Nur Aji Wibowo, Dani Muhammad Hariyanto, Zurnansyah, Mahardika Yoga Darmawan, Harlina Ardiyanti, Nurul Imani Istiqomah, Kohji Nakamura, Edi Suharyadi
For the development of green magnetic-based immunoassay devices, the rapid and reliable assay method of eco-friendly magnetic labels with a lower energy requirement is vital. This work proposes a green-synthesized Fe3O4@Ag magnetic label assay system using GMR chips and a simple microcontroller-based data acquisition tool. Optical analysis shows the successful synthesis of Fe3O4@Ag with the assistance of Moringa oleifera (MO) extract as a reducing and stabilizing agent. Meanwhile, according to characterization, MO-assisted green-synthesized Fe3O4@Ag nanocomposites feature cubic inverse spinel structures and ferromagnetic characteristics that possess multi-domain structures. The sensor system generates an intense signal, varying from tens to hundreds of millivolts, allowing for its detection using a simple microcontroller system. The sensor exhibits a stable and reliable response to the increase in the concentration of Fe3O4@Ag nanocomposite, even though it is subjected to weak magnetic field induction. Furthermore, the introduction of Ag on the surface of Fe3O4 nanoparticles succeeded in optimizing the detection features, as evidenced by the lower limit of detection compared to detecting the bare Fe3O4. The GMR-based sensor, featuring a simple microcontroller structure and an eco-friendly Fe3O4@Ag nanocomposite as a magnetic label, exhibits significant potential as a rapid and reliable green biosensor that is power-efficient. © 2024 The Electrochemical Society (“ECS”). Published on behalf of ECS by IOP Publishing Limited. All rights, including for text and data mining, AI training, and similar technologies, are reserved.
Department of Physics, Universitas Kristen Satya Wacana, Salatiga, Indonesia; Department of Physics, Universitas Gadjah Mada, Yogyakarta, Indonesia; Department of Physics, Institut Teknologi Sumatera, Lampung, Indonesia; Graduate School of Engineering, Mie University, Japan