Jump to main content
Jump to site search

Issue 11, 2013
Previous Article Next Article

Label-free biodetection using a smartphone

Author affiliations

Abstract

Utilizing its integrated camera as a spectrometer, we demonstrate the use of a smartphone as the detection instrument for a label-free photonic crystal biosensor. A custom-designed cradle holds the smartphone in fixed alignment with optical components, allowing for accurate and repeatable measurements of shifts in the resonant wavelength of the sensor. Externally provided broadband light incident upon an entrance pinhole is subsequently collimated and linearly polarized before passing through the biosensor, which resonantly reflects only a narrow band of wavelengths. A diffraction grating spreads the remaining wavelengths over the camera's pixels to display a high resolution transmission spectrum. The photonic crystal biosensor is fabricated on a plastic substrate and attached to a standard glass microscope slide that can easily be removed and replaced within the optical path. A custom software app was developed to convert the camera images into the photonic crystal transmission spectrum in the visible wavelength range, including curve-fitting analysis that computes the photonic crystal resonant wavelength with 0.009 nm accuracy. We demonstrate the functionality of the system through detection of an immobilized protein monolayer, and selective detection of concentration-dependent antibody binding to a functionalized photonic crystal. We envision the capability for an inexpensive, handheld biosensor instrument with web connectivity to enable point-of-care sensing in environments that have not been practical previously.

Graphical abstract: Label-free biodetection using a smartphone

Back to tab navigation
Please wait while Download options loads

Supplementary files

Publication details

The article was received on 29 Aug 2012, accepted on 03 Apr 2013, published on 03 Apr 2013 and first published online on 03 Apr 2013


Article type: Paper
DOI: 10.1039/C3LC40991K
Citation: Lab Chip, 2013,13, 2124-2132
  •   Request permissions

    Label-free biodetection using a smartphone

    D. Gallegos, K. D. Long, H. Yu, P. P. Clark, Y. Lin, S. George, P. Nath and B. T. Cunningham, Lab Chip, 2013, 13, 2124
    DOI: 10.1039/C3LC40991K

Search articles by author