Micropatterning of Au NPs on PEG Hydrogels Using Different Silanes To Control Cell Adhesion on the Nanocomposites.

Amino-silanization of silica-based substrates has proven to be effective in guiding the immobilization of citrate-stabilized Au NPs in a good, homogeneous fashion. This accomplishment has formed the basis of fabricating micropatterns of Au NPs on such substrates by patterning of oxidized silicon wafers with (3-aminopropyl)trimethoxysilane (amino-silane) using the microcontact printing (μCP) process. This micropattern of amino-silane is used to specifically adsorb Au NPs. To avoid unspecific adsorption to the nonsilanized areas on the silicon wafers, the nonstamped areas were backfilled with self-assembled monolayers of organosilanes, for example, with methyl- or perfluoro-end-groups. Finally, after having fabricated a micropattern of Au NPs on silicon wafers, the Au NP patterns were transferred onto poly(ethylene glycol) hydrogels by our newly developed procedures, and on these nanocomposite materials, controlled cell adhesion has been achieved. Furthermore, these materials are great candidates for plasmon-based biosensor applications and also for various medical applications, such as for drug delivery systems or photothermal therapies.