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Research Article

Submicron Streptavidin Patterns for Protein Assembly

Karen L. Christman,^†^‡ Michael V. Requa,^§ Vanessa D. Enriquez-Rios,^† Sabrina C. Ward, Kenneth A. Bradley,^‡ Kimberly L. Turner,^§^‡ and Heather D. Maynard*^†^‡

Department of Chemistry and Biochemistry, Department of Microbiology, Immunology, and Molecular Genetics, California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California, 90095, and Department of Mechanical Engineering, California NanoSystems Institute, University of California, Santa Barbara, Santa Barbara, California 93106

Langmuir, 2006, 22 (17), pp 7444–7450

DOI: 10.1021/la0608213

Publication Date (Web): July 19, 2006

†

Department of Chemistry and Biochemistry, University of California, Los Angeles.

‡

California NanoSystems Institute, University of California, Los Angeles, Santa Barbara.

Department of Mechanical Engineering, University of California, Santa Barbara.

Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles.

Corresponding author. E-mail: maynard@chem.ucla.edu. Phone: (310) 267-5162. Address: Department of Chemistry and Biochemistry, 607 Charles E. Young Drive East, University of California, Los Angeles, CA 90095-1569.

Abstract

Micron and submicron-scale features of aldehyde functionality were fabricated in polymer films by photolithography to develop a platform for protein immobilization and assembly at a biologically relevant scale. Films containing the pH-reactive polymer poly(3,3‘-diethoxypropyl methacrylate) and a photoacid generator (PAG) were patterned from 500 nm to 40 μm by exposure to 365 nm (i-line) light. Upon PAG activation and hydrolysis of acetals, aldehyde groups formed. After the films were incubated with a biotinylated aldehyde reactive probe, the X-ray photoelectron spectroscopy results were consistent with biotin being attached to the surface. The background was subsequently passivated by flood exposure and incubation with an aminooxy-terminated poly(ethylene glycol), resulting in a 98% reduction in nonspecific protein adsorption. Protein patterning and assembly was demonstrated using streptavidin, biotinylated anthrax toxin receptor-1, and the protective antigen moiety of anthrax toxin and confirmed by fluorescence microscopy and atomic force microscopy (AFM). AFM demonstrated that 500 nm protein features were achieved. Because of the abundance of biotinylated proteins, this methodology provides a platform for protein immobilization and assembly for various applications in biotechnology.

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