Iron oxide nanoparticles (IONPs) have been studied extensively for biomedical applications, which require that they be aqueous-stable at physiological pH. The structures of some of these buffers, however, may also allow for binding to surface iron, thus potentially exchanging with functionally relevant ligands, and altering the desired properties of the nanoparticles. We report here on the interactions of five common biologically relevant buffers (MES, MOPS, phosphate, HEPES, and Tris) with iron oxide nanoparticles through spectroscopic studies.
View Article and Find Full Text PDFThe excellent performance of functionalized iron oxide nanoparticles (IONPs) in nanomaterial and biomedical applications often relies on achieving the attachment of ligands to the iron oxide surface both in sufficient number and with proper orientation. Toward this end, we determine relationships between the ligand chemical structure and surface binding on magnetic IONPs for a series of related benzoic acid and catechol derivatives. Ligand exchange was used to introduce the model ligands, and the resultant nanoparticles were characterized using Fourier transform infrared-attenuated internal reflectance spectroscopy, transmission electron microscopy, and nanoparticle solubility behavior.
View Article and Find Full Text PDFWe describe a simple, rapid methodology for the synthesis of water-stable iron oxide nanoparticles (IONPs) compatible with a variety of aqueous buffers, based on mechanochemical milling exchange of covalently bound surface ligands on pre-fabricated oleic acid-protected IONPs. Application of milling for IONP ligand exchange eliminates steps required for transforming hydrophobic into negatively charged, water-soluble superparamagnetic IONPs.
View Article and Find Full Text PDFGlass surfaces were modified with a combination of dyes and reagents to allow for the potential simultaneous recording of a detailed fingerprint and the detection of the explosive urea nitrate (UN), as a proof of principle of surface modification for simultaneous linking of identity to manipulation of explosives. By coating microscope slides with 9,10-diphenylanthracene (DPA), p-dimethylaminobenzaldehyde (p-DMAB) and p-dimethylaminocinnamaldehyde (p-DMAC), a colorimetric change was observed in the presence of UN, while revealing a fingerprint with enough resolution to isolate at least 10 minutiae. This is the first step in creating point-of-care devices capable of detecting low concentrations of explosives and drug metabolites and connecting them to a fingerprint.
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