{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,15]],"date-time":"2025-10-15T10:11:17Z","timestamp":1760523077391,"version":"build-2065373602"},"reference-count":36,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2013,7,3]],"date-time":"2013-07-03T00:00:00Z","timestamp":1372809600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/3.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>We demonstrate the possibility of using a radio-frequency transverse susceptibility (TS) technique based on a sensitive self-resonant tunnel-diode oscillator as a biosensor for detection of cancer cells that have taken up magnetic nanoparticles. This technique can detect changes in frequency on the order of 10 Hz in 10 MHz. Therefore, a small sample of cells that have taken up nanoparticles when placed inside the sample space of the TS probe can yield a signal characteristic of the magnetic nanoparticles. As a proof of the concept, Fe3O4 nanoparticles coated with Au (mean size ~60 nm) were synthesized using a micellar method and these nanoparticles were introduced to the medium at different concentrations of 0.05, 0.1, 0.5, and 1 mg\/mL buffer, where they were taken up by human embryonic kidney (HEK) cells via phagocytosis. While the highest concentration of  Au-Fe3O4 nanoparticles (1 mg\/mL) was found to give the strongest TS signal, it is notable that the TS signal of the nanoparticles could still be detected at concentrations as low  as 0.1 mg\/mL.<\/jats:p>","DOI":"10.3390\/s130708490","type":"journal-article","created":{"date-parts":[[2013,7,3]],"date-time":"2013-07-03T16:39:47Z","timestamp":1372869587000},"page":"8490-8500","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":9,"title":["Transverse Susceptibility as a Biosensor for Detection of  Au-Fe3O4 Nanoparticle-Embedded Human Embryonic  Kidney Cells"],"prefix":"10.3390","volume":"13","author":[{"given":"Natalie","family":"Huls","sequence":"first","affiliation":[{"name":"Department of Physics, University of South Florida, Tampa, FL 33620, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Manh-Huong","family":"Phan","sequence":"additional","affiliation":[{"name":"Department of Physics, University of South Florida, Tampa, FL 33620, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Arun","family":"Kumar","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine, University of South Florida, Tampa, FL 33620, USA"},{"name":"Department of Medical Laboratory Sciences, University of Delaware, Newark, DE 19716, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Subhra","family":"Mohapatra","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine, University of South Florida, Tampa, FL 33620, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shyam","family":"Mohapatra","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine, University of South Florida, Tampa, FL 33620, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Pritish","family":"Mukherjee","sequence":"additional","affiliation":[{"name":"Department of Physics, University of South Florida, Tampa, FL 33620, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hariharan","family":"Srikanth","sequence":"additional","affiliation":[{"name":"Department of Physics, University of South Florida, Tampa, FL 33620, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2013,7,3]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"R167","DOI":"10.1088\/0022-3727\/36\/13\/201","article-title":"Applications of magnetic nanoparticles in biomedicine","volume":"36","author":"Pankhurst","year":"2003","journal-title":"J. Phys. D: Appl. Phys."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"224002","DOI":"10.1088\/0022-3727\/42\/22\/224002","article-title":"Progress in the preparation of magnetic nanoparticles for applications in biomedicine","volume":"42","author":"Roca","year":"2009","journal-title":"J. Phys. D: Appl. Phys."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1401","DOI":"10.2217\/nnm.10.114","article-title":"Magnetic nanoparticles in biomedicine: synthesis, functionalization and applications","volume":"5","author":"Reynolds","year":"2010","journal-title":"Nanomedicine"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1252","DOI":"10.1016\/j.addr.2008.03.018","article-title":"Magnetic nanoparticles in MR imaging and drug delivery","volume":"60","author":"Sun","year":"2008","journal-title":"Adv. Drug. Deliv. Rev."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"977","DOI":"10.1007\/s11517-010-0649-3","article-title":"Magnetic biosensor technologies for medical applications: a review","volume":"48","author":"Llandro","year":"2010","journal-title":"Med. Biol. Eng. Comput."