Chemical Lithography with Monomolecular Templates

The motivation behind this work was the development of a new approach to immobilize single stranded DNA within a biorepulsive template in a broad range of compositions and to fabricate ssDNA patterns of arbitrary shape and size imbedded into biorepulsive matrix. This approach relies on so called irradiation promoted exchange reaction within the general concept of Chemical Lithography. The key idea of IPER is tuning the extent of the exchange reaction between the primary self-assembled monolayer covering the substrate and a molecular substituent in solution by electron irradiation, which allows fabrication of binary mixed SAMs of variable compositions depending on the selected dose. The physics behind this method is the creation of chemical and structural defects in the primary SAM, which promote the exchange reaction. Within this work, the IPER approach was extended to a specific task of controlled and site specific immobilization of ssDNA on Au (111) substrate. To suppress the nonspecific adsorption events beyond the seeded ssDNA species, a biorepulsive oligo(ethylene glycol) substituted alkanethiolate monolayer was used as the primary matrix for the exchange reaction.