The Experts below are selected from a list of 150 Experts worldwide ranked by ideXlab platform
George M Whitesides - One of the best experts on this subject based on the ideXlab platform.
-
a survey of structure property relationships of surfaces that resist the adsorption of protein
Langmuir, 2001Co-Authors: Emanuele Ostuni, Robe G Chapma, Erik R Holmli, And Shuichi Takayama, George M WhitesidesAbstract:This paper describes the use of surface plasmon resonance (SPR) spectroscopy and self-assembled monolayers (SAMs) to determine the characteristics of functional groups that give surfaces the ability to resist the nonspecific adsorption of proteins from solution. Mixed SAMs presenting different functional groups were prepared for screening using a synthetic protocol based on the reaction of organic amines with a SAM terminated by interchain Carboxylic Anhydride groups. Surfaces that presented derivatives of oligo(sarcosine), N-acetylpiperazine, and permethylated sorbitol groups were particularly effective in resisting the adsorption of proteins. Incorporation of these groups into single-component SAMs resulted in surfaces that are comparable to (but slightly less good than) single-component SAMs that present oligo(ethylene glycol) in their ability to resist the adsorption of proteins. In the group of surfaces examined, those that resisted the adsorption of proteins had the following properties: they were ...
-
Preparation of Mixed Self-Assembled Monolayers (SAMs) That Resist Adsorption of Proteins Using the Reaction of Amines with a SAM That Presents Interchain Carboxylic Anhydride Groups
Langmuir, 2000Co-Authors: Robert Chapman, Emanuele Ostuni, And Lin Yan, George M WhitesidesAbstract:This paper describes a procedure for preparing mixed self-assembled monolayers (mixed SAMs) on gold that resist the nonspecific adsorption of proteins from solution. This method was tested using α-amino derivatives of ω-hydroxy- and ω-methoxy-oligo(ethylene glycols): H2N(CH2CH2O)nCH3 and H2N(CH2CH2O)nH (n = 3, 6). Mixed SAMs were prepared by allowing these amines to react with a SAM presenting interchain Carboxylic Anhydride groups. The resistance of the resulting surfaces to adsorption of several proteinscarbonic anhydrase (EC 4.2.1.1), ribonuclease A (EC 3.1.27.5), lysozyme (EC 3.2.1.17), and fibrinogenwas examined using surface plasmon resonance (SPR) spectroscopy. These mixed SAMs resist the nonspecific adsorption of proteins approximately as effectively as single-component SAMs prepared using the conventional method involving chemisorption of oligo(ethylene glycol)-terminated alkanethiols on gold. Characterization of the mixed SAM that presents a 1:1 mixture of −OCNH(CH2CH2O)6CH3 and CO2H/CO2- group...
-
patterning thin films of poly ethylene imine on a reactive sam using microcontact printing
Langmuir, 1999Co-Authors: Wilhelm T S Huck, And Xiaomei Zhao, George M WhitesidesAbstract:This paper describes the patterning of poly(ethylene imine) (PEI) on a surface into structures having submicron edge resolution. This procedure consists of three steps: (1) formation of a reactive self-assembled monolayer (SAM) terminating in interchain Carboxylic Anhydride groups on gold and silver; (2) patterning of this SAM by microcontact printing (μCP) using a poly(dimethylsiloxane) (PDMS) stamp inked with PEI (this polymer contains primary and secondary amines that are reactive toward the Anhydride groups); (3) hydrolysis of the unreacted Anhydride groups with base and removal of noncovalently bound PEI. The patterned thin films of PEI are attached covalently to the SAM by amide bonds. The pendant, unreacted primary and secondary amines of the attached PEI can be used as reactive nucleophilic groups in further steps of chemical modification. This type of postmodification has been illustrated by allowing the amine groups of the covalently attached PEI to react with perfluorooctanoyl chloride, palmit...
-
formation and reaction of interchain Carboxylic Anhydride groups on self assembled monolayers on gold
Langmuir, 1997Co-Authors: Lin Yan, Christian Marzolin, And Andreas Terfort, George M WhitesidesAbstract:This paper demonstrates a new method for the synthesis of mixed self-assembled monolayers (mixed SAMs) by reaction of a reactive intermediatean interchain Carboxylic Anhydridewith alkylamines. The interchain Anhydride was prepared in high yield from a SAM of 16-mercaptohexadecanoic acid (HS(CH2)15COOH) on gold by treatment with trifluoroacetic Anhydride. Alkylamines reacted cleanly with the interchain Anhydride to generate a mixed SAM, which comprised a mixture of acids and amides in approximately 1:1 ratio on the surface. The SAMs of the interchain Anhydride and the mixed SAM were characterized using polarized infrared external reflectance spectroscopy, X-ray photoelectron spectroscopy, contact angle, and ellipsometry. Control of the wettability of the SAMs was demonstrated by allowing the interchain Anhydride to react with alkylamines having different alkyl groups; this model system gave wetting data consistent with earlier studies of mixed monolayers and verified the ability of this method to manipulat...
