Cellphone Camera Imaging of a Periodically Patterned Chip as a Potential Method for Point-of-Care Diagnostics
Abstract
In this study, we demonstrate that a disposable chip periodically patterned with, suitable ligands, an ordinary cellphone camera, and a simple pattern recognition software, can potentially be used for quantitative diagnostics. A key factor in this demonstration is the design of a calibration grid around the chip that, through a contrast transfer process, enables reliable analysis of the images collected under variable ambient lighting conditions. After exposure to a dispersion of amine terminated silica beads used as analyte mimicking pathogens, an epoxy-terminated glass substrate microcontact printed with octadecyltrichlorosilane (250 mu m periodicity) developed a characteristic pattern of beads which could be easily imaged with a cellphone camera of 3.2 MP pixels. A simple pattern recognition algorithm using fast Fourier transform produced a quantitative estimate of the analyte concentration present in the test solution. In this method importantly, neither the chip fabrication process nor the fill-factor of the periodic pattern need be perfect to arrive at a conclusive diagnosis. The method suggests a viable platform that may potentially find use in fault-tolerant and robust point-of-care diagnostic applications.
Keywords
cell phone camera, diagnostics, Fourier transformation, periodically patterned chip, pattern recognition, LABEL-FREE DETECTION, SOFT LITHOGRAPHY, REAL-TIME, SPORES, CELLS, PHONE
DOI
10.1021/am4050426
Date of this Version
3-26-2014
Recommended Citation
Gupta, Ritu; Reifenberger, Ronald G.; and Kulkarni, Giridhar U., "Cellphone Camera Imaging of a Periodically Patterned Chip as a Potential Method for Point-of-Care Diagnostics" (2014). Birck and NCN Publications. Paper 1576.
http://dx.doi.org/10.1021/am4050426