非标记纳米银探针催化共振散射光谱检测痕量ATP

Nanocatalytic Resonance Scattering Spectral Detection of Trace ATP Using Labeled-free Nanosilver as Probe

在pH 7.8 Tris-HCl缓冲液中,三磷酸腺苷(adenosine triphosphate,ATP)的核酸适体(Apt 1)与其互补链(Apt 2)结合生成双链DNA(double-strand DNA,dsDNA).此dsDNA不能稳定纳米银(AgNP),NaCl可致AgNP聚集,在500 nm波长处产生一个较强的共振散射峰.加入ATP后,ATP与dsDNA中的Apt 1结合形成较稳定的发夹结构结合物并释放出可稳定AgNP的Apt 2.随着ATP浓度(16.5～1650 nmol/L)增加,生成的Apt 2增加,被Apt 2稳定的AgNP即AgNP-Apt 2结合物增加,聚集的AgNP减少,500 nm处的共振散射值线性减小.该适配体反应中的AgNP-Apt 2对葡萄糖-铜(II)微粒反应具有较强的催化作用,其产物氧化亚铜微粒在610 nm处有一较强共振散射峰.随着ATP浓度增大,反应液中AgNP-Apt 2增多,催化作用增强,610 nm处的共振散射峰增强.ATP浓度在4.95～165 nmol/L范围内与共振散射增大值ΔI610 nm呈线性关系,检出限为1.8 nmol/L ATP.据此建立了灵敏度高、选择性好、简便快速检测ATP的共振散射光谱新方法.

In pH 7.8 Tris-HCl buffer solution,the aptamer（Apt 1） combined with its complementary ap-tamer（Apt 2） to form double-strand DNA（dsDNA） that can not protect nanosilver（AgNP）.Under the action of NaCl,the AgNP particles were aggregated to large particles that exhibited a resonance scattering peak at 500 nm.Upon addition of adenosine triphosphate（ATP）,it reacted with the Apt 1 of dsDNA to produce sta-ble ATP-Apt 1 conjugate,and the released Apt 2 combined with AgNP to form stable AgNP-Apt 2 conjugate.When ATP concentration increased from 16.5 to 1650 nmol/L,the stable AgNP-Apt 2 increased,and the ag-gregated AgNP decreased.Thus,the RS intensity at 500 nm decreased linearly.Results showed that the AgNP-Apt 2 exhibited strong catalytic effect on the Cu2O particle reaction between glucose and Cu（II）,and the product of Cu2O particles appeared a RS peak at 610 nm.When ATP concentration increased,the AgNP-Apt 2 increased,the RS intensity at 610 nm enhanced linearly.The enhanced RS intensity was linear to ATP concentration in the range of 4.95～165 nmol/L,with a detection limit of 1.8 nmol/L ATP.Thus,a highly sensitive,selective and simple RS assay was proposed for ATP.