Teruaki Mukaiyama - One of the best experts on this subject based on the ideXlab platform.
-
kinetic resolution of racemic secondary benzylic alcohols by the enantioselective esterification using pyridine 3 Carboxylic Anhydride 3 pca with chiral acyl transfer catalysts
Helvetica Chimica Acta, 2012Co-Authors: Isamu Shiina, Kenya Nakata, Keisuke Ono, Teruaki MukaiyamaAbstract:Pyridine-3-Carboxylic Anhydride (3-PCA) was found to function as an efficient coupling reagent for the preparation of Carboxylic esters from various Carboxylic acids with alcohols under mild conditions by a simple experimental procedure. This novel condensation reagent 3-PCA was applicable not only for the synthesis of achiral Carboxylic esters catalyzed by 4-(dimethylamino)pyridine (DMAP) but also for the production of chiral Carboxylic esters by the combination of chiral nucleophilic catalyst, such as tetramisole (=2,3,5,6-tetrahydro-6-phenylimidazo[2,1-b][1,3]thiazole) derivatives. An efficient kinetic resolution of racemic benzylic alcohols with achiral Carboxylic acids was achieved by using 3-PCA in the presence of (R)-benzotetramisole ((R)-BTM), and a variety of optically active Carboxylic esters were produced with high enantiomeric excesses by this new chiral induction system without using a tertiary amine.
-
a versatile practical and inexpensive reagent pyridine 3 Carboxylic Anhydride 3 pca for condensation reactions
Bulletin of the Chemical Society of Japan, 2008Co-Authors: Setsuo Funasaka, Teruaki MukaiyamaAbstract:A highly useful method for the preparation of Carboxylic esters and carboxamides from various Carboxylic acids was established by using a novel condensing reagent, pyridine-3-Carboxylic Anhydride (...
-
pyridine 3 Carboxylic Anhydride 3 pca a versatile practical and inexpensive reagent for condensation reaction between Carboxylic acids and alcohols
ChemInform, 2007Co-Authors: Teruaki Mukaiyama, Setsuo FunasakaAbstract:A synthesis of Carboxylic esters from various Carboxylic acids and alcohols is successfully carried out by using a condensation reagent, pyridine-3-Carboxylic Anhydride (3-PCA). This reaction mater...
-
efficient method for dehydration condensation using pyridine 3 Carboxylic Anhydride 3 pca synthesis of carboxamides from nearly equimolar amounts of Carboxylic acids and amines
Chemistry Letters, 2007Co-Authors: Setsuo Funasaka, Teruaki MukaiyamaAbstract:A highly useful method for the preparation of carboxamides from various Carboxylic acids and amines is established by using pyridine-3-Carboxylic Anhydride (3-PCA) in the presence of 4-(dimethylami...
Setsuo Funasaka - One of the best experts on this subject based on the ideXlab platform.
-
a versatile practical and inexpensive reagent pyridine 3 Carboxylic Anhydride 3 pca for condensation reactions
Bulletin of the Chemical Society of Japan, 2008Co-Authors: Setsuo Funasaka, Teruaki MukaiyamaAbstract:A highly useful method for the preparation of Carboxylic esters and carboxamides from various Carboxylic acids was established by using a novel condensing reagent, pyridine-3-Carboxylic Anhydride (...
-
pyridine 3 Carboxylic Anhydride 3 pca a versatile practical and inexpensive reagent for condensation reaction between Carboxylic acids and alcohols
ChemInform, 2007Co-Authors: Teruaki Mukaiyama, Setsuo FunasakaAbstract:A synthesis of Carboxylic esters from various Carboxylic acids and alcohols is successfully carried out by using a condensation reagent, pyridine-3-Carboxylic Anhydride (3-PCA). This reaction mater...
-
efficient method for dehydration condensation using pyridine 3 Carboxylic Anhydride 3 pca synthesis of carboxamides from nearly equimolar amounts of Carboxylic acids and amines
Chemistry Letters, 2007Co-Authors: Setsuo Funasaka, Teruaki MukaiyamaAbstract:A highly useful method for the preparation of carboxamides from various Carboxylic acids and amines is established by using pyridine-3-Carboxylic Anhydride (3-PCA) in the presence of 4-(dimethylami...
Emanuele Ostuni - One of the best experts on this subject based on the ideXlab platform.
