Micromachining of a newly designed AFM probe integrated with hollow microneedle for cellular function analysis

Abstract

In order to realize cellular function analysis in a single living cell, we have been developing a newly designed probe for atomic force microscope (AFM), named bioprobe. The proposed bioprobe has a conventional sharp tip superseded by a hollow silicon dioxide microneedle connecting the root to a fluidic microchannel embedded into a silicon (Si) cantilever beam structure. The probe will be capable not only of performing AFM measurements but also of introducing desired biomolecules (DNA, proteins, etc.) into living cells and extracting biomolecules expressed in the cells. In this paper, we describe the most important techniques for fabricating microneedles with a sharpened tip. Then, in order to give mechanical strength enough to be used as AFM probes, a simple fabrication process for structuring Si microstructure close to the base of a needle was proposed. By employing the developed techniques, the prototype bioprobes were successfully fabricated. It was also demonstrated the fabricated probe proved capable of taking AFM images.