DNA detection using commercial mobile phones

This study investigates the feasibility of using mobile phones cameras for DNA detection. DNA amplification uses the convective polymerase chain reaction (cPCR) technique due to its simple mechanism, which requires no thermal cycling control. Fluorescence increment analysis and information entropy analysis are employed separately to determine whether the test samples contain target DNA (Positive) or not (Negative). The fluorescence increment method uses the brightness of the captured images before and after DNA amplification to calculate Delta F. Delta F values above a threshold level indicate that the test sample is positive. The information entropy method defines the probability, P(C/X), which indicates whether the fluorescence image tends towards a specific shape. If a DNA template is successfully amplified, the captured fluorescence image should be a perfect circle. P(C/X) provides a threshold of 0.5 to identify a circle and values above 0.5 indicate the test sample is positive. Experimental results show that P(C/X) is more effective than Delta F for determining DNA detection results. The information entropy analysis method is applied to ten mobile phones of three different brands equipped with camera sensors, which have pixel numbers ranging from 120 M to 800 M. The clinical evaluation study (n = 60) for screening hepatitis B virus (HBV) plasmid samples shows that the accuracy rate of all models of mobile phones ranges from 85% to 100%. This illustrates that successful DNA detection can be achieved using the most widely deployed electronic device. (C) 2011 Elsevier B.V. All rights reserved.