title: Maghemite, silver, ceragenin conjugate particles for selective binding and contrast of bacteria.
abstract: New synthesis techniques are providing increasing control over many inorganic nanoparticle characteristics, facilitating the creation of new multifunctional theranostics. This report proposes the synthesis and testing of a combination nanoparticle comprised of a maghemite core for enhanced T2 MRI contrast diagnostics, a colloidal silver shell acting as an antimicrobial and therapeutic vehicle, and a ceragenin (CSA-124) surfactant providing microbial adhesion. A polyacrylic acid functionalized maghemite nanoparticle is synthesized by a high temperature organic phase reduction followed by thiol functionalization and gold cluster seeding. A silver shell is formed through AgNO3 reduction, and an oriented monolayer of the thiolated ceragenin, is bound through a self-assembly process. The process and products are characterized throughout synthesis through TEM, DLS, FT-IR, UV-Vis, ICP-OES, HPLC-ESI-TOF-MS, DC magnetization and susceptibility, X-ray diffraction, and in vitro MRI. Synthesized Diagnostic Antimicrobial Nanoparticles (DANs) were found to have a spherical morphology with a diameter of 32.47±1.83 nm, hydrodynamic diameter of 53.05±1.20 nm, maximum magnetic moment of 12 emu/g NP (54 emu/g Fe) with little variation due to temperature, and are predominantly paramagnetic. In vitro MRI studies show that DANs contrast well at concentrations as low as 9 ppm, and successfully adhere to Staphylococcus aureus. DAN MIC was determined to be approximately 12 ppm and 24 ppm against S. aureus and Escherichia coli respectively.
authors.affiliation: Department of Biological and Agricultural Engineering, Louisiana State University and Agricultural Center, 149 E. B. Doran, Baton Rouge, LA 70803, USA. Electronic address: mhoppe4@lsu.edu.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Hoppens
authors.forename: Zaanan E W
authors.initials: ZE
authors.lastname: Wheeler
authors.forename: Ammar T
authors.initials: AT
authors.lastname: Qureshi
authors.forename: Katie
authors.initials: K
authors.lastname: Hogan
authors.forename: Ashleigh
authors.initials: A
authors.lastname: Wright
authors.forename: George G
authors.initials: GG
authors.lastname: Stanley
authors.forename: David
authors.initials: D
authors.lastname: Young
authors.forename: Paul
authors.initials: P
authors.lastname: Savage
authors.forename: Daniel
authors.initials: D
authors.lastname: Hayes
mesh_terms: D001419:Bacteria / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D005290:Ferric Compounds / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D012834:Silver / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D013256:Steroids / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D005290:Ferric Compounds; D013256:Steroids; C000499:ferric oxide; D012834:Silver
keywords: ACN; Antimicrobial; CSA; Ceragenin; DL-Dithiothreitol; DLS; DTT; ESI-TOF-MS; HPC; HPLC; ICP-OES; MNP; MRI; MRI contrast; Maghemite; NP; PAA; Silver nanoparticle; TEM; Theranostic; acetonitrile; cationic steroidal antimicrobial, aka ceragenins; dynamic light scattering; electrospray ionization -time of flight-mass spectrometer; high precision liquid chromatography; hyroxypropyl cellulose; inductively coupled plasma optical emission spectrometry; magnetic nanoparticle; magnetic resonance imaging; nanoparticle; polyacrylic acid; transmission electron microscopy