Portable and sensitive detection of DNA based on personal glucose meters and nanogold-functionalized PAMAM dendrimer

A simple, sensitive and portable biosensor for the detection of DNA based on the nanogold-functionalized poly(amidoamine) (PAMAM) dendrime composites and personal glucose meters (PGMs) was developed. In the presence of the target DNA, strand displacement reaction occurred between signal DNA and the target, inducing the release of invertase-DNA nanogold-functionalized PAMAM (IM-Au-PAMAM) from DNA-functionalized magnetic beads. The free IM-Au-PAMAM after magnetic separation finally acted as a highly efficient signal amplifier to catalyze the hydrolysis of sucrose into glucose for the readout of PGMs. The PGM signal intensity versus logarithm of DNA level was linear in the range from 0.5 pM to 1 nM. The detection limit for the target DNA sequence was 0.26 pM with good selectivity. Moreover, the new biosensor showed the advantages of cost-effectiveness, simplicity, portability, and convenience, and could be expected to be an emerging alternative for point-of-use detection of non-glucose targets.