Patterning a nanowell sensor biochip for specific and rapid detection of bacteria

✍ Scribed by Sungkyu Seo; Maria Dobozi-King; Ryland F. Young; Laszlo B. Kish; Mosong Cheng

• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 539 KB
• Volume: 85
• Category: Article
• ISSN: 0167-9317
• DOI: 10.1016/j.mee.2007.12.046

✦ Synopsis

This paper presents the fabrication process of a SEPTIC (SEnsing of Phage-Triggered Ion Cascades) chip, consisting of two Ti contact pads and a 150 nm wide Ti nanowell device on LiNbO 3 substrate. The patterning was fulfilled by combining electron beam lithography, contact photolithography and reactive ion etching. When connected to an external preamplifier and spectrum analyzer, the nanowell can probe nano-scale electric field fluctuations. The use of this chip as nano-scale electric field probe was demonstrated by detecting the transitory ion efflux from bacteria being infected by phage. Our experiment showed that the electric field noise follows 1/f 2 power spectrum when the bacteria are sensitive to the phage, whereas 1/f noise corresponds to bacteria resistant to the phage. The use of fluctuation-enhanced sensing can provide sensitivity orders of magnitude higher than conventional sensing that detects changes only in the mean value of electrical signals.