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"66","DOI":"10.1109\/TNB.2003.820277","article-title":"Surface-modified superparamagnetic nanoparticles for drug delivery: preparation, characterization, and cytotoxicity studies","volume":"3","author":"Gupta","year":"2004","journal-title":"IEEE Trans. Nanobioscience"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"3995","DOI":"10.1016\/j.biomaterials.2004.10.012","article-title":"Synthesis and surface engineering of iron oxide nanoparticles for biomedical applications","volume":"26","author":"Gupta","year":"2005","journal-title":"Biomaterials"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"821","DOI":"10.1002\/pi.2251","article-title":"Monodisperse magnetic nanoparticles for biomedical applications","volume":"56","author":"Xu","year":"2007","journal-title":"Polym. Int."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"583","DOI":"10.1002\/wnan.51","article-title":"Monodisperse magnetic nanoparticles for biodetection, imaging, and drug delivery: a versatile and evolving technology","volume":"1","author":"Dave","year":"2009","journal-title":"Nanobiotech."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"455","DOI":"10.1016\/j.tibtech.2004.06.006","article-title":"Magnetoresistive-based biosensors and biochips","volume":"22","author":"Graham","year":"2004","journal-title":"Trends in Biotech."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"6581","DOI":"10.1021\/ac0509049","article-title":"Giant Magnetoresistive Sensors and Superparamagnetic Nanoparticles: A Chip-Scale Detection Strategy for Immunosorbent Assays","volume":"77","author":"Millen","year":"2005","journal-title":"Anal. Chem."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"253901","DOI":"10.1063\/1.1952582","article-title":"In situ detection of single micron-sized magnetic beads using magnetic tunnel junction sensors","volume":"86","author":"Shen","year":"2005","journal-title":"Appl. Phys. Lett."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1687","DOI":"10.1109\/TMAG.2008.920962","article-title":"Advances in GMR biosensors with magnetic nanoparticle tags: review and outlook","volume":"44","author":"Wang","year":"2008","journal-title":"IEEE Trans. Magn."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"218","DOI":"10.1016\/j.mimet.2006.08.004","article-title":"Magnetic biosensor for the detection of Yersinia pestis","volume":"68","author":"Meyer","year":"2007","journal-title":"J. Microbio. Method."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"7785","DOI":"10.3390\/s91007785","article-title":"Resonant magnetic field sensors based on MEMS technology","volume":"9","author":"Manjarrez","year":"2009","journal-title":"Sensors"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"375","DOI":"10.1016\/S0304-8853(02)00561-9","article-title":"Development of amorphous wire type MI sensors for automobile use","volume":"249","author":"Honkura","year":"2002","journal-title":"J. Magn. Magn. Mater."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1318","DOI":"10.1016\/j.jmmm.2004.11.427","article-title":"A design of highly sensitive GMI sensor","volume":"290\u2013291","author":"Yabukami","year":"2005","journal-title":"J. Magn. Magn. Mater."},{"key":"ref_18","first-page":"515","article-title":"Novel magnetic field meter based on giant magneto-impedance (GMI) effect","volume":"65","author":"Nesteruk","year":"2006","journal-title":"Sen. Trans. Mag."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"323","DOI":"10.1016\/j.pmatsci.2007.05.003","article-title":"Giant magnetoimpedance materials: Fundamentals and applications","volume":"53","author":"Phan","year":"2008","journal-title":"Prog. Mater. Sci."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"3053","DOI":"10.1063\/1.1571957","article-title":"Giant-magnetoimpedance-based sensitive element as a model for biosensors","volume":"82","author":"Kurlyandskaya","year":"2003","journal-title":"Appl. Phys. Lett."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1611","DOI":"10.1016\/j.bios.2004.04.027","article-title":"Magnetic Dynabeads\u00ae detection by sensitive element based on giant magnetoimpedance","volume":"20","author":"Kurlyandskaya","year":"2005","journal-title":"Biosen. Bioelectron."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"143902","DOI":"10.1063\/1.2790370","article-title":"Magnetoimpedance biosensor for Fe3O4 nanoparticle intracellular uptake evaluation","volume":"91","author":"Kumar","year":"2007","journal-title":"Appl. Phys. Lett."