Soft lithography, e.g., microcontact printing (μCP), has been used to generate chemical patterns on noble metal surfaces for biological applications including biosensing and protein-ligand interaction assays, and for studying cellular behavior on solid substrates. However, soft lithography suffers from lateral ink diffusion and gas-phase deposition of volatile inks during printing that can result in poor quality patterns. To overcome such limitations, we have devised a number of modified soft lithography methods, e.g., microdisplacement printing, microcontact insertion printing. Recently, we discovered chemical lift‑off lithography (CLL), which utilizes contact-induced reactions between activated stamps and hydroxyl-terminated alkanethiol SAMs on gold surfaces to lift-off alkanethiols. Lift-off occurs only in the contact areas where surface chemistries of the stamp and the SAM are complementary avoiding commonly encountered problems in μCP. Using CLL, patterns of surface-tethered neurotransmitters are fabricated with high pattern fidelity for the placement of bioactive molecules via backfilling. We found that patterning tether molecules pre-functionalized with neurotransmitters showed consistent antibody recognition and improved specific binding compared to previous post-patterning functionalization approaches. CLL does not remove all alkanethiols in the contact regions and the remaining alkanethiols act as spacers for controlling the density of the active backfilled molecules. We found that the SAM conformation of remaining alkanethiols modulates access to the gold substrate surfaces. Together, these advantages enable highly controlled biomolecule patterns to be created.

Biomolecular patterning via chemical lift-off lithography

249th National Meeting (2015)

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