Liu Jing, Chen Ye, Huang Hongjie, Chen Feixiong
Department of Research, Shanghai University of Medicine and Health Sciences Affliated Zhoupu Hospital, The College of Medical Technology, Shanghai University of Medicine and Health Sciences, Shanghai, 201318, China.
Huangyan District Center for Disease Control and Prevention, Taizhou, 318020, Zhejiang, China.
Discov Nano. 2025 May 2;20(1):74. doi: 10.1186/s11671-025-04250-6.
Magnetic nanoparticles (MNPs) hold significant potential for a wide range of applications, however, surface modification or bio-conjugation of MNPs often leads to their aggregation and instability. To address this, we proposed a facile method using a layer-by-layer (LbL) coating technique with polyallylamine hydrochloride (PAH) and poly(styrene sulfonic acid) sodium salt (PSS), so as to maintain the dispersion stability and functionality of MNPs. This method enabled us to develop the powerful MNPs towards to their use in the electrochemical biosensor, by combining both the redox probes (ferrocene (Fc), anthraquinone (AQ), or monocarboxymethylene blue (MB)) and bio-probes (IgG). The redox molecules were effectively anchored to the MNPs under the organic solvents, while such functionalized MNPs surface were subsequently protected by the LbL coating process prior to dispersing in high ionic strength solutions (e.g. Phosphate-buffered saline). And the out-layer of polyelectrolyte shell allowed biomolecules to attach to the MNP surface without chemical cross-linking. Our results demonstrated that the TEM size of MNPs@Fc, MNP@AQ and MNP@MB after LbL coating were characterized as 11.0 ± 2.0 nm, 10.5 ± 2.1 nm and 12.4 ± 2.2 nm and these developed redox MNPs of MNPs@Fc, MNPs@AQ and MNPs@MB were characterized by square wave voltammetry (SWV) with their redox intensity of 0.64 ± 0.10 µA, 23.25 ± 0.73 µA and 0.48 ± 0.13 µA, respectively. In addition, the binding efficiency of adsorption between the MNPs and IgG was up to 78%, evidenced by SDS-PAGE gel analysis. This facile method offered a versatile and effective way to functionalize MNPs, combining redox and biological properties for potential applications in disease diagnosis and point-of-care diagnostics.
磁性纳米颗粒（MNPs）在广泛的应用中具有巨大潜力，然而，MNPs的表面修饰或生物共轭常常导致其聚集和不稳定。为了解决这个问题，我们提出了一种简便的方法，即使用聚烯丙胺盐酸盐（PAH）和聚苯乙烯磺酸钠盐（PSS）的层层（LbL）涂层技术，以维持MNPs的分散稳定性和功能。通过结合氧化还原探针（二茂铁（Fc）、蒽醌（AQ）或单羧甲基亚甲基蓝（MB））和生物探针（IgG），这种方法使我们能够开发出功能强大的MNPs用于电化学生物传感器。在有机溶剂中，氧化还原分子有效地锚定在MNPs上，而在分散于高离子强度溶液（如磷酸盐缓冲盐水）之前，这种功能化的MNPs表面随后通过LbL涂层过程得到保护。并且聚电解质壳的外层允许生物分子在不进行化学交联的情况下附着到MNP表面。我们的结果表明，LbL涂层后的MNPs@Fc、MNP@AQ和MNP@MB的透射电镜尺寸分别为11.0±2.0nm、10.5±2.1nm和12.4±2.2nm，并且这些开发的MNPs@Fc、MNPs@AQ和MNPs@MB氧化还原MNPs通过方波伏安法（SWV）表征，其氧化还原强度分别为0.64±0.10μA、23.25±0.73μA和0.48±0.13μA。此外，SDS-PAGE凝胶分析证明，MNPs与IgG之间的吸附结合效率高达78%。这种简便的方法提供了一种通用且有效的功能化MNPs的方式，结合了氧化还原和生物学特性，可用于疾病诊断和即时诊断的潜在应用。
