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Targeted Ultrasound Contrast Agents
Published in Martin G. Pomper, Juri G. Gelovani, Benjamin Tsui, Kathleen Gabrielson, Richard Wahl, S. Sam Gambhir, Jeff Bulte, Raymond Gibson, William C. Eckelman, Molecular Imaging in Oncology, 2008
Mark A. Borden, Paul A. Dayton
Coalescence can lead to large changes in microbubble size distribution during fabrication and storage and can also lead to embolism in vivo. Microbubble fusion can be inhibited by the presence of the shell, which requires fracture to allow the gas surfaces to come into contact. Addition of a hydrophilic polymer brush layer, such as that formed by grafted polyethylene glycol (PEG), can provide repulsive steric and osmotic forces that prevent microbubble shells from contact during a collision.
Plasma-initiated graft polymerization of carbon nanoparticles as nano-based drug delivery systems
Published in Biofouling, 2022
Tianchi Liu, Christopher Stradford, Ashwin Ambi, Daniel Centeno, Jasmine Roca, Thomas Cattabiani, Thomas J. Drwiega, Clive Li, Christian Traba
Plasma technology is often used to treat biofilms directly or to modify the surface of materials including polyethylene terephthalate (PET), titanium dioxide, fluorine-doped tin oxide, silicon, and silicone (Zelaya et al. 2012; Traba et al. 2013; Traba and Liang 2015b; Ambi et al. 2018a; Badiei et al. 2021). In this study a ‘grafting-from’ technique was applied to modify the surface of CNPs. Surface modification of CNPs using plasma-initiated graft polymerization is an innovative and attractive modification strategy for materials and CNPs (Polidor et al. 2020). The reaction process is easily controlled, eco-friendly, and safe for the operator (Traba and Liang 2015b). The plasma-initiated graft polymerization reaction generates a desired polymer brush layer (nanocoating) with a specific chemical composition which may possess different chemical properties from the materials to which they are bound (Traba and Liang 2015a; Ambi et al. 2018a).
Antifouling properties of layer by layer DNA coatings
Published in Biofouling, 2019
Guruprakash Subbiahdoss, Guanghong Zeng, Hüsnü Aslan, Jakob Ege Friis, Joseph Iruthayaraj, Alexander N. Zelikin, Rikke Louise Meyer
Polymer brush coatings are thin films of polymer chains that are anchored at one end to the substratum through covalent bonding or physical absorption. Polymer brush coatings or polymer layers have been at the center of a large number of proposed AF coatings. Cationic polymers with eg quaternary ammonium groups have been developed for contact-killing surfaces (Carmona-Ribeiro and de Melo Carrasco 2013; Li et al. 2011), but a drawback of this approach is that bacteria and proteins readily adsorb to these surfaces and neutralize their effect. Neutral or zwitterionic polymers do not attract bacteria, and highly hydrophilic polymers of this kind can bind water sufficiently strongly to create a steric barrier between the bacterial cell and the underlying material, even if the layer is only a few nanometers thick (Chen et al. 2010; Jeon et al. 1991; Banerjee et al. 2011). In addition to this effect, anionic polymers also repel bacteria through electrostatic repulsion due to the overall negative charge of the bacterial cell.
Anti-infection silver nanoparticle immobilized biomaterials facilitated by argon plasma grafting technology
Published in Biofouling, 2018
Ashwin Ambi, Nisharg Parikh, Carolina Vera, Krystal Burns, Naidel Montano, Leonard Sciorra, Jessica Epstein, Debing Zeng, Christian Traba
In order to better understand the physical properties of the anti-infection biomaterials, highly magnified SEM images of the modified biomaterials were taken and studied. In these images, grafted surfaces with densities of 48 μg cm−2 demonstrate uniform polymer brush coverage with no cross-linking (Figure 11A). However, as AgNPs were immobilized onto grafted surfaces, multiple attachment sites between polymer brushes and AgNPs are apparent and are indicated by ATR-FTIR peak shifts. The high stability of the anti-infection surfaces can therefore be explained by the multiple attachment sites between the platform and AgNPs resulting in cross-linked nanocoatings and is visualized by SEM (Figure 11B). When immobilized AgNP surfaces were further examined, multilayer cross-linked AgNP surfaces were constructed under the above experimental conditions (Figure 11C). AgNPs were uniformly distributed throughout the surface, as well as bound in between the polymer brushes in a multilayer fashion with minimal AgNP aggregation. This form of immobilization rather than the deposition of AgNPs specifically located at the surface of the modified material allows for an even distribution of AgNPs throughout the material and provides the appropriate concentration of AgNPs required for anti-infection activity, while maintaining the biocompatibility of the biomaterial.