Nur Aji Wibowo, Samarthya Lykamanuella, Dera Anastasya Putri, Lorin Parqista Lase, Agi Karunia Putra, Dewi K.A. Kusumahastuti, Demas Sabatino, Vector Stephen Dewangga, Omry Tri Asmara Adi, Pinaka Elda Swastika, Candra Kurniawan, Edi Suharyadi, Budi Purnama, Riyan Mendonsa
The requirement for highly sensitive bovine serum albumin (BSA) assays characterized by low noise levels and low bias magnetic fields is critical for microalbuminuria screening purposes. This research presents a novel, highly sensitive approach for the BSA assay by integrating a magnetic tunnel junction sensor with an ultra-small iron oxide/silver magnetic label, biosynthesized utilizing Aloe vera extract. The magnetic label demonstrates soft magnetic properties, exhibiting a saturation magnetization of 30 emu/g, a magnetic remanence of 5.2 emu/g, and a coercivity of 69 Oe, while presenting a quasi-spherical morphology with a tiny size of (6.9 ± 1.06) nm. The preliminary in vivo hematological assessment results convey a first glimpse of the potential biocompatibility of biosynthesized iron oxide/silver nanoparticles. The study demonstrates that magnetic field modification enhances sensor performance, yielding increased sensitivity and a reduced limit of detection (LoD) for accurate quantification of BSA. The sensor has remarkable sensitivity for BSA monitoring, attaining an LoD of 1.8 μM at a low bias magnetic field of 2.8 Oe. The proposed sensor system demonstrates an insignificant relative standard deviation ranging from 0.006% to 1.6%. It preserves a stable output voltage for 60 s without digital signal processing, signifying its low noise levels and excellent precision and reproducibility. © 2026 Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
Dept. of Physics, Universitas Kristen Satya Wacana, Salatiga, 50711, Indonesia; Dept. of Physics Education, Universitas Kristen Satya Wacana, Salatiga, 50711, Indonesia; Dept. of Chemistry, Universitas Kristen Satya Wacana, Salatiga, 50711, Indonesia; Dept. of Electronics and Computer Engineering, Universitas Kristen Satya Wacana, Salatiga, 50711, Indonesia; Dept. of Medical Laboratory Technology, Sekolah Tinggi Ilmu Kesehatan Nasional, Sukoharjo, 57552, Indonesia; Dept. of Physics Education, Universitas Negeri Yogyakarta, 55281, Indonesia; Research Center for Energy Materials, National Research and Innovation Agency (BRIN), KST BJ Habibie Office Area, Selatan, Tangerang, 15314, Indonesia; Dept. of Physics, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia; Dept. of Physics, Universitas Sebelas Maret, Surakarta, 57126, Indonesia; Dept. of Electrical and Computer Engineering, University of Minnesota, Minneapolis, 55455, MN, United States
