DNA Dipstick

Scientists have developed a cellulose dipstick that can purify DNA and RNA from a wide range of plant, animal and microbe samples within less than 30 seconds.


Researchers in Australia have developed a cellulose-based device that provides rapid nucleic acid purification in the field, potentially allowing low-cost molecular diagnostic assays in either plants or animals.

The report, titled “Nucleic acid purification from plants, animals and microbes in under 30 seconds,” is published in the online journal PLOS Biology.

The researchers note that nucleic acid amplification has proven to be indispensable in laboratories around the world for applications from diagnostics to genotyping. However, the process of extracting and amplifying DNA or RNA from complex biological samples requires expensive laboratory equipment, technicians and multiple steps. The group investigated various materials and discovered that cellulose-based filter paper -- Whatman No.1 paper – can rapidly bind and retain nucleic acids. Using that paper, they developed a “dipstick” that can purify nucleic acids from a wide range of plant, animal or microbe samples in less than 30 seconds. They also developed a simple washing process to remove PCR-inhibiting chemical/biological contaminants present in a plant crude extract while retaining enough DNA for amplification.

Following the one-minute wash, a user will transfer the sample to a PCR reaction tube, where it remains for PCR (polymerase chain reaction) analysis.

  1. their tests of the system, the researchers successfully detected the bacterial pathogen Pseudomonas syringae in Arabidopsis plants before disease symptoms were visible. They also successfully detected Actinobacillus pleuropneumoniae in a lung swab from an infected pig. To evaluate the system’s ability to extract RNA, and thus diagnose RNA-based pathogens, the researchers used the process to detect cucumber mosaic virus (CMV) in tomato plants.

The sampling process, using the Whatman No. 1 paper filter and other readily-available equipment, costs $0.15 or less per sample. The researchers note that common paper towels could be used in place of the filter paper, reducing the sample cost even more.