title: Printed protein microarrays on unmodified plastic substrates.
abstract: A key challenge for the generation of protein microarrays is the immobilization of functional capture probe proteins at the chip surfaces. Here, a new concept for a single step production of protein microarrays to unmodified plastic substrates is presented. It is based on the printing of polymer/protein mixtures and the photochemical attachment of the obtained microstructures to the plastic chip surfaces. In the photochemical process three reactions occur simultaneously: transformation of the polymer into hydrogel dots, covalent binding of the forming gel to the substrate, and covalent immobilization of the proteins to the three-dimensional hydrogel scaffold. As an example we use anti-bovine serum albumin as a protein (anti-BSA) and a water swellable polymer network based on polydimethylacrylamide as a scaffold, which is photochemically crosslinked using benzophenone as a crosslinking agent. In one series of microarray experiments the probe density of the immobilized proteins was determined by incorporating fluorescence-labeled anti-BSA in the hydrogels. In a typical experiment, the number of immobilized probes was determined to 4 x 10(9) protein molecules per spot. In other experiments, the microarrays were brought into contact with fluorescently labeled BSA. In such analyses signal-to-noise values of more than 200 were obtained and about 9 x 10(7) antigen molecules were bound per spot. This demonstrates that in a very simple way microarrays with large amount of probes per spot can be realized and that antibodies immobilized in the printed hydrogels remain accessible and retain their functionality.
authors.affiliation: Laboratory for Chemistry and Physics of Interfaces, Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg, Germany.
authors.forename: Meike
authors.initials: M
authors.lastname: Moschallski
authors.forename: Johannes
authors.initials: J
authors.lastname: Baader
authors.forename: Oswald
authors.initials: O
authors.lastname: Prucker
authors.forename: Jürgen
authors.initials: J
authors.lastname: Rühe
mesh_terms: D000178:Acrylamides / Q000737:chemistry; D000906:Antibodies / Q000737:chemistry; D001577:Benzophenones / Q000737:chemistry; D015374:Biosensing Techniques / Q000379:methods; D020100:Hydrogels / Q000737:chemistry; D008856:Microscopy, Fluorescence; D055668:Photochemical Processes; D011108:Polymers / Q000737:chemistry; D040081:Protein Array Analysis / Q000379:methods; D012710:Serum Albumin, Bovine / Q000737:chemistry / Q000276:immunology
chemical_list: D000178:Acrylamides; D000906:Antibodies; D001577:Benzophenones; D020100:Hydrogels; D011108:Polymers; C429790:poly(N,N-dimethylacrylamide); D012710:Serum Albumin, Bovine; C047723:benzophenone