A protein patterning technique and Its application in bio-inspired self-assembly

Protein patterning techniques are crucial for the development of antibody-based biosensor and the study of controlled cell growth. This paper discusses a protein patterning technique based on microelectronic fabrication, DNA hybridization and biotin-streptavidin pair. A gold-on-silicon-dioxide substrate with micron size pattern was fabricated with photolithography and lift-off process. The average surface roughness of the gold pattern is 4.3 nm, measured by contact mode AFM. Thiol derivatized single stranded DNA was attached to the gold pattern surface by the chemical bonding between gold atom and sulfur atom. Surface attached DNA was then hybridized with a biotin conjugated complementary DNA sequence. Thus, the gold pattern was translated into a biotin pattern with similar resolution. Fluorescein conjugated streptavidin was patterned as demonstration. Fluorescence microscopy shows relative uniform streptavidin coverage of micron resolution and low background non-specific binding. The proposed protein patterning technique takes advantage of the high resolution of modern microelectronic fabrication. It has the potential of reaching sub-micron resolution. The biotin-streptavidin pair provides extremely specific and stable linking for protein immobilization. To show its application in biological inspired self-assembly, this technique was used successfully in the self-assembly of 20 nm streptavidin conjugated gold particles.