DNA imaging techniques using optical microscopy have found numerous applications in biology, chemistry and physics and are based on relatively expensive, bulky and complicated set-ups that limit their use to advanced laboratory settings. In this proposal timeline, we demonstrated imaging and length quantification of single molecule DNA strands using a compact, light-weight and cost-effective fluorescence microscope installed on a mobile-phone (see the Figures). In addition to an opto-mechanical attachment that creates a high contrast dark-field imaging set-up using an external lens, thin-film interference filters, a miniature alignment stage and a laser-diode for oblique-angle excitation, we also created a computational framework and a mobile-phone application that is wirelessly connected to a server for the measurement of the lengths of individual DNA molecules that are labeled and stretched using disposable chips. Using this mobile-phone platform, we imaged single DNA molecules of various lengths to demonstrate a sizing accuracy of <1 kilobase-pairs (kbp) for 10 kbp and longer DNA samples imaged over a large sample field-of-view of ~2 mm².

Through these results, we demonstrated a new milestone for cellphone based microscopy and sensing tools by single molecule fluorescent imaging and detection of DNA fragments using disposable chips. Until our recent results, this performance was out of reach for existing mobile-phone based imaging techniques, and will serve as the stepping stone to next-generation mobile micro-analysis, sensing and diagnostic tools and might also lead to single molecule DNA sequencing using mobile-phones. Furthermore, the same single molecule fluorescent imaging platform also permitted the accurate quantification of DNA length, which can be used for determining copy-number variations in genome through a field-portable and cost-effective mobile device – a capability that can be broadly used in various clinical applications including early detection of cancers (e.g., stomach, brain cancer etc.), nervous system disorders or even drug resistance in infectious diseases, including malaria. The latter is of paramount importance especially for global health problems, and might help us achieve early diagnosis of drug resistant malaria, assisting us to take appropriate measures earlier in the treatment process, potentially saving lives and avoiding waste of resources and medicines. Offering spatio-temporal data mapping, this single molecule DNA imaging and sizing platform could also assist e.g., health-care professionals, epidemiologists and policy makers, among others, to track emerging trends and shed more light on genetic cause-effect relationships in point-of-care and resource limited settings.

These results that we have got will also serve as our stepping stone to new landmarks for mobile imaging and diagnostic tools and their technical capabilities, shaping the future designs and digital components of mobile phones and other consumer electronics devices for use in next generation mobile-health and telemedicine technologies, also significantly impacting the future practices of preventive medicine.

Finally, this proposal also established a complementary educational outreach program which involved (1) public interviews and popular science articles in news media and internet; (2) undergraduate research opportunities in PI’s laboratory involving minority students; and (3) graduate student training through organization of workshops and seminars. Furthermore, research projects, seminars and open house visits served undergrads and high school students (especially from minority groups) to interact with a cutting edge research environment, helping to increase their scientific curiosity and shaping their career goals in science and engineering.

Last Modified: 12/21/2016
Modified by: Aydogan Ozcan