Accessible and affordable equipment-free nucleic acid purification, TropAg

November 5, 2019

The Crawford Fund’s Queensland Committee has again partnered with TropAg2019 to assist 10 young researchers from developing countries attend and present their science at this international conference which will be held in Brisbane from 11-13 November 2019. Successful candidates were chosen by a selection panel made up of representatives of The Crawford Fund and the TropAg2019 conference organisers, based on submitted abstracts of their research.

In the lead-up to the conference we will be publishing short blog posts written by the young researchers about their work. Here is the fourth blog.

By Yiping Zou, University of Queensland

Diagnosis is the critical first step for disease management. Nucleic acid-based diagnostic technologies are powerful due to their specificity and sensitivity. However, the major bottleneck preventing the widespread adoption of these technologies outside the laboratory environment at point-of-need (PON) is nucleic acid purification, a typically complicated, labour-intensive and time-consuming process. Current purification methods typically involve many sample manipulations and requires multiple pieces of equipment as shown in the left photo. Can you image nucleic acids now can be obtained by one dipstick and two solutions as shown in the right photo?

To achieve this, we investigated a variety of materials to test their ability in nucleic acid extraction. We found that untreated cellulose-based filter paper can bind DNA within seconds and retained sufficient DNA for amplification after washing step, while contaminations existing in biological samples were removed. Based on this knowledge, we created equipment-free nucleic acid extraction dipstick methodology that utilise dipstick containing cellulose-based nucleic acid binding area and a waterproof handle to extract nucleic acid by rapidly moving dipstick among extract, wash buffer and elution buffer successively. This method can obtain amplification-ready DNA or RNA from plants, animal, microbes or even difficult biological samples, such as mature tree leaves and human blood in less than 30 seconds. The simplicity, rapidness, low cost, availability of suitable material (e.g. common paper towelling) makes nucleic acid purification more accessible and affordable for researcher and the broader community.

The practicality of using the dipsticks to purify DNA at point of need has now been tested by our research group. The dipsticks have been successfully used in remote areas in Papua New Guinea, to rapidly extract DNA from coconut trees infected with ‘Bogia Coconut Syndrome’ (BCS), a disease that can rapidly spread and kill infected palms within six months, demonstrating the suitability of the dipstick for PON applications.