In summary, a portable and sensitive quantitative detection of DNA based on personal glucose meters and isothermal circular strand-displacement polymerization reaction was developed. The target DNA triggered target recycling process, which opened capture DNA. The released target then found another capture DNA to trigger another polymerization cycle, which was repeated for many rounds, resulting in the multiplication of the DNA– invertase conjugation on the surface of Streptavidin-MNBs. The DNA–invertase was used to catalyze the hydrolysis of sucrose into glucose for PGM readout. A low limit of detection was obtained owning to following reasons: the amplification of target recycling process, the enrichment effect of Streptavidin-MNBs and the million turnovers of sucrose hydrolysis into glucose. In addition, the method exhibited excellent sequence selectivity, being able to differentiate a single mismatch in the target DNA. What is more,