Mark Meyerhoff - Academia.edu (original) (raw)

Papers by Mark Meyerhoff

Journal of Materials Chemistry B, 2018

ACS Applied Bio Materials, 2019

ACS Applied Materials & Interfaces, 2018

Composites Part B: Engineering, 2017

ACS biomaterials science & engineering, Jan 13, 2017

Nitric oxide (NO) has many important physiological functions, including its ability to inhibit pl... more Nitric oxide (NO) has many important physiological functions, including its ability to inhibit platelet activation and serve as potent antimicrobial agent. The multiple roles of NO in vivo have led to great interest in the development of biomaterials that can deliver NO for specific biomedical applications. Herein, we report a simple solvent impregnation technique to incorporate a nontoxic NO donor, S-nitroso-N-acetylpenicillamine (SNAP), into a more biocompatible biomedical grade polymer, CarboSil 20 80A. The resulting polymer-crystal composite material yields a very stable, long-term NO release biomaterial. The SNAP impregnation process is carefully characterized and optimized, and it is shown that SNAP crystal formation occurs in the bulk of the polymer after solvent evaporation. LC-MS results demonstrate that more than 70% of NO release from this new composite material originates from the SNAP embedded CarboSil phase, and not from the SNAP species leaching out into the soaking s...

ACS biomaterials science & engineering, Jan 12, 2016

Nitric oxide (NO) releasing polymers are promising in improving the biocompatibility of medical d... more Nitric oxide (NO) releasing polymers are promising in improving the biocompatibility of medical devices. Polyurethanes are commonly used to prepare/fabricate many devices (e.g., catheters); however, the transport properties of NO within different polyurethanes are less studied, creating a gap in the rational design of new NO releasing devices involving polyurethane materials. Herein, we study the diffusion and partitioning of NO in different biomedical polyurethanes via the time-lag method. The diffusion of NO is positively correlated with the PDMS content within the polyurethanes, which can be rationalized by effective media theory considering various microphase morphologies. Using catheters as a model device, the effect of these transport properties on the NO release profiles and the distribution around an asymmetric dual lumen catheter are simulated using finite element analysis and validated experimentally. This method can be readily applied in studying other NO release medical ...

Acta biomaterialia, Oct 6, 2016

Two major problems with implanted catheters are clotting and infection. Nitric oxide (NO) is an e... more Two major problems with implanted catheters are clotting and infection. Nitric oxide (NO) is an endogenous vasodilator as well as natural inhibitor of platelet adhesion/activation and an antimicrobial agent, and NO-releasing polymers are expected to have similar properties. Here, NO-releasing central venous catheters (CVCs) are fabricated using Elast-eon™ E2As polymer with both diazeniumdiolated dibutylhexanediamine (DBHD/NONO) and poly(lactic-co-glycolic acid) (PLGA) additives, where the NO release can be modulated and optimized via the hydrolysis rate of the PLGA. It is observed that using a 10% w/w additive of a PLGA with ester end group provides the most controlled NO release from the CVCs over a 14d period. The optimized DBHD/NONO-based catheters are non-hemolytic (hemolytic index of 0%) and noncytotoxic (grade 0). After 9d of catheter implantation in the jugular veins of rabbits, the NO-releasing CVCs have a significantly reduced thrombus area (7 times smaller) and a 95% reduc...

Analytica Chimica Acta, 2015

A highly sensitive amperometric gas-phase nitric oxide (NO) sensor based on a Pt working electrod... more A highly sensitive amperometric gas-phase nitric oxide (NO) sensor based on a Pt working electrode chemically deposited on a Nafion film is described. The Pt electrode is chemically deposited on a Nafion 117 membrane by impregnating the film with Pt(NH 3 ) 4 2+ ions, which are then exposed to NaBH 4 to precipitate conductive Pt metal. The sensor was characterized with a mass-flow controlled 1 ppm NO standard gas and has an electrochemical surface area of 34 ± 9 cm 2 , low limits of detection (4.3 ± 1.1 ppb) and a fast response time (<5s) toward changes in gas phase NO levels. Good correlation was found for measurements with the new amperometric Pt-Nafion sensor vs. chemiluminescence results for detecting the rates of NO released from CarboSil 2080A polymer films doped with S-nitroso-N-acetylpenicillamine (R = 0.999, m = 0.999, n = 6) and for electrochemical reduction of nitrite to NO (R = 0.999, m = 0.938, n = 3) mediated by a copper(II)-tri(2-pyridylmethyl)amine complex.

ACS Biomaterials Science & Engineering, 2015

J. Mater. Chem. B, 2014

In a polymer comparison, E2As was found to have superior hemocompatibility and then was used to p... more In a polymer comparison, E2As was found to have superior hemocompatibility and then was used to prepare nitric oxide (NOrel) surfaces and tested in a 4 h rabbit model.

Bioelectrochemistry, 2015

Journal of Materials Chemistry B, 2015

Nitric oxide-releasing catheters, prepared with S-nitroso-N-acetylpenicillamine doped polymers, r... more Nitric oxide-releasing catheters, prepared with S-nitroso-N-acetylpenicillamine doped polymers, reduce thrombus and bacterial adhesion in a 7 day sheep model.

Journal of Biomedical Materials Research Part A, 2013

Journal of biomedical materials research. Part B, Applied biomaterials, 2009

Polyurethanes are widely used in the manufacturing of biomedical catheters and other blood-contac... more Polyurethanes are widely used in the manufacturing of biomedical catheters and other blood-contacting devices; however, thrombus formation still occurs, which renders these catheters ineffective unless systemic anticlotting agents are used. Nitric oxide (NO) is a well-known inhibitor of platelet activity. In the current study, two commercially available medical polyurethanes (Pellethane and Tecophilic) were derivatized to possess NO-generating Cu(II)-cyclen moieties pendant to the polymer backbone. A new three-step synthetic approach is used, that is simpler than a recently reported method to prepare Cu(II)-cyclen-polyurethane materials. Both derivatized polyurethanes were found to produce NO at levels at or above those of endothelial cells. A comparison between the modified commercial polyurethanes (hydrophobic vs. hydrophilic) is presented, including the synthetic scheme, extensive characterization, and coating application. These derivatized polymers may serve as useful coatings t...

Analytical and Bioanalytical Chemistry, 2011

Langmuir : the ACS journal of surfaces and colloids, Jan 16, 2008

A universal nitric oxide (NO) generating surface is assembled via Layer-by-Layer (LbL) deposition... more A universal nitric oxide (NO) generating surface is assembled via Layer-by-Layer (LbL) deposition of sodium alginate (Alg) and organoselenium modified polyethyleneimine (SePEI) on quartz and polymeric substrates. The immobilized SePEI species is capable of catalytically decomposing S-nitrosothiol species (RSNO) to NO in the presence of thiol reducing agents (e.g., glutathione, cysteine, etc.). The stepwise buildup of the multilayer films is monitored by UV-vis spectroscopy, SEM and surface contact angle measurements. X-ray photoelectron spectroscopy is used to study the stoichiometry between the polyanion and polycation, and also the presence of Se in the catalytic LbL film. A reductive annealing process is necessary to improve the stability of freshly coated multilayer films via chain rearrangement. Chemiluminescence measurements illustrate the ability of the LbL films to generate NO from S-nitrosoglutathione (GSNO) in the presence of glutathione (GSH). Enhanced NO fluxes can be ac...

Journal of Pediatric Surgery