Lab Chip http://dx.doi.org/10.1039/C3LC50707F (2013)

Frederik Colle and colleagues in Belgium have demonstrated a rapid and sensitive lens-free imaging technique for lab-on-chip analysis of nucleic acids. The optomagnetic approach allows detection of DNA fragments that have been labelled with magnetic particles. First, external magnets are used to attract magnetic particles towards a functionalized surface, where they bind to and label DNA. Next, other sets of magnets above the surface are used to remove unbound particles from the field of view during lens-free imaging, which is performed using partially coherent illumination from a light-emitting diode. The interference patterns obtained are reconstructed using software. This method reportedly allows DNA fragment detection at a concentration range down to 10 pM. It offers high sensitivity, and requires minimal hardware and a low computing power, thus making it promising for realizing a compact, inexpensive device for point-of-care DNA quantification.