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George M. Whitesides

Bio: George M. Whitesides is an academic researcher from Harvard University. The author has contributed to research in topics: Microcontact printing & Self-assembled monolayer. The author has an hindex of 240, co-authored 1739 publications receiving 269833 citations. Previous affiliations of George M. Whitesides include University of California, Davis & University of Texas at Austin.


Papers
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Journal ArticleDOI
TL;DR: Gao et al. as discussed by the authors used Indium-Mediated Allylation of 2,3:4,5-Di-O-isopropylidene-D-arabinose in Aqueous Media.
Abstract: The Journal of Organic Chemistry is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Synthesis of KDO Using Indium-Mediated Allylation of 2,3:4,5-Di-O-isopropylidene-D-arabinose in Aqueous Media Jinming Gao, Ralph Haerter, Dana M. Gordon, and George M. Whitesides J. Org. Chem., 1994, 59 (13), 3714-3715• DOI: 10.1021/jo00092a040 • Publication Date (Web): 01 May 2002 Downloaded from http://pubs.acs.org on May 13, 2009

82 citations

Journal ArticleDOI
TL;DR: The balance of enthalpic and entropic contributions to the hydrophobic effect in this representative system of protein and ligand seem to comprise approximately equal contributions from enthalpy and entropy (from release of water from configurationally restricted positions).
Abstract: The hydrophobic effect, the free-energetically favorable association of nonpolar solutes in water, makes a dominant contribution to binding of many systems of ligands and proteins. The objective of this study was to examine the hydrophobic effect in biomolecular recognition using two chemically different but structurally similar hydrophobic groups, aliphatic hydrocarbons and aliphatic fluorocarbons, and to determine whether the hydrophobicity of the two groups could be distinguished by thermodynamic and biostructural analysis. This paper uses isothermal titration calorimetry (ITC) to examine the thermodynamics of binding of benzenesulfonamides substituted in the para position with alkyl and fluoroalkyl chains (H2NSO2C6H4-CONHCH2(CX2)nCX3, n = 0–4, X = H, F) to human carbonic anhydrase II (HCA II). Both alkyl and fluoroalkyl substituents contribute favorably to the enthalpy and the entropy of binding; these contributions increase as the length of chain of the hydrophobic substituent increases. Crystallogra...

82 citations

Journal ArticleDOI
TL;DR: In this article, the authors compared the J(V) characteristics obtained for self-assembled monolayer (SAM)-based tunneling junctions with top electrodes of the liquid eutectic of gallium and indium (EGaIn) fabricated using two different procedures: stabilizing the EGaIn electrode in PDMS microchannels and suspending the EgaIn electrode from the tip of a syringe.
Abstract: This paper compares the J(V) characteristics obtained for self-assembled monolayer (SAM)-based tunneling junctions with top electrodes of the liquid eutectic of gallium and indium (EGaIn) fabricated using two different procedures: (i) stabilizing the EGaIn electrode in PDMS microchannels and (ii) suspending the EGaIn electrode from the tip of a syringe. These two geometries of the EGaIn electrode (with, at least when in contact with air, its solid Ga2O3 surface film) produce indistinguishable data. The junctions incorporated SAMs of SCn–1CH3 (with n = 12, 14, 16, or 18) supported on ultraflat, template-stripped silver electrodes. Both methods generated high yields of junctions (70–85%) that were stable enough to conduct measurements of J(V) with statistically large numbers of data (N = 400–1000). The devices with the top electrode stabilized in microchannels also made it possible to conduct measurements of J(V) as a function of temperature, almost down to liquid nitrogen temperatures (T = 110–293 K). The ...

