A photochemical method for patterning the immobilization of ligands and cells to self-assembled monolayers.
This work describes a chemically well defined method for patterning ligands to self-assembled monolayers (SAMs) of alkanethiolates on gold. This method begins with monolayers presenting a nitroveratryloxycarbonyl (NVOC)-protected hydroquinone which is photochemically irradiated to reveal a hydroquinone group. The resulting hydroquinone is then oxidized to the corresponding benzoquinone, providing a site for the Diels-Alder mediated immobilization of ligands. The rate constant for the photochemical deprotection is 0.032 s(-1) (with an intensity of approximately 100 mW/cm(2) between 355 and 375 nm), corresponding to a half-life of 21 s. The hydroquinone is oxidized to the benzoquinone using either electrochemical or chemical oxidation and then functionalized by reaction with a cyclopentadiene-tagged ligand. Two methods for patterning the immobilization of ligands are described. In the first, the substrate is illuminated through a mask to generate a pattern of hydroquinone groups, which are elaborated with ligands. In the second method, an optical microscope fit with a programmable translational stage is used to write patterns of deprotection which are then again elaborated with ligands. This technique is characterized by the use of well-defined chemical reactions to control the regions and densities of ligand immobilization and will be important for a range of applications that require patterned ligands for biospecific interactions.
Department of Chemistry, University of Chicago, 5735 S. Ellis Avenue, Chicago, Illinois 60637, USA.
W Shannon
WS
Dillmore
Muhammad N
MN
Yousaf
Milan
M
Mrksich
D016475:3T3 Cells; D000818:Animals; D016227:Benzoquinones / Q000138:chemical synthesis / Q000737:chemistry / Q000528:radiation effects; D002478:Cells, Cultured; D003517:Cyclopentanes / Q000737:chemistry; D004563:Electrochemistry; D019793:Fluorescein / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D006873:Hydroquinones / Q000737:chemistry* / Q000528:radiation effects; D007103:Immobilization; D008024:Ligands; D008567:Membranes, Artificial; D051379:Mice; D015394:Molecular Structure; D009842:Oligopeptides / Q000138:chemical synthesis / Q000737:chemistry / Q000528:radiation effects; D010084:Oxidation-Reduction; D010777:Photochemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D013438:Sulfhydryl Compounds / Q000138:chemical synthesis / Q000737:chemistry* / Q000528:radiation effects; D013499:Surface Properties; D014466:Ultraviolet Rays
D016227:Benzoquinones; D003517:Cyclopentanes; D006873:Hydroquinones; D008024:Ligands; D008567:Membranes, Artificial; D009842:Oligopeptides; D013438:Sulfhydryl Compounds; D011092:Polyethylene Glycols; D006046:Gold; C047981:arginyl-glycyl-aspartic acid; D019793:Fluorescein