纳米金颗粒质量放大压电DNA传感器频移信号的研究

Frequency shift signals of gold nanoparticles in mass amplified piezoelectric DNA sensor

目的探讨纳米金颗粒质量放大压电DNA传感器频移信号的可行性,以进一步提高检测灵敏度。方法将巯基化的单链DNA探针固定于压电DNA传感器石英晶体金膜表面,封闭后加入合成的生物素化的互补靶DNA与之进行杂交反应,最后用5nm粒径的链亲和素标记的胶体金追加标记于杂交后的生物素化的靶DNA上,以增加石英晶振金膜表面的质量负载,从而降低石英晶振的响应频率,进一步放大频移信号。结果检测终浓度为10-8mol/L的阳性靶序列时杂交反应前后频移为(12.7±5.5)Hz,加入终浓度为9%的纳米金颗粒放大后总频移为(126±2.6)Hz,后者显著高于前者(P<0.01)。另外,对不同终浓度的阳性靶序列检测后发现,频移与其终浓度的lg值之间具有显著的线性关系,相关系数为0.974,而且最低检出限达到了10-12mol/L。结论实验结果表明该方法可以显著放大压电DNA传感器的频移信号,从而进一步提高压电DNA传感器检测的灵敏度。

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 （P〈0. 01） and the lowest rate of synthesized oligonueleotides detected with the sensor was 10^-12 mol/L. Conclusion The sensitivity of piezoelectric DNA sensor can be further improved by mass amplification.