Nonbiodegradable polymer coating based on N-(2-carboxyethyl)pyrrole (PPA) and Bu ester of PPA (BuOPy) were successfully electrodeposited on a stainless steel stent surface using cyclic voltammetry. Chem. compn. of the coating was examd. by XPS. Polymer stability was examd. by immersing the coated stent into 1:1 soln. of fetal calf serum:seline soln. up to 1 yr and implantation s.c. in mouse for 1 wk. Morphol. changes were then recorded by SEM. Paclitaxel loading was carried out by immersion into drug soln. and its release was detected by HPLC. The results show that thin (single micrometers), uniform coating with various morphol. and hydrophobicity can be created by electrochem. deposition. The polymer did not show significant histopathol. or morphol. changes in vitro and in vivo. The surface properties allow loading appropriate amts. of paclitaxel and release it slowly up to a month. [on SciFinder(R)]

The aim of this study is to locally deposit nanoparticles on an unbiased surface by electroless deposition (ED) using scanning electrochem. microscopy (SECM). We have developed an ED process that is based on the redn. of gold ions by hydroquinone (H2Q) and catalyzed by a metallic surface, such as palladium. One of the advantages of this system is the ability to drive the ED at pH 1-7. The metal ions were electrogenerated in a soln. consisting of H2Q and KCl by anodic dissoln. of a gold microelectrode. AuCl4- reacted with H2Q at the electrolyte/metallic interface to form benzoquinone and gold deposit. The ED was studied initially in bulk soln. contg. KCl, H2Q, and HAuCl4, and then by SECM. We found that the pH had a significant effect on the nature of the deposited gold and could be correlated with the kinetics of gold ions redn. by H2Q. Hence, either nanoparticles or much larger crystals could be formed, depending on the pH of the deposition soln. Time of deposition and H2Q concn. also affected the shape and d. of the deposition. [on SciFinder(R)]

This invention relates to medical devices having a matrix comprising a pharmaceutically active agent, the matrix being adhered to a surface of the medical device via an adherence to modulate a release of the pharmaceutically active agent. [on SciFinder(R)]

Articles-of-manuf. (for medical devices) comprising 1 aryl moiety electrochem. attached to the surface thereof are disclosed. Further disclosed herein are novel compds. comprising an aryl moiety and substituted by at least 2 diazonium moieties, which may optionally be used to the articles-of-manuf. Stents were electro-coated with tetrakis[(4-diazophenoxy)methyl]methane tetrafluoroborate. [on SciFinder(R)]

An approach for patterning surface with different structures in a single step is demonstrated. The approach is based on the construction of nondisk shape microelectrodes combined with the feedback mode of scanning electrochem. microscopy (SECM) for generating an anisotropic flux of electroactive species. The latter attains the shape of the microelectrode and imprints its shape upon reaction with the surface. The authors have demonstrated this approach in two model systems. The etching of GaAs using electrogenerated bromine resulted in the formation of etching structures imprinting the shape of the Pt microelectrode on the GaAs. The second system comprised the electrogeneration of silver ions from a silver microelectrode, which reacted with a copper surface causing the deposition of silver patterns matching the shape of the silver microelectrode. SECM tips with different shapes were constructed by different methods, including electron-beam lithog. [on SciFinder(R)]

The reactions between Ag+ and AuCl4- ions with 3 different CdTe systems, i.e., thermally evapd. thin CdTe films, CdTe nanoparticles (NPs) stabilized by thioglycolic acid (TGA), and 20 layers of these CdTe NPs embedded in poly(diallyldimethylammonium) chloride (CdTe-20lbl), were studied. AuCl4- oxidized the CdTe, in all studied systems, to form metallic Au. However, the kinetics of the reaction was substantially sluggish for the thin CdTe films than with the CdTe NPs systems. However, the reaction with Ag+ was rather complex, and the findings alluded to different reaction for each system. Although it is possible that a Ag-SR bond was formed between Ag+ and the thiol group of the TGA-stabilized NPs, cation exchange between Ag+ and Cd2+ is evidenced when these CdTe NPs were embedded in a polymer (CdTe-20lbl). Also, Ag+ reacted with thin CdTe films to form a ppt. consisting of Ag. The authors studied the reactions between locally generated Ag+ and AuCl4- and CdTe surfaces using scanning electrochem. microscopy (SECM). A flux of Ag and Au chloride ions was electrochem. generated from their resp. microelectrodes upon applying a pos. potential close to thin CdTe films and CdTe-20lbl. The flux of AuCl4- resulted in the local formation of Au NPs on the CdTe surface, whereas local quenching of CdTe-20lbl was achieved by the flux of Ag+ ions. Finally, the current transients recorded during the SECM expts. provided invaluable information regarding the reactions at the CdTe surface below the microelectrodes. [on SciFinder(R)]

