Noam Tal

Bio: Noam Tal is an academic researcher from Hebrew University of Jerusalem. The author has contributed to research in topics: Coating & Anodic stripping voltammetry. The author has an hindex of 11, co-authored 17 publications receiving 289 citations.

Poly(methyl methacrylate) grafting onto stainless steel surfaces: application to drug-eluting stents.

Abstract: Drug-eluting stents (DESs) have been associated with adverse clinical effects. Moreover, recent publications have shown that the coating of DESs suffers from defects. The purpose of this contribution is to examine a three-step process for surface modification as a means of improving the durability of DESs. In the first step, 4-(2-bromoethyl)benzenediazonium tetrafluoroborate was electrografted onto a stainless steel (SS) stent. X-ray photoelectron spectroscopy (XPS) of the modified stent confirmed the formation of the organic layer. In the second step, methyl methacrylate was polymerized onto the grafted surface by atom-transfer radical polymerization. XPS, electrochemical impedance spectroscopy, and contact-angle measurements were used to characterize the polymer brushes. The last step involved spray-coating of the stent with a drug-in-polymer matrix [poly(n-butyl methacrylate)/poly(ethylene-co-vinyl acetate) + paclitaxel]. Scanning electron microscopy confirmed the considerably improved durability of th...

Electrochemical Determination of Low Levels of Uranyl by a Vibrating Gold Microelectrode

Abstract: In this work we report the sensitive electroanalytical detection of uranium(VI) in aqueous solutions. Uranium commonly exists in aqueous solutions in the form of its oxo ion, uranyl (UVIO22+). The detection of uranyl has been accomplished by us through its deposition upon reduction by two electrons to the insoluble UO2 using a bare disk gold macroelectrode and anodic stripping voltammetry (ASV). This gave an unsatisfactory detection limit of ca. 1 × 10–5 M uranyl. Moreover, the evolution of hydrogen bubbles blocked the electrode surface as a result of water reduction at negative deposition potential (−0.7 V vs Ag/AgCl). The application of a 25 μm diameter Au microwire electrode on which UO2 precipitated at negative potential (−1.2 V) improved substantially the detection limit. Further improvement was accomplished by vibrating the microwire working electrode, which increased the amounts of UO2 deposition due to decreasing the diffusion layer. The effect of the vibrating amplitude and frequency on the elect...

Modified conductive surfaces having active substances attached thereto and uses thereof

Abstract: Novel processes for coating metal surfaces and/or for attaching active substances to metal surfaces, objects having coated metal surfaces and/or active substances attached thereto and uses thereof in the preparation of implantable devices are disclosed.

Electropolymerized tricopolymer based on N-pyrrole derivatives as a primer coating for improving the performance of a drug-eluting stent.

Abstract: The coating of medical implants by polymeric films aims at increasing their biocompatibility as well as providing a durable matrix for the controlled release of a drug. In many cases, the coating is divided into a primer layer, which bridges between the medical implant and the drug-eluting matrix. The primer coating must be very carefully designed in order to provide optimal interactions with the surface of the medical implant and the outer layer. Here we present a simple and versatile approach for designing the primer layer based on electropolymerization of a carefully chosen blend of three different pyrrole derivatives: N-methylpyrrole (N-me), N-(2-carboxyethyl)pyrrole (PPA), and the butyl ester of N-(2-carboxyethyl)pyrrole (BuOPy). The composition and physical properties of the primer layer were studied in detail by atomic force microscopy (AFM) and a nano scratch tester. The latter provides the in-depth analysis of the adhesion and viscoelasticity of the coating. AFM phase imaging reveals a uniform distribution of the three monomers forming rough morphology. This primer layer significantly improved the morphology, stability, and paclitaxel release profile of a paclitaxel-eluting matrix based on methyl and lauryl methacrylates.

Electrografting: a powerful method for surface modification

Abstract: Electrografting refers to the electrochemical reaction that permits organic layers to be attached to solid conducting substrates. This definition can be extended to reactions involving an electron transfer between the substrate to be modified and the reagent, but also to examples where a reducing or oxidizing reagent is added to produce the reactive species. These methods are interesting as they provide a real bond between the surface and the organic layer. Electrografting applies to a variety of substrates including carbon, metals and their oxides, but also dielectrics such as polymers. Since the 1980s several methods have been developed, either by reduction or oxidation, and some of them have reached an industrial stage. This critical review describes the methods that are used for electrografting, their mechanism, the formation and growth of the layers as well as their applications (742 references).

Aryl diazonium salts: a new class of coupling agents for bonding polymers, biomacromolecules and nanoparticles to surfaces

Abstract: This critical review summarizes existing knowledge on the use of diazonium salts as a new generation of surface modifiers and coupling agents for binding synthetic polymers, biomacromolecules, and nanoparticles to surfaces. Polymer grafts can be directly grown at surfaces through the so-called grafting from approaches based on several polymerization methods but can also be pre-formed in solution and then grafted to surfaces through grafting onto strategies including “click” reactions. Several routes are also described for binding biomacromolecules through aryl layers in view of developing biosensors and protein arrays, while the use of aryl diazonium coupling agents is extended to the attachment of nanoparticles. Patents and industrial applications of the surface chemistry of diazonium compounds are covered. This review stresses the paramount role of aryl diazonium coupling agents in adhesion, surface and materials sciences (114 references).

Drug delivery medical device

Abstract: Provided is a coated implantable medical device, comprising: a substrate; and a coating disposed on said substrate, wherein said coating comprises at least one polymer and at least one pharmaceutical agent in a therapeutically desirable morphology and/or at least one active biological agent and optionally, one or more pharmaceutical carrying agents; wherein substantially all of pharmaceutical agent and/or active biological agent remains within said coating and on said substrate until the implantable device is deployed at an intervention site inside the body of a subject and wherein upon deployment of said medical device in the body of said subject a portion of said pharmaceutical agent and/or active biological agent is delivered at said intervention site along with at least a portion of said polymer and/or a at least a portion of said pharmaceutical carrying agents.