Green Synthesis Nanoparticles Fe3O4 from Natural Iron Sand Lampung for Magnetic Biosensor Applications Department of Physics, Faculty of Science, Sumatera Institute of Technology, South Lampung 35365, Indonesia Abstract Biosensors are sensors used to detect the presence of biomaterials, such as enzymes, proteins, various types of dangerous substances, viruses, formaldehyde, and various other types of diseases. One type of sensor used for biosensors is a magnetic sensor. In this research, we use biosensors based on giant magnetoresistance (GMR) and tunneling magnetoresistance (TMR) sensors. These GMR and TMR sensors work based on changes in resistance or output voltage in the presence of an external magnetic field around them. The magnetic material that will be used as a source of external magnetic field induction is green synthesis Fe3O4 magnetic material from iron sand in Lampung, especially in the South Lampung district. The Fe3O4 binds with biomaterials by using ligands. The biomaterial binding ligands used consist of polyethylene glycol (PEG), dextran, and chitosan. The measurement results show that the GMR and TMR sensors can detect the presence of Fe3O4. The X-ray diffraction and vibrating sample magnetometer characterization show that polycrystal magnetite phase and superparamagnetic behavior are formed. The sensor output signal changes as a function of time with increasing Fe3O4 mass. Furthermore, the sensor signal also changes as ligands and biomaterial are attached to Fe3O4. These changes originated from the stray field of Fe3O4 that can influence the Our results indicate that Fe3O4 magnetic material from iron sand in Lampung is potentially used for biosensor application. Keywords: Green synthesis Fe3O4, Iron Sand, GMR and TMR sensors, Biosensor applications Topic: Physics and Applied Physics |
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