The etching of thin Cu films by scanning electrochem. microscopy (SECM) was studied. It is not trivial that locally injected charge by an oxidized mediator will lead to dissoln. of Cu as the charge can easily be dissipated by lateral charge propagation. The authors studied the effect of different parameters, such as thickness of the Cu film and concn. of the mediator, on the efficiency of etching. The feedback current is the sum of 3 charge transfer contributions: diffusion of mediator species, chem. reaction on the surface and lateral charge propagation across the Cu film. The authors have introduced an approach for isolating the lateral contribution and studied the parameters affecting the fate of the locally injected charge. Etching becomes effective once the lateral contribution cannot dissipate the locally injected charge. This occurs as the concn. of the etchant increases or the film thickness decreases. Measuring the steady-state current above Cu films with different thickness, allowed estg. the p.d. across the Cu area underneath the tip. Driving local processes, such as etching, depends on creating a mechanism which maintains the injected charge focused. [on SciFinder(R)]

Two different types of nanoparticles dissolved in org. soln., Au stabilized by n-alkanethiols and CdSe/ZnS stabilized by n-alkaneamine, adhere preferentially to the ridges of latent fingerprints,. The gold deposits catalyze silver electroless deposition from "Silver Phys. Developer" (Ag-PD), an aq. soln. contg. silver colloids stabilized by cationic surfactants, to form dark impressions of the ridge details. The hydrophobic capped gold nanoparticles significantly improve the intensity and clarity of the developed prints compared with Ag-PD alone. Fingermarks treated with CdSe/ZnS nanoparticles can be viewed directly, due to their fluorescence under UV illumination. [on SciFinder(R)]

Two different types of nanoparticles dissolved in organic solution, gold stabilized by n-alkanethiols and CdSe/ZnS stabilized by n-alkane-amine, adhere preferentially to the ridges of latent fingerprints; the gold deposits catalyze silver electroless deposition from "Silver Physical Developer" (Ag-PD), an aqueous solution containing silver colloids stabilized by cationic surfactants, to form dark impressions of the ridge details; the hydrophobic capped gold nanoparticles significantly improve the intensity and clarity of the developed prints compared with Ag-PD alone; finger marks treated with CdSe/ZnS nanoparticles can be viewed directly, due to their fluorescence under UV illumination.[on SciFinder (R)]

Org. coatings based on N-(2-carboxyethyl)pyrrole (PPA) and a Bu ester of PPA (BuOPy) were deposited via electrochem. oxidn. The homo- and copolymers were electropolymd. on glassy C and stainless steel in MeCN using Bu4NBF4B as the electrolyte. The mechanism of deposition on stainless steel was studied by chronoamperometry and by the tapping and phase angle imaging modes of at. force microscopy. The electrochem. properties and growth of the films were studied by cyclic voltammetry. The compn. of the copolymers was detd. by reflection-absorption FTIR spectroscopy. While the hydrophilic monomer PPA undergoes progressive nucleation followed by instantaneous growth the hydrophobic BuOPy nucleates instantaneously. The rate of BuOPy electropolymn. was higher than that of PPA, and the resulting film was thicker yet fluffier. Copolymer films were enriched by BuOPy as compared with the electropolymn. soln., which is attributed to the faster rate of electropolymn. of BuOPy than PPA. [on SciFinder(R)]

Organic coatings based on N-(2-carboxyethyl)pyrrole (PPA) and a butyl ester of PPA (BuOPy) were deposited via electrochemical oxidation. The homo- and copolymers were electropolymerized on glassy carbon and stainless steel in acetonitrile using tetrabutylammonium tetrafluoraborate (Bu4NF4B) as the electrolyte. The mechanism of deposition on stainless steel was studied by chronoamperometry and by the tapping and phase angle imaging modes of atomic force microscopy. The electrochemical properties and growth of the films were investigated by cyclic voltammetry. The composition of the copolymers was determined by reflection-absorption Fourier transform infrared spectroscopy. We found that while the hydrophilic monomer PPA undergoes progressive nucleation followed by instantaneous growth the hydrophobic BuOPy nucleates instantaneously. The rate of BuOPy electropolymerization was higher than that of PPA, and the resulting film was thicker yet fluffier. Copolymer films were enriched by BuOPy as compared with the electropolymerization solution, which is attributed to the faster rate of electropolymerization of BuOPy than PPA.[on SciFinder (R)]

