Laser assisted deposition of nanopatterned biomolecular layers

This work reports on the production of ultrathin films of biologically functional macromolecules with patterns in the nano to micrometer range and nanometric resolution. This technology is of importance in the quickly developing fields of bioelectronics and molecular electronics. The technique used to immobilize biological molecules in thin uniform films is based on pulsed laser vaporization/ionization of a frozen aqueous solution in a high vacuum vessel. Ionized molecules are then driven to the substrate surface by applied electric fields. Patterning is obtained by electron beam lithography and lift-off. AFM characterization of the films reveals highly uniform near monolayers with nanometric features. The samples are invariably biologically active; comparison with enzymatic reaction kinetics of known concentration solutions gives us a percentage of active molecules in the range of 10-30%. This is sufficient for the production of highly integrated bioelectronic devices. (C) 2003 Elsevier Science B.V. All rights reserved.