Surface modification of substrates

The present invention is directed to a practically universal surface modification process and the materials thereby obtained. In general, the process includes initial epoxy modification of a substrate surface by attachment of an epoxy-containing polymer to the surface. Following attachment of the polymer, still-existing epoxy groups on the polymer may then cross-link the polymer to form a unified anchoring layer on the surface. Other epoxy groups in the anchoring layer, not utilized in forming the layer may be used to graft surface modifying materials to the surface. For instance, macromolecules, biomolecules, polymers, and polymerization initiators may be grafted to the surface via the anchoring layer

Surface modification of substrates

The present invention is directed to a practically universal surface modification process and the materials thereby obtained. In general, the process includes initial epoxy modification of a substrate surface by attachment of an epoxy-containing polymer to the surface. Following attachment of the polymer, still-existing epoxy groups on the polymer may then cross-link the polymer to form a unified anchoring layer on the surface. Other epoxy groups in the anchoring layer, not utilized in forming the layer may be used to graft surface modifying materials to the surface. For instance, macromolecules, biomolecules, polymers, and polymerization initiators may be grafted to the surface via the anchoring layer

Method of manufacturing ultrahydrophobic substrates

A process for modification of a substrate so as to form an ultrahydrophobic surface on the substrate is provided. Surface-modified substrates that can be formed according to the disclosed processes are also provided. The process includes attachment of a multitude of nano- and/or submicron-sized structures to a surface to provide increased surface roughness. In addition, the process includes grafting a hydrophobic material to the surface in order to decrease the surface energy and decrease wettability of the surface. The combination of increased surface roughness and decreased surface energy can provide an ultrahydrophobic surface on the treated substrate

Capillary-channeled polymeric fiber as solid phase extraction media

Solid phase extraction devices including a plurality of packed nominally aligned capillary-channeled polymeric fibers for use as stationary phase materials are disclosed. A plurality of fibers are packed together in a casing so as to provide good flow characteristics through the fibers and high surface area contact between a sample and the fibers. Different polymer compositions of the fibers permit the chemical tuning of the extraction process. The fibers can be physically or chemically derivatized to target specific analytes for separation from a test sample. Use of the fibers allows a wide range of liquid flow rates with very low backpressures. The fibers are easily packed into a micropipette tip or a conduit for use with a fluid flow device such as an aspirator or a pump. The devices can be used for isolation and pre-concentration of analytes from samples, for instance for proteins from buffer solutions or extraction of pollutants from remote locations

Ultrahydrophobic Substrates

Disclosed is a process for modification of a substrate so as to form an ultrahydrophobic surface on the substrate. Also disclosed are surface-modified substrates that can be formed according to the disclosed processes. The process includes attachment of a multitude of nano- and/or submicron-sized structures to a surface to provide increased surface roughness. In addition, the process includes grafting a hydrophobic material to the surface in order to decrease the surface energy and decrease wettability of the surface. The combination of increase surface roughness and decreased surface energy can provide an ultrahydrophobic surface on the treated substrate

In vivo imaging and biodistribution of multimodal polymeric nanoparticles delivered to the optic nerve

The use of nanoparticles for targeted delivery of therapeutic agents to sites of injury or disease in the central nervous system (CNS) holds great promise. However, the biodistribution of nanoparticles following in vivo administration is often unknown, and concerns have been raised regarding potential toxicity. Using poly(glycidyl methacrylate) (PGMA) nanoparticles coated with polyethylenimine (PEI) and containing superparamagnetic iron oxide nanoparticles as a magnetic resonance imaging (MRI) contrast agent and rhodamine B as a fluorophore, whole animal MRI and fluorescence analyses are used to demonstrate that these nanoparticles (NP) remain close to the site of injection into a partial injury of the optic nerve, a CNS white matter tract. In addition, some of these NP enter axons and are transported to parent neuronal somata. NP also remain in the eye following intravitreal injection, a non-injury model. Considerable infiltration of activated microglia/macrophages occurs in both models. Using magnetic concentration and fluorescence visualization of tissue homogenates, no dissemination of the NP into peripheral tissues is observed. Histopathological analysis reveals no toxicity in organs other than at the injection sites. Multifunctional nanoparticles may be a useful mechanism to deliver therapeutic agents to the injury site and somata of injured CNS neurons and thus may be of therapeutic value following brain or spinal cord trauma

Emerging Applications of Stimuli-responsive Polymer Materials

Responsive polymer materials can adapt to surrounding environments, regulate transport of ions and molecules, change wettability and adhesion of different species on external stimuli, or convert chemical and biochemical signals into optical, electrical, thermal and mechanical signals, and vice versa. These materials are playing an increasingly important part in a diverse range of applications, such as drug delivery, diagnostics, tissue engineering and \u27smart\u27 optical systems, as well as biosensors, microelectromechanical systems, coatings and textiles. We review recent advances and challenges in the developments towards applications of stimuli-responsive polymeric materials that are self-assembled from nanostructured building blocks. We also provide a critical outline of emerging developments

Multimodal Analysis of PEI-Mediated Endocytosis of Nanoparticles in Neural Cells

Polymer nanoparticles are widely used as a highly generalizable tool to entrap a range of different drugs for controlled or site-specific release. However, despite numerous studies examining the kinetics of controlled release, the biological behavior of such nanoparticles remains poorly understood, particularly with respect to endocytosis and intracellular trafficking. We synthesized polyethylenimine-decorated polymer nanospheres (<i>ca.</i> 100–250 nm) of the type commonly used for drug release and used correlated electron microscopy, fluorescence spectroscopy and microscopy, and relaxometry to track endocytosis in neural cells. These capabilities provide insight into how polyethylenimine mediates the entry of nanoparticles into neural cells and show that polymer nanosphere uptake involves three distinct steps, namely, plasma membrane attachment, fluid-phase as well as clathrin- and caveolin-independent endocytosis, and progressive accumulation in membrane-bound intracellular vesicles. These findings provide detailed insight into how the intracellular delivery of nanoparticles is mediated by polyethylenimine, which is presently the most commonly used nonviral gene transfer agent. This fundamental knowledge may also assist in the preparation of next-generation nonviral vectors

Multimodal Analysis of PEI-Mediated Endocytosis of Nanoparticles in Neural Cells

Polymer nanoparticles are widely used as a highly generalizable tool to entrap a range of different drugs for controlled or site-specific release. However, despite numerous studies examining the kinetics of controlled release, the biological behavior of such nanoparticles remains poorly understood, particularly with respect to endocytosis and intracellular trafficking. We synthesized polyethylenimine-decorated polymer nanospheres (<i>ca.</i> 100–250 nm) of the type commonly used for drug release and used correlated electron microscopy, fluorescence spectroscopy and microscopy, and relaxometry to track endocytosis in neural cells. These capabilities provide insight into how polyethylenimine mediates the entry of nanoparticles into neural cells and show that polymer nanosphere uptake involves three distinct steps, namely, plasma membrane attachment, fluid-phase as well as clathrin- and caveolin-independent endocytosis, and progressive accumulation in membrane-bound intracellular vesicles. These findings provide detailed insight into how the intracellular delivery of nanoparticles is mediated by polyethylenimine, which is presently the most commonly used nonviral gene transfer agent. This fundamental knowledge may also assist in the preparation of next-generation nonviral vectors