81 citations

Journal ArticleDOI
01 Mar 2003-Langmuir
TL;DR: In this paper, the authors describe a synthesis of free-standing, 10−15-nm-thick polymer films of well-defined lateral size and shape using microcontact printing.
Abstract: This paper describes a synthesis of free-standing, 10−15-nm-thick polymer films of well-defined lateral size and shape. The three key elements of this procedure are (1) formation by microcontact printing (μCP) of a patterned, self-assembled monolayer (SAM) with hydrophobic regions (alkane-terminated) and adsorption-resistant regions (oligo(ethylene oxide)-terminated); (2) initiation of spatially selective growth of films of poly(electrolyte) multilayers by adsorption on the hydrophobic regions of the patterned SAM; and (3) dry transfer of these films to a water-soluble sacrificial backing, from which the films can be released into solution. This technique exploits the hydrophobic effect as an interaction that can be switched off when it is not needed: during the growth of the films in aqueous buffer, the hydrophobic effect anchors the polymers to the surface; once these films have been dried after synthesis, they are bound to the substrate only by van der Waals interactions and can be transferred nondest...

81 citations

Patent
10 Feb 1997
TL;DR: In this article, a technique for forming high-carbon structural articles, such as glassy carbon articles, is provided that involves molding fluid precursors of the article into a predetermined shape, followed by carbonization of the articles.
Abstract: A technique for forming high-carbon structural articles, such as glassy carbon articles, is provided that involves molding fluid precursors of the article into a predetermined shape, followed by carbonization of the articles An elastomeric mold can be used to mold the precursors, and the resultant, free-standing articles have features on the micron or nanometer scale A variety of useful articles including sensors, actuators, microelectromechanical systems, transmission electron microscopy grids, and the like are provided

81 citations


Cited by
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[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

28 Jul 2005
TL;DR: PfPMP1)与感染红细胞、树突状组胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作�ly.
Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1(PfPMP1)与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员,通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

18,940 citations

Journal ArticleDOI
TL;DR: Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols used xiii 1.
Abstract: Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

14,171 citations

Journal ArticleDOI
05 Feb 2009-Nature
TL;DR: The direct synthesis of large-scale graphene films using chemical vapour deposition on thin nickel layers is reported, and two different methods of patterning the films and transferring them to arbitrary substrates are presented, implying that the quality of graphene grown by chemical vapours is as high as mechanically cleaved graphene.
Abstract: Problems associated with large-scale pattern growth of graphene constitute one of the main obstacles to using this material in device applications. Recently, macroscopic-scale graphene films were prepared by two-dimensional assembly of graphene sheets chemically derived from graphite crystals and graphene oxides. However, the sheet resistance of these films was found to be much larger than theoretically expected values. Here we report the direct synthesis of large-scale graphene films using chemical vapour deposition on thin nickel layers, and present two different methods of patterning the films and transferring them to arbitrary substrates. The transferred graphene films show very low sheet resistance of approximately 280 Omega per square, with approximately 80 per cent optical transparency. At low temperatures, the monolayers transferred to silicon dioxide substrates show electron mobility greater than 3,700 cm(2) V(-1) s(-1) and exhibit the half-integer quantum Hall effect, implying that the quality of graphene grown by chemical vapour deposition is as high as mechanically cleaved graphene. Employing the outstanding mechanical properties of graphene, we also demonstrate the macroscopic use of these highly conducting and transparent electrodes in flexible, stretchable, foldable electronics.

10,033 citations

Journal ArticleDOI
29 Aug 1997-Science
TL;DR: In this article, a general approach for multilayers by consecutive adsorption of polyanions and polycations has been proposed and has been extended to other materials such as proteins or colloids.
Abstract: Multilayer films of organic compounds on solid surfaces have been studied for more than 60 years because they allow fabrication of multicomposite molecular assemblies of tailored architecture. However, both the Langmuir-Blodgett technique and chemisorption from solution can be used only with certain classes of molecules. An alternative approach—fabrication of multilayers by consecutive adsorption of polyanions and polycations—is far more general and has been extended to other materials such as proteins or colloids. Because polymers are typically flexible molecules, the resulting superlattice architectures are somewhat fuzzy structures, but the absence of crystallinity in these films is expected to be beneficial for many potential applications.

9,593 citations