Agarose-assisted dip-pen nanolithography of oligonucleotides and proteins.

This paper describes a method for the direct transfer of biomolecules encapsulated within a viscous fluid matrix by dip-pen nanolithography (DPN). The method relies on the use of agarose as a "universal" carrier that is compatible with many types of biomolecules including proteins and oligonucleotides. Agarose-assisted DPN allows one to generate nanoarrays of such materials on activated glass substrates with the same deposition rates for different biomolecules, which will greatly expand future capabilities for parallel, multiplexed biomolecule deposition. The fluidity of the matrix may be systematically varied to control the deposition process, resulting in an additional parameter affecting deposition rates besides tip-substrate contact-time and humidity. Agarose-assisted DPN results in extremely fast biomolecule patterning with typical contact times less than 1 s. Feature sizes as small as 50 nm are demonstrated. The biorecognition properties of both protein and oligonucleotide structures are characterized by studying their reactivity with fluorophore-labeled antibody and complementary oligonucleotide sequences, respectively.