Department of Applied Physics, Beihang University, Beijing, China.
Talanta. 2010 Jun 15;81(4-5):1810-5. doi: 10.1016/j.talanta.2010.03.046. Epub 2010 Mar 27.
The 5nm nanosilver was prepared by the sodium borohydride procedure, using sodium citrate as a stabilizing reagent. The nanosilver particle was combined with the aptamer for K(+) to form aptamer-nanosilver complex that was stabile in pH 7.0 Na(2)HPO(4)-NaH(2)PO(4) buffer solutions and in the presence of high concentration of NaCl. In 85 degrees C water bath, K(+) interacted with the aptamer to form very stable G-quadruplex that cannot stabilize the nanosilver particle. The uncombined nanosilver particles are aggregated to big particles in high concentration of NaCl, that led to the resonance scattering (RS) intensity at 470nm increased greatly. Under the selected conditions, the increased RS intensity (DeltaI) is linear to K(+) concentration in the range of 0.060-3350micromol/L, with a regression equation of DeltaI=0.177C+0.55, a correlation coefficient of 0.9964, and a detection limit of 0.006micromol/L K(+). The aptamer-nanosilver RS assay has been applied to determination of K(+) in serum and rain water, with satisfactory results.
5nm 纳米银通过硼氢化钠法制备，使用柠檬酸钠作为稳定剂。纳米银颗粒与 K(+) 的适配体结合，形成在 pH 7.0 的 Na(2)HPO(4)-NaH(2)PO(4)缓冲溶液和高浓度 NaCl 存在下稳定的适配体-纳米银复合物。在 85°C 水浴中，K(+)与适配体相互作用形成非常稳定的 G-四链体，不能稳定纳米银颗粒。未结合的纳米银颗粒在高浓度 NaCl 下聚集为大颗粒，导致在 470nm 处的共振散射（RS）强度大大增加。在选定的条件下，RS 强度（ΔI）在 0.060-3350μmol/L 范围内与 K(+)浓度呈线性关系，回归方程为ΔI=0.177C+0.55，相关系数为 0.9964，检测限为 0.006μmol/L K(+)。该适配体-纳米银 RS 测定法已应用于血清和雨水样品中 K(+)的测定，结果令人满意。
