Bottom-up assembly of silicon nanowire conductometric sensors for the detection of apolipoprotein A1, a biomarker for bladder cancer
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The authors describe highly sensitivity nanowire sensors that can be prepared by a bottom-up approach. The sensors were incorporated into microchannels and used for the quantitative conductometric detection of apolipoprotein A1 (APOA1), a bladder cancer protein biomarker. Silicon nanowires were placed in the gap between nickel electrodes by using dielectrophoretic forces, which improved the yield of the assembly. Then, the nanowires were clipped by another nickel layer to form a nickel/nanowire/nickel sandwich-like structure using photolithography and a lift-off process. The results show that this structure exhibits reduced contact resistance at the interface between the nickel layer and the silicon nanowires, which is an ohmic contact. Thus, a stable nanowire sensor was obtained. It was found that the contact resistance can be further decreased by using a hot plate annealing process. An SU-8 photoresist was used to insulate the electrodes to allow for applications in wet environments. An antibody against APOA1 was covalently conjugated to the surface of the silicon nanowires. Antibody conjugation was verified via the decrease in the conductance of the nanowires after conjugation. The sensor has a dynamic range that covers the 0.2 ng·mL−1 to 10 μg·mL−1 APOA1 concentration range and a detection limit of approximately 1 ng·mL−1.
KeywordsDielectrophoresis Label-free detection Protein detection Microfluidics Nanoscale sensor Sandwich structure
The authors thank Prof. Yit-Tsong Chen from National Taiwan University for providing the silicon nanowire and offering valuable suggestions. We also express our gratitude to the Ministry of Science and Technology of Taiwan and the Chang Gung Memorial Hospital for their funding support (MOST 103-2221-E-182-016-MY2, CMRPD2C0091, BMRPC01).
Compliance with ethical standards
The author(s) declare that they have no competing interests.
- 1.Chen YT, Chen HW, Domanski D, Smith DS, Liang KH, Wu CC, Chen CL, Chung T, Chen MC, Chang YS, Parker CE, Borchers CH, Yu JS (2012) Multiplexed quantification of 63 proteins in human urine by multiple reaction monitoring-based mass spectrometry for discovery of potential bladder cancer biomarkers. J Proteome 75:3529–3545. doi: 10.1016/j.jprot.2011.12.031 CrossRefGoogle Scholar
- 34.Kim KW, Song J, Liu Q, Kee JS, Shin Y, Park MK (2012) Development of multiplexed silicon dual microring sensor for the detection of bladder cancer markers. In: Photonics global conference (PGC). IEEE, Piscataway, pp 1–4. doi: 10.1109/PGC.2012.6458029