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"043702","DOI":"10.1063\/1.3467833","article-title":"Giant magnetoimpedance-based microchannel system for quick and parallel genotyping of human papilloma virus type 16\/18","volume":"97","author":"Yang","year":"2010","journal-title":"Appl. Phys. Lett."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"659","DOI":"10.1016\/j.jmmm.2008.11.019","article-title":"Giant magnetoimpedance for biosensing: Advantages and shortcomings","volume":"321","author":"Kurlyandskaya","year":"2009","journal-title":"J. Magn. Magn. Mater."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"187","DOI":"10.1016\/j.jcis.2005.01.013","article-title":"Magnetite nanoparticles with tunable gold or silver shell","volume":"286","author":"Mandal","year":"2005","journal-title":"J. Coll. Int. Sci."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"07B511","DOI":"10.1063\/1.3068461","article-title":"Particle blocking and carrier fluid freezing effects on the magnetic properties of Fe3O4-based ferrofluids","volume":"105","author":"Morales","year":"2009","journal-title":"J. Appl. Phys."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"3520","DOI":"10.1063\/1.1599959","article-title":"Static and dynamic magnetic properties of spherical magnetite nanoparticles","volume":"94","author":"Goya","year":"2003","journal-title":"J. Appl. Phys."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1109\/TNANO.2004.840155","article-title":"Probing magnetic anisotropy and spin polarization in spintronic materials","volume":"4","author":"Poddar","year":"2005","journal-title":"IEEE Trans. Nanotech."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"3097","DOI":"10.1063\/1.1149892","article-title":"Radio-frequency impedance measurements using a tunnel-diode oscillator (TDO) technique","volume":"70","author":"Srikanth","year":"1999","journal-title":"Rev. Sci. Instrum."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"214409","DOI":"10.1103\/PhysRevB.68.214409","article-title":"In-plane and out-of-plane transverse susceptibility in close-packed arrays of monodisperse Fe nanoparticles","volume":"68","author":"Poddar","year":"2003","journal-title":"Phys. Rev. B"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"024420","DOI":"10.1103\/PhysRevB.74.024420","article-title":"Magnetic anisotropy in CrO2 and epitaxial CrO2\/Cr2O3 bilayers","volume":"74","author":"Frey","year":"2006","journal-title":"Phys. Rev. B"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"063901","DOI":"10.1063\/1.2977592","article-title":"Transverse susceptibility study of the effect of varying dipolar interactions on anisotropy peaks in a three-dimensional assembly of soft ferrite nanoparticles","volume":"104","author":"Poddar","year":"2008","journal-title":"J. Appl. Phys."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"024406","DOI":"10.1103\/PhysRevB.83.024406","article-title":"Transverse susceptibility as a probe of the magnetocrystalline anisotropy driven phase transition in Pr0.5Sr0.5CoO3","volume":"83","author":"Frey","year":"2011","journal-title":"Phys. Rev. B"},{"key":"ref_34","first-page":"215","article-title":"The reversible susceptibility tensor of the Stoner-Wohlfarth model","volume":"6A","author":"Aharoni","year":"1957","journal-title":"Bull. Res. Counc. Isr. Sect. A: Math. Phys. Chem."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"276","DOI":"10.1063\/1.1428626","article-title":"Effect of the second-order anistropy constant on the transverse susceptibility of uniaxial ferromagnets","volume":"80","author":"Spinu","year":"2002","journal-title":"Appl. Phys. Lett."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"2129","DOI":"10.1016\/j.jmmm.2009.01.019","article-title":"Magnetic measurements of suspended functionalised ferromagnetic beads under DC applied fields","volume":"321","author":"Llandro","year":"2009","journal-title":"J. Magn. Magn. Mater."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/13\/7\/8490\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T21:47:42Z","timestamp":1760219262000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/13\/7\/8490"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2013,7,3]]},"references-count":36,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2013,7]]}},"alternative-id":["s130708490"],"URL":"https:\/\/doi.org\/10.3390\/s130708490","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2013,7,3]]}}}