Low-cost quantitative detection of nucleic acid using microbeads and microcolumn array chip

•A low-cost novel digital PCR method for nucleic acid quantification is developed.•Magnetic beads, microspheres and microcolumn array chips are used in our method.•No fluorophores or expensive instruments are required for our method.•A coupled Poisson distribution is used to predict the copy number of target DNA. High sensitive digital polymerase chain reaction (PCR) is one of the novel technology in molecular biology and has become more and more important in the arena of nucleic acid quantification. However, existing digital PCR technologies usually require specialized platform like high sensitive fluorescence microscope or flow cytometer, which has increased the detection costs and limited their further applications. Here we developed a simple and low cost nucleic acid quantification method based on beads, emulsion, amplification, and magnetics (BEAMing), microsphere and microcolumn array chip. We used the streptavidin (SA) modified polystyrene microspheres to capture the biotin covered target beads obtained via BEAMing technology, which could represent the population of target DNA. The microspheres-beads complexes were then collected and trapped in a microcolumn array chip and observed under a normal microscope. Because the number of microspheres-beads complexes had a relationship of coupled Poisson distribution with the number of target DNA, we could easily infer the number of target DNA through counting the number of chip-trapped microspheres. Our method has reduced the costs and lowers down the difficulty of digital PCR technology, which may promote the applications of digital PCR in research and clinical field.