Objective  To study the DNA frequency shift signals of gold nanoparticles in mass amplified in piezoelectric DNA sensor.   Methods  The biotinylated target DNA after hybridation was labeled with 5 nm gold nanoparticles and colloidal gold to increase the mass load on the surface of quartz crystals by decreasing the response frequency of quartz crystals and further amplifying the frequency shift signals.   Results  The frequency shift signals of gold nanoparticles in the piezoelectric DNA sensor could be significantly amplified (P0.01) and the lowest rate of synthesized oligonucleotides detected with the sensor was 10

-12

mol/L.   Conclusion  The sensitivity of piezoelectric DNA sensor can be further improved by mass amplification. 