-
a survey of structure property relationships of surfaces that resist the adsorption of protein
Langmuir, 2001Co-Authors: Emanuele Ostuni, Robe G Chapma, Erik R Holmli, And Shuichi Takayama, George M WhitesidesAbstract:This paper describes the use of surface plasmon resonance (SPR) spectroscopy and self-assembled monolayers (SAMs) to determine the characteristics of functional groups that give surfaces the ability to resist the nonspecific adsorption of proteins from solution. Mixed SAMs presenting different functional groups were prepared for screening using a synthetic protocol based on the reaction of organic amines with a SAM terminated by interchain Carboxylic Anhydride groups. Surfaces that presented derivatives of oligo(sarcosine), N-acetylpiperazine, and permethylated sorbitol groups were particularly effective in resisting the adsorption of proteins. Incorporation of these groups into single-component SAMs resulted in surfaces that are comparable to (but slightly less good than) single-component SAMs that present oligo(ethylene glycol) in their ability to resist the adsorption of proteins. In the group of surfaces examined, those that resisted the adsorption of proteins had the following properties: they were ...
-
Preparation of Mixed Self-Assembled Monolayers (SAMs) That Resist Adsorption of Proteins Using the Reaction of Amines with a SAM That Presents Interchain Carboxylic Anhydride Groups
Langmuir, 2000Co-Authors: Robert Chapman, Emanuele Ostuni, And Lin Yan, George M WhitesidesAbstract:This paper describes a procedure for preparing mixed self-assembled monolayers (mixed SAMs) on gold that resist the nonspecific adsorption of proteins from solution. This method was tested using α-amino derivatives of ω-hydroxy- and ω-methoxy-oligo(ethylene glycols): H2N(CH2CH2O)nCH3 and H2N(CH2CH2O)nH (n = 3, 6). Mixed SAMs were prepared by allowing these amines to react with a SAM presenting interchain Carboxylic Anhydride groups. The resistance of the resulting surfaces to adsorption of several proteinscarbonic anhydrase (EC 4.2.1.1), ribonuclease A (EC 3.1.27.5), lysozyme (EC 3.2.1.17), and fibrinogenwas examined using surface plasmon resonance (SPR) spectroscopy. These mixed SAMs resist the nonspecific adsorption of proteins approximately as effectively as single-component SAMs prepared using the conventional method involving chemisorption of oligo(ethylene glycol)-terminated alkanethiols on gold. Characterization of the mixed SAM that presents a 1:1 mixture of −OCNH(CH2CH2O)6CH3 and CO2H/CO2- group...
Didier Bourissou - One of the best experts on this subject based on the ideXlab platform.
-
lipase catalyzed ring opening polymerization of the o Carboxylic Anhydride derived from lactic acid
Biomacromolecules, 2009Co-Authors: Colin Bonduelle, Blanca Martinvaca, Didier BourissouAbstract:Both lipase PS and Novozym 435 promote the ring-opening polymerization of lacOCA, the O-Carboxylic Anhydride derived from lactic acid. Accordingly, PLA of relatively high molecular weights (Mn up to 38400 g/mol) and low polydispersities (Mw/Mn < 1.4) are obtained in high yields within a few hours at 80 °C. Slight preference for l-lacOCA over d-lacOCA is observed, and with Novozym 435, the molecular weight of the obtained PLA can be controlled by varying the lipase loading.
-
Monomer versus alcohol activation in the 4-dimethylaminopyridine-catalyzed ring-opening polymerization of lactide and lactic O-Carboxylic Anhydride.
Chemistry (Weinheim an der Bergstrasse Germany), 2008Co-Authors: Colin Bonduelle, Blanca Martin-vaca, Fernando P. Cossío, Didier BourissouAbstract:Model reactions for the 4-dimethylaminopyridine (DMAP)-catalyzed ring-opening polymerization of lactide and the corresponding lactic O-Carboxylic Anhydride (lacOCA) have been studied computationally at the B3LYP/6-31G(d) level of theory. The solvent effect of dichloromethane was taken into account through PCM/SCRF single-point calculations at the B3LYP/6-31G(d) level of theory. In marked contrast with that predicted for the reaction of alcohols with acetic Anhydride, the mechanism in which nucleophilic activation of the monomer involving acylpyridinium intermediates was found to be energetically less favorable than the base activation of the alcohol through hydrogen bonding. The concerted pathway for the ring-opening of lactide and lacOCA was shown to compete with the traditional stepwise mechanism involving tetrahedral intermediates. Furthermore, DMAP is proposed to act as a bifunctional catalyst through its basic nitrogen center and an acidic ortho-hydrogen atom.