Mass sensitive mechanical resonator based biosensors are a promising label free biological sensing platform due to the capability for high sensitivity, fast response, accurate and real time measurement, integrity with traditional electronics and flexible readout techniques. With the advancement of top down nano fabrication techniques, the dimensions of mechanical resonators scale from the micrometer down to the nanometer range. Recently, we have realized sub-10 nm glassy SiCN nanowire resonators by employing electron beam lithography. The SiCN nanomechanical resonator biosensors are advantageous in terms of large array integration, lowering the detection limit and potential for multiple targets detection. However, the currently used surface modification techniques for SiCN material are either chemical unstable or biological incompatible, which causes instability and unreliability of the bio sensing system. Our research aims at implementing robust and biocompatible surface modification chemistry, diazonium salt reduction induced aryl film grafting process, for the biofunctionalization of SiCN nanomechanical biosensors. We used X-ray photoelectron spectroscopy (XPS) to analyze the chemically modified SiCN surfaces and verified the strong interfacial chemical bonding between the aryl film and SiCN surfaces. The diaznonium modified nanoresonators’ surface was covalently immobilized with anti-rabbit IgG as a recognition agent, for the purpose of specific detection, and the induced resonant frequencies down shifts were detected by laser interferometry. The immobilization of target protein rabbit IgG onto these devices was successfully observed by significant further downshifts of resonant frequencies. The specificity of this sensor detection was confirmed by comparison to negative control. Surface inspection of functionalized nanowire resonators by Helium Ion Microscopy further verifies the successful functionalization of nanostring resonators.

Diazonium functionalization of nanowire mechanical resonator biosensors for improved stability

250th National Meeting (2015)

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