The purpose of this study was to examine chem., mech. and Paclitaxel release properties of the new coating onto the stainless steel coronary stents. Stainless steel coronary stents were coated with elec. polymerizable pyrrole deriv., applying cyclic voltammetry technique in a simple 3 electrode cell, while stent represented a working electrode. Resulted polymer coating were examd. by cyclic voltammetry (elec. parameters), SEM (morphol. images), goniometer (hydrophobisity of the surface), profilometer ( thickness of the polymer coating). Polymer stability was examd. by placing the coated stent into 1:1 soln. of fetal calf serum:seline soln. up to 1 yr and under the mouse skin for 1 wk. Paclitaxel loading were carried out by immersion into drug soln. and its release was detected by HPLC. Reproducible one step method for coating different pyrrole derivs. on stainless steel coronary stents provided thin (single micrometers), uniform coating with various morphol. and hydrophobisity. These surface properties allow to load appropriate amt. of Paclitaxel and to release it slowly up to a month. [on SciFinder(R)]

The assembly of poly(lactic acid) (PLA) nanoparticles on a 12-aminodecanoic acid (ADA) self-assembled monolayer (SAM) is described. Assembly is accomplished through electrostatic interactions between the positively charged SAM and the negatively charged PLA nanoparticles. The strategy used involves two steps in which a preliminary electrochemical coating of the ADA SAM is followed by a second step that involves immersing the SAM in a solution containing gold or PLA nanoparticles. The SAM was characterized by using cyclic voltammetry (CV), X-ray photoelectron spectroscopy (XPS), FTIR spectroscopy, and contact angle measurements, whereas scanning electron microscopy (SEM) was used to image the nanoparticles after electrostatic attachment was achieved. We found that the surface coverage of the nanoparticles could be controlled by modulating the electrostatic interactions between the negatively charged particles and the positively charged SAM surface by varying the pH of the nanoparticle solution, the immersion time, and the number of cyclic voltammetry scans under which the SAM was formed.[on SciFinder (R)]

The assembly of poly(lactic acid) (PLA) nanoparticles on a 12-aminodecanoic acid (ADA) self-assembled monolayer (SAM) is described. Assembly is accomplished through electrostatic interactions between the pos. charged SAM and the neg. charged PLA nanoparticles. The strategy used involves 2 steps in which a preliminary electrochem. coating of the ADA SAM is followed by a second step that involves immersing the SAM in a soln. contg. gold or PLA nanoparticles. The SAM was characterized by cyclic voltammetry (CV), XPS, FTIR spectroscopy, and contact angle measurements, whereas SEM was used to image the nanoparticles after electrostatic attachment was achieved. The authors found that the surface coverage of the nanoparticles could be controlled by modulating the electrostatic interactions between the neg. charged particles and the pos. charged SAM surface by varying the pH of the nanoparticle soln., the immersion time, and the no. of cyclic voltammetry scans under which the SAM was formed. [on SciFinder(R)]

The covalent attachment of a sol-gel thin film onto a glassy carbon electrode was accomplished through the electrochem. redn. of 4-hydroxyphenyldiazonium. The latter forms a very thin layer on the glassy carbon with hydroxyl groups, through which the sol-gel is attached. This mol. glue improves the adhesion of thin layers of sol-gel to a carbonaceous surface. [on SciFinder(R)]

Nanoparticles having reactive pyrrole residues were prepd. from poly(1-ethoxyethyl glycidyl ether)-block-poly(L,L-lactide) block copolymer. The nanoparticles were electropolymd. in aq. media through the oxidn. of the pyrrole residue and in the presence of pyrrole to form a nanocomposite thin film. The novel synthesis of these pyrrole-functionalized nanoparticles is described and the electrochem. deposition of the corresponding coating is characterized using electrochem., SEM and EDX. [on SciFinder(R)]

The formation and characterization of nanometer thick sol-gel films are reported. The films were prepd. by spin-coating of a dild. soln. of a silane precursor on a no. of different substrates. The effect of diln., rotation speed and nature of substrate on the thickness and homogeneity of the films was examd. Characterization of the films was carried out by profilometry, reflectance spectroscopy, at. force microscopy, adhesion test and electrochem. We find that the diln. factor has a pronounced effect on the film thickness. Moreover, the time of diln., namely, whether diln. was carried out before or after a period of hydrolysis, has a noticeable effect on the thickness as well as on the permeability of embedded species. [on SciFinder(R)]