Tang Meiling, Wen Guiqing, Luo Yanghe, Kang Caiyan, Liang Aihui, Jiang Zhiliang
Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection, Ministry of Education of China, Guangxi Normal University, Guilin, China.
Luminescence. 2015 May;30(3):296-302. doi: 10.1002/bio.2728. Epub 2014 Jul 3.
The substrate chain of double-stranded DNA (dsDNA) could be specifically cleaved by Pb(2+) to release single-stranded DNA (ssDNA) that adsorbs onto the AuPd nanoalloy (AuPdNP) to form a stable AuPdNP-ssDNA complex, but the dsDNA can not protect AuPdNPs in large AuPdNP aggregates (AuPdNPA) under the action of NaCl. AuPdNP-ssDNA and large AuPdNPA could be separated by centrifugation. On increasing the concentration of Pb(2+) , the amount of released ssDNA increased; AuPdNP-ssDNA increased in the centrifugation solution exhibiting a catalytic effect on the slow reaction of rhodamine 6G (Rh6G) and NaH2 PO2 , which led to fluorescence quenching at 552 nm. The decrease in fluorescence intensity (ΔF) was linear to the concentration of Pb(2+) within the range 0.33-8.00 nmol/L, with a detection limit of 0.21 nmol/L. The proposed method was applied to detect Pb(2+) in water samples, with satisfactory results.
双链DNA（dsDNA）的底物链可被Pb(2+)特异性切割，释放出单链DNA（ssDNA），ssDNA吸附到金钯纳米合金（AuPdNP）上形成稳定的AuPdNP-ssDNA复合物，但在NaCl作用下，dsDNA无法保护大尺寸金钯纳米合金聚集体（AuPdNPA）中的AuPdNP。通过离心可分离AuPdNP-ssDNA和大尺寸AuPdNPA。随着Pb(2+)浓度的增加，释放的ssDNA量增加；离心溶液中的AuPdNP-ssDNA增加，对罗丹明6G（Rh6G）与NaH2PO2的缓慢反应表现出催化作用，导致在552 nm处荧光猝灭。荧光强度的降低（ΔF）在0.33 - 8.00 nmol/L范围内与Pb(2+)浓度呈线性关系，检测限为0.21 nmol/L。该方法应用于水样中Pb(2+)的检测，结果令人满意。
