Paper-based rapid detection of pork and chicken using LAMP-magnetic bead aggregates

Magnetic beads (MBs) have been widely used for DNA quantification. In the presence of a magnetic field, DNA and MBs form aggregates that can be visualized by the naked eye on filter paper. The aim of this study was to develop a sequence-specific and simple method for the detection of different types of meat using isothermal loop mediated amplification (LAMP) and MB-mediated aggregation. Sequence specific primers were first designed to detect the targeted meat types (chicken and pork). Following LAMP amplification, the MBs were added to the LAMP products. These produced aggregates showed up as dark spots on filter paper. In contrast, stable aggregates did not form in the absence of LAMP products. Optical images of the aggregates could be used for the simple detection of the DNA. This method could detect genomic DNA at low picogram levels (chicken 1 pg mu L-1 and pork 100 pg mu L-1). The protocol allowed the detection of LAMP products starting from 20 min of amplification, which is time effective compared with the conventional methods. In addition, this method of DNA quantification is label-free and very sensitive. Because it does not require heavy or expensive instruments, this method could be applied in biosensors, the biomedical field, and molecular diagnostics.