Magnetic Resonance Signal‐Enhancing Self‐Assembled Coating for Endovascular Devices

Abstract

tor was submerged in a thermostated water bath and stirred at 250 rpm. After 20 min, the homogeneous mixture of methyl methacrylate, vinylcarbazole, the oxadiazole derivative (NDA), and the perylene was poured into the reactor and stirred vigorously. The mixture was allowed to polymerize at 70 C for 7 h. Sodium bicarbonate and sodium persulfate were dissolved in water and added to the reaction mixture. The product was filtered and washed with DDI water. A standard recipe for emulsion copolymerization is shown in Table 1. Fabrication and Characterization of EL Devices:The indium tin oxide (ITO)-coated glass substrates (10 X cm ±2 ) were first patterned, and then cleaned according to the RCA procedure [24] (utilizing H 2 O/H 2 O 2 /NH 3 , 10:2:0.6, 55±60 C, 75 min). A thin polymer film was formed on the patterned ITO glass plate by spin-coating 10 wt.-% of an ELC colloidal dispersion in a 1 wt.-% poly(vinyl alcohol) (PVA)/ DDI water solution followed by drying under a vacuum for 6 h. The aluminum cathode was deposited on top of the polymer layer by thermal evaporation in a bell jar under a vacuum (<10 ±6 torr). The LED was thus a sandwich of ITO/ELC/Al with an active area of approximately 0.785 mm 2 . The LED was characterized by its current±voltage (I±V) and luminescence±voltage (L±V) characteristics in a computerized set-up consisting of a Newport 818SL photodetector, Keithley 238 multimeter, and Newport 835 optical powermeter.Surface Characterization of ELCs in LEDs: Phase imaging of the sample was performed in air by tapping-mode atomic force microscope using a Nanoscope III (Digital Instruments) equipped with a ªGº scanning head. Single-beam uncoated silicon cantilevers were used (125 nm length, type TESP, Digital Instruments). Optimal imaging conditions were achieved at drive frequencies around 270 kHz, a drive amplitude of 300 mV, and scan rate of 0.5 Hz. The EL devices for AFM observation were prepared by spin-coating several drops of ELC/DDI water dispersions onto an ITO-coated glass and drying under a vacuum for 10 h.

In vivo Cellular Uptake, Degradation, and Biocompatibility of Polyelectrolyte Microcapsules

“…Degradable polyelectrolyte microcapsules made of polypeptides and/-or polysaccharides were reported recently. [9,10] As polyelecrolyte multilayers on planar substrates start to emerge as multifunctional delivery platforms for implants, e.g., drug eluting stents or dental implants, [11][12][13][14][15][16][17][18][19][20] the potential of polyelectrolyte microcapsules as drug delivery systems could increase. [6,21] Polyelectrolyte microcapsules have the advantages of mild preparation conditions, multifunctionality, and the capacity to encapsulate large amounts of material.…”

Enhancement of Magnetic Resonance Imaging with Metasurfaces

“…Comprehensive work has shown that it is possible to reduce scanning time with the help of parallel imaging methods [16,17], that a substantial improvement in the SNR is available through multi-channel coils [18], and that larger area can be examined using traveling-wave technique [19,20]. The second approach is based on the idea to employ special contrast agents [21] locally enhancing the magnetic field, such as rare-earth magnetic atoms [22] and magnetic nanoparticles [23]. The third approach relies on special additional pads placed near the object.…”

Dendrimer‐Functionalized Shell‐crosslinked Iron Oxide Nanoparticles for In‐Vivo Magnetic Resonance Imaging of Tumors

“…[22] However, because of the large amount of carboxy groups on the dendrimer surface, the Fe 3 O 4 NPs modified with FA do not show specific binding to the FAR-expressing cells in vitro. In a previous work, it has been shown that Fe 3 O 4 NPs modified through an approach that combines a layer-by-layer (LbL) self-assembly technique [23][24][25][26][27][28][29][30][31][32][33][34] and dendrimer chemistry [18][19][20] can specifically target tumor cells overexpressing FAR in vitro. [35] In these studies, a bilayer composed of polystyrene sulfonate sodium salt (PSS) and FAand FI (fluorescein isothiocyanate)-functionalized PAMAM dendrimers of generation 5 (G5.NH 2 -FI-FA) were assembled onto Fe 3 O 4 NPs through electrostatic LbL assembly, followed by acetylation of the remaining surface amine groups of the assembled G5 dendrimers.…”