Aging phenomena in ferrofluids suitable for magnetic biosensor applications
2007 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 101, no 2, 023911- p.Article in journal (Refereed) Published
Agingphenomena were investigated in three different ferrofluids containing submicron sizedmagnetic beads consisting of a cluster of iron oxide nanoparticlesembedded in a dextrane matrix with primary amine groups onthe surface (one fresh sample and one sample aged duringthree months) and with a plain surface (only dextrane onthe surface, aged for three months), suitable for magnetic biosensorapplications. The main characterization technique used was measurement of thefrequency dependent complex magnetization using a superconducting quantum interference device.The experimental factors considered were the effect of ultrasonication, temperature,dc bias magnetic field, and addition of sodium dodecyl sulphatesurfactant. The stability against aging was found to depend stronglyon the bead surface, and the reproducibility of a refreshingprocedure involving addition of surfactant in combination with ultrasonication wasshown to be low. Aggregation was shown to be stronglyaffected by the presence of even a small bias magneticfield. Applying a dc bias field caused the formation ofmore or less stable chainlike aggregates with various lengths.
Place, publisher, year, edition, pages
2007. Vol. 101, no 2, 023911- p.
magnetic fluids, ageing, magnetic particles, iron compounds, nanoparticles, magnetic sensors, magnetisation, surfactants, aggregation, nanobiotechnology
Engineering and Technology Physical Sciences
IdentifiersURN: urn:nbn:se:uu:diva-98018DOI: 10.1063/1.2424522ISI: 000243890800083OAI: oai:DiVA.org:uu-98018DiVA: diva2:173175