Paper-Based DNA Amplification Test to Simplify Infectious Disease Diagnostics

Pullulan is an edible, mostly tasteless polysaccharide polymer consisting of maltotriose units. The chief commercial use of pullulan is in the manufacture of edible films that are used in various breath freshener or oral hygiene products.

Rolling circle replication is a process of unidirectional nucleic acid replication that can rapidly synthesize multiple copies of circular molecules of DNA or RNA, such as plasmids, the genomes of bacteriophages, and the circular RNA genome of some viruses.

The RCA technique, which can produce massive DNA amplicons that can be easily visualized, was found to be more efficient in the paper matrix than in solution, which the investigators attributed to a significantly higher localized concentration of immobilized DNA.

The investigators developed a fully functional paper device for sensitive DNA or microRNA detection via printing of all RCA-enabling molecules within a polymeric sugar film formed from pullulan, which was integrated with the paper device. This encapsulation not only stabilized the entrapped reagents at room temperature but also enabled colorimetric bioassays with minimal steps.

“The new test involves printing of all required components needed to amplify a DNA or RNA target directly on paper,” said contributing author Dr. John Brennan, professor of chemistry at McMaster University. “The user only needs to add the sample to the paper and wait a few minutes for a color to develop.”

The RCA paper test was described in the January 8, 2016, online edition of the journal Angewandte Chemie.

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