we successfully demonstrated the monitoring of HO within the reactive oxygen species of HCT-116 colon cancer cells under stimulated conditions.
疟原虫色素（HZ，一种疟疾色素）是一些吸血寄生虫（如……）在红细胞内血红蛋白分解过程中形成的不溶性结晶副产物。它由通过羧基键连接的聚合铁卟啉分子单元组成。由于其刚性分子结构，研究HZ的电子转移活性具有挑战性。在这项工作中，我们报道了一种氧化还原活性的HZ功能化多壁碳纳米管（MWCNT）修饰玻碳电极（GCE/MWCNT@HZ-redox）的研制。这里，HZ-redox指的是疟原虫色素的氧化还原活性形式。该电极旨在研究电子转移活性，并模拟过氧化物酶在中性pH溶液中介导过氧化氢还原的能力。在氮气吹扫的pH 7.0的磷酸盐缓冲盐溶液（PBS）中，修饰电极在相对于Ag/AgCl为-0.385 V处呈现出一个稳定且明确的氧化还原峰，表面过剩值为1.64×10 mol/cm²。采用拉曼光谱、傅里叶变换红外光谱和场发射扫描电子显微镜技术对MWCNT@HZ-redox进行了表征。这种仿生电极通过循环伏安法对过氧化氢表现出优异的电催化还原性能。批进样分析结合丝网印刷电极证明了其对过氧化氢传感的电分析性能。该电极的线性浓度范围为50 - 300 μM，灵敏度为21 μA/μM，检测限为220 nM。作为一种生物分析应用，我们成功地展示了在刺激条件下对HCT - 116结肠癌细胞活性氧中的过氧化氢进行监测。
