Diffraction-Based Cell Detection Using a Microcontact Printed Antibody Grating

Pamela M. St. John, Robert Davis, Nathan Cady, John Czajka, Carl A. Batt, Harold G. Craighead

Research output: Contribution to journalArticlepeer-review

145 Scopus citations


An optical detector has been fabricated that is specific for targeted bacterial cells, by stamping an antibody grating pattern on a silicon surface. The antibody grating alone produces insignificant optical diffraction, but upon immunocapture of cells, the optical phase change produces a diffraction pattern. This technique eliminates much of the surface modifications and the secondary immunochemical or enzyme-linked steps that are common in immunoassays. Microcontact printing provides an alternative to previously reported photolithographic-mediated antibody patterning processes and uses a photolithographic process simply to produce the elastomeric stamp. We have stamped antibodies directly onto clean native oxide silicon substrates with no other chemical surface treatments. Direct binding of the antibodies to the silicon occurs in a way that still allows them to function and selectively bind antigen. The performance of the sensor was evaluated by capturing Escherichia coli 0157:H7 cells on the antibody-stamped lines and measuring the intensity of the first-order diffraction beam resulting from the attachment of cells. The diffraction intensity increases in proportion to the cell density bound on the surface.

Original languageEnglish (US)
Pages (from-to)1108-1111
Number of pages4
JournalAnalytical Chemistry
Issue number6
StatePublished - Mar 15 1998

ASJC Scopus subject areas

  • Analytical Chemistry


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