Functional Polyelectrolyte Coatings on Polymeric and Magnetic Colloidal Particles for Antifouling and Non-Toxic Bioconjugate Nanoparticles

Computer Simulation Insight into the Adsorption and Diffusion of Polyelectrolytes on Oppositely Charged Surface

In the present work, by means of computer simulation, we studied the adsorption and diffusion of polyelectrolyte macromolecules on oppositely charged surfaces. We considered the surface coverage and the charge of the adsorbed layer depending on the ionization degree of the macromolecules and the charge of the surface and carried out a computer experiment on the polymer diffusion within the adsorbed layers, taking into account its strong dependency on the surface coverage and the macromolecular ionization degree. The different regimes were distinguished that provided maximal mobility of the polymer chains along with a high number of charged groups in the layer, which could be beneficial for the development of the functional coatings. The results were compared with those of previous experiments on the adsorption of polyelectrolyte layers that may be applied as biocidal renewable coatings that can reversibly desorb from the surface.

Ultrathin Nanostructured Films of Hyaluronic Acid and Functionalized β-Cyclodextrin Polymer Suppress Bacterial Infection and Capsular Formation of Medical Silicone Implants

A type of ultrathin films has been developed for suppressing capsule formation induced by medical silicone implants and hence reducing the inflammation response to such formation and the differentiation to myofibroblasts. The films were each fabricated from hyaluronic acid (HA) and modified β-cyclodextrin (Mod-β-CyD) polymer which was synthesized with a cyclodextrin with partially substituted quaternary amine. Ultrathin films comprising HA and Mod-β-CyD or poly(allylamine hydrochloride) (PAH) were fabricated by using a layer-by-layer dipping method. The electrostatic interactions produced from the functional groups of Mod-β-CyD and HA influenced the surface morphology, wettability, and bio-functional activity of the film. Notably, medical silicone implants coated with PAH/HA and Mod-β-CyD multilayers under a low pH condition exhibited excellent biocompatibility and antibiofilm and anti-inflammation properties. Implantation of these nanoscale film-coated silicones showed a reduced capsular thickness as well as reduced TGFβ-SMAD signaling, myofibroblast differentiation, biofilm formation, and inflammatory response levels. We expect our novel coating system to be considered a strong candidate for use in various medical implant applications in order to decrease implant-induced capsule formation.

Parallel Multichannel Assessment of Rotationally Manipulated Magnetic Nanoparticles

Background

Rotational manipulation of chains or clusters of magnetic nanoparticles (MNPs) offers a means for directed translation and payload delivery that should be explored for clinical use. Multiple MNP types are available, yet few studies have performed side-by-side comparisons to evaluate characteristics such as velocity, movement at a distance, and capacity for drug conveyance or dispersion.

Purpose

Our goal was to design, build, and study an electric device allowing simultaneous, multichannel testing (e.g., racing) of MNPs in response to a rotating magnetic field. We would then select the "best" MNP and use it with optimized device settings, to transport an unbound therapeutic agent.

Methods

A magnetomotive system was constructed, with a Helmholtz pair of coils on either side of a single perpendicular coil, on top of which was placed an acrylic tray having multiple parallel lanes. Five different MNPs were tested: graphene-coated cobalt MNPs (TurboBeads™), nickel nanorods, gold-iron alloy MNPs, gold-coated Fe3O4 MNPs, and uncoated Fe3O4 MNPs. Velocities were determined in response to varying magnetic field frequencies (5-200 Hz) and heights (0-18 cm). Velocities were normalized to account for minor lane differences. Doxorubicin was chosen as the therapeutic agent, assayed using a CLARIOstar Plus microplate reader.

Results

The MMS generated a maximal MNP velocity of 0.9 cm/s. All MNPs encountered a "critical" frequency at 20-30 Hz. Nickel nanorods had the optimal response based on tray height and were then shown to enable unbound doxorubicin dispersion along 10.5 cm in <30 sec.

Conclusion

A rotating magnetic field can be conveniently generated using a three-coil electromagnetic device, and used to induce rotational and translational movement of MNP aggregates over mesoscale distances. The responses of various MNPs can be compared side-by-side using multichannel acrylic trays to assess suitability for drug delivery, highlighting their potential for further in vivo applications.