SUBPICOSECOND-PULSE LASER MICROSTRUCTURING FOR ENHANCED REPRODUCIBILITY OF BIOSENSORS

Curved substrates can be micro-structured by laser ablation, which is not possible with standard lithographic methods. The novel femtosecond -pulse laser technique allows the :production of defined and reproduci ble micro-perforations of originally analyte-impermeable membranes. Th e trans-membrane analyte flux can be controlled both by the variation of the laser focus diameter resulting in different areas of single per forations, and the number of perforations in arrays on small membrane areas. This leads to a higher degree of variability as well as reprodu cibility of the diffusion qualities of sensor membranes, and marks the main innovation with this technique compared to the hand-made mechani cal perforation by specially grinded needles used up to now. Touchless micro-perforation of small membrane areas with negligible heat damage of the structures adjacent to the perforation allows the application of 'analyte door' membranes directly onto curved surfaces of miniaturi zed needle-sensors assigned for in vivo glucose monitoring, for the fi rst time. (C) 1997 Elsevier Science S.A.