Transition Metal

October 9, 2012

Site-Selective Chemistry and the Attachment of Peptides to the Surface of a Microelectrode Array

Melissae Stuart Fellet, Jennifer L. Bartels, Bo Bi, and Kevin D. Moeller

J. Am. Chem. Soc., 2012, 134 (40), pp 16891–16898

Peptides have been site-selectively placed on microelectrode arrays with the use of both thiol-based conjugate additions and Cu(I)-coupling reactions between thiols and aryl halides. The conjugate addition reactions used both acrylate and maleimide Michael acceptors. Of the two methods, the Cu(I)-coupling reactions proved far superior because of their irreversibility. Surfaces constructed with the conjugate addition chemistry were not stable at neutral pHs, especially the surface using the maleimide acceptor. Once a peptide was placed onto the array, it could be monitored in “real-time” for its interactions with a biological receptor.

 

January 20, 2011

Site-Selectively Functionalizing Microelectrode Arrays: The Use of Cu(I)-Catalysts

Jennifer Bartels, Peng Lu, Karl Maurer, Amy V. Walker, and Kevin D. Moeller

Langmuir, 2011, 27 (17), pp 11199–11205

Site-selective Cu(I)-catalyzed reactions have been developed on microelectrode arrays. The reactions are confined to preselected electrodes on the arrays using oxygen as the confining agent. Conditions initially developed for the Cu(I)-catalyzed click reaction have proven general for the coupling of amine, alcohol, and sulfur nucleophiles to both vinyl and aryl iodides. Differences between reactions run on 1-K arrays and reactions run on 12-K arrays can be attributed to the 1-K array reactions being divided cell electrolyses and the 12-K array reactions being undivided cell electrolyses. Reactions on the 12-K arrays benefit from the use of a non-sugar-derived porous reaction layer for the attachment of substrates to the surface of the electrodes. The reactions are sensitive to the nature of the ligand used for the Cu catalyst.

 

November 23, 2010

Building Addressable Libraries: Site-Selective Use of Pd(0) Catalysts on Microelectrode Arrays

Libo Hu, Melissae Stuart, Jun Tian, Karl Maurer, and Kevin D. Moeller

J. Am. Chem. Soc., 2010, 132 (46), pp 16610–16616

Site-selective Pd(0)-catalyzed reactions have been developed to functionalize a microelectrode array. Heck, Suzuki, and allylation reactions have all been accomplished. The reactions are compatible with both 1K and 12K arrays and work best when a nonsugar porous reaction layer is used. Suzuki reactions are faster than the Heck reactions and thus require more careful control of the reactions in order to maintain confinement. The allylation reaction requires a different confining agent than the Heck and Suzuki reactions but can be accomplished nicely with quinone as an oxidant for Pd(0).
 
October 29, 2009

A New Porous Reaction Layer for Developing Addressable Molecular Libraries

Libo Hu, Jennifer L. Bartels, Jeremy W. Bartels, Karl Maurer and Kevin D. Moeller

J. Am. Chem. Soc., 2009, 131(46), 16638–16639

A new diblock copolymer-derived porous reaction layer for microelectrode arrays has been tested for its stability and its compatibility with both site-selective synthesis and electrochemical signaling experiments. The diblock copolymer consisted of a cinnamoyl-substituted polymethacrylate block for attachment to the surface of the array and a bromo-substituted polystyrene block for selective functionalization of the surface proximal to microelectrodes in the array. Site-selective Suzuki, Heck, and Cu(I)-coupling reactions were all performed on the new reaction layer along with electrochemical impedance studies.

 

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