Dry-reagent nucleic acid biosensor based on blue dye doped latex beads and lateral flow strip

In the manuscript, a quantitative lateral flow nucleic acid biosensor (Lateral flow nucleic acid biosensor, LFNB) based on blue dye doped latex beads was proposed and its feasibility for detecting deoxyribonucleic acid (DNA) in plasma was investigated. A 60-mer DNA sequence (T1) was selected as model to demonstrate the protocol. Blue dyes doped latex bead bearing DNA probe would be captured on the corresponding test line in the presence of target DNA, to form an evident blue band. Although qualitative tests are realized by observing the color change of the test zone, quantitative data are obtained by recording the optical responses of the test zone with a portable "Strip Reader" instrument conveniently. The strip has been applied for the detection of synthesized DNA sample in human plasma sample with a detection limit of 3.75 fmol. Interference was not evident even the target DNA was spiked with 50 μL plasma which indicated the well shielding of the latex bead reporters and quantified chromatographic separations of unwanted materials of the strip comparing with traditional gold nanoparticle based LFNB platforms.