Novel full platinum nanoprobes suitable for biological SPM experiments

Abstract

We have developed a hybrid scanning probe microscopy sensor consisting of a SU-8 body and full platinum cantilever and tip. The fabrication process is based on surface-micromachining of a silicon wafer, where oxidation sharpened moulds define the tip shape, giving tips with a radius sharper than 20 nm. With optimized sputter deposition parameters we obtained fully straight platinum cantilevers after release. The release is based on a dry isotropic silicon under-etching. Platinum shows biocompatibility, making the sensors suitable for imaging and force spectroscopy of living cells. A resonance frequency of 252 KHz and a mechanical quality factor of 56 are measured in air for a cantilever of 35 mumtimes20 mumtimes0.5 mum. A method for the immobilization of cells in cell-containers is developed to simplify their localization and imaging