Protein patterning on polycrystalline silicon–germanium via standard UV lithography for bioMEMS applications

• Published in: Materials Science & Engineering C Vol. 30; no. 8; pp. 1221 - 1226
• Main Authors: Lenci, S., Tedeschi, L., Domenici, C., Lande, C., Nannini, A., Pennelli, G., Pieri, F., Severi, S.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 12-10-2010
• Subjects: BioMEMS; Biosensors; CMOS; Devices; Immobilization; Microelectromechanical systems; Polycrystalline silicon–germanium; Protein patterning; Proteins; Scanning electron microscopy; Silanes; Silanization; Surface chemistry; Protein patterning; Silanization; Polycrystalline silicon–germanium; BioMEMS
• ISSN: 0928-4931; 1873-0191
• DOI: 10.1016/j.msec.2010.07.002

Polycrystalline silicon–germanium (poly-SiGe) is a promising structural material for the post-processing of micro electro-mechanical systems (MEMS) on top of complementary metal-oxide-semiconductor (CMOS) substrates. Combining MEMS and CMOS allows for the development of high-performance devices. We present for the first time selective protein immobilization on top of poly-SiGe surfaces, an enabling technique for the development of novel poly-SiGe based MEMS biosensors. Active regions made of 3-aminopropyl-triethoxysilane (APTES) were defined using silane deposition onto photoresist patterns followed by lift-off in organic solvents. Subsequently, proteins were covalently bound on the created APTES patterns. Fluorescein-labeled human serum albumin (HSA) was used to verify the immobilization procedure while the binding capability of the protein layer was tested by an antigen-labeled antibody pair. Inspection by fluorescence microscopy showed protein immobilization inside the desired bioactive areas and low non-specific adsorption outside the APTES pattern. Furthermore, the quality of the silane patches was investigated by treatment with 30
nm-diameter gold nanoparticles and scanning electron microscope observation. The developed technique is therefore a promising first step towards the realization of poly-SiGe based biosensors.