Human immunoglobulin (HIgG) has gained recognition as a crucial biomarker diagnosing and treating various diseases, particularly in identifying elevated serum levels in conditions like measles and pneumococcal disease. Traditional detection methods, however, are often hindered by inefficiencies, high costs, and potential inaccuracies, underscoring the urgent need for more sensitive, efficient, accurate, and self-calibration methods for HIgG. Here, a novel ZnIn2S4/SnO2 composites was synthesized, featuring uniformly dispersed SnO2 nanoparticles on the flower-like ZnIn2S4 structure, resulting in a type II heterojunction that promotes the separation and transfer of photogenerated carriers. Under optimized conditions, this composite demonstrated remarkable photocurrent enhancements 52 and 195 times greater than that of the individual ZnIn2S4 or SnO2, respectively. A novel dual-mode biosensing platform was subsequently developed, employing the ZnIn2S4/SnO2 composites as both as the photoelectrochemical (PEC) signal generator and antibody carrier. This system utilizes multifunctional CuO NPs with ascorbic acid oxidase-like properties, serving as a secondary antibody label. Upon specific binding to HIgG, a notable decrease in the PEC response occurs due to the catalytic activity of CuO NPs and the antigen-antibody interactions. The introduction of o-phenylenediamine (OPD) further enhances detection by facilitating the formation of a fluorescent substance DHAA. This dual-signal approach yielded excellent linear correlations between both PEC and fluorescence signals and HIgG concentration, achieving low detection limits of 22.5 pg/mL or 8.6 pg/mL. These two signals originated from the same PEC electrode with continuous detection in the absence and presence of OPD, simplifying experimental procedures and enhancing the reliability of detection. The non-toxic, chemically stable ZnIn2S4/SnO2 composites ensures reliable and sensitive detection through photocurrent output after incubation with biomolecules. The integration of nanozyme catalysis, biospecific reactions, and in situ fluorescent products generation promise high selectivity across diverse immunosensing applications.

中文翻译：

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在基于 ZnIn2S4/SnO2 的系统中通过氧化铜纳米酶催化、荧光物质生成和光电化学改变对人免疫球蛋白进行双模式检测


人免疫球蛋白 （HIgG） 已成为诊断和治疗各种疾病的重要生物标志物，特别是在识别麻疹和肺炎球菌疾病等疾病中血清水平升高方面。然而，传统的检测方法往往受到效率低下、成本高和潜在不准确的阻碍，这凸显了对更灵敏、高效、准确和自校准的 HIgG 方法的迫切需求。在这里，合成了一种新型的 ZnIn2S4/SnO2 复合材料，在花状 ZnIn2S4 结构上均匀分散的 SnO2 纳米颗粒，从而产生促进光生载流子分离和转移的 II 型异质结。在优化条件下，这种复合材料表现出显着的光电流增强，分别是单个 ZnIn2S4 或 SnO2 的 52 倍和 195 倍。随后开发了一种新的双模式生物传感平台，采用 ZnIn2S4/SnO2 复合材料作为光电化学 （PEC） 信号发生器和抗体载体。该系统利用具有抗坏血酸氧化酶样特性的多功能 CuO NP 作为二抗标记。与 HIgG 特异性结合后，由于 CuO NPs 的催化活性和抗原-抗体相互作用，PEC 反应显着降低。邻苯二胺 （OPD） 的引入通过促进荧光物质 DHAA 的形成进一步增强了检测。这种双信号方法在 PEC 和荧光信号与 HIgG 浓度之间产生了极好的线性相关性，实现了 22.5 pg/mL 或 8.6 pg/mL 的低检测限。 这两个信号来自同一个 PEC 电极，在不存在 OPD 的情况下进行连续检测，简化了实验程序并提高了检测的可靠性。无毒、化学稳定的 ZnIn2S4/SnO2 复合材料可确保在与生物分子孵育后通过光电流输出进行可靠和灵敏的检测。纳米酶催化、生物特异性反应和原位荧光产物生成的整合有望在各种免疫传感应用中实现高选择性。