摘要
在pH7.0的Na2HPO4-NaH2PO4缓冲溶液中,纳米金与适配体(aptamer)结合形成较稳定的aptamer-Au复合物,且不被NaCl聚集。在85℃水浴中,K+与aptamer作用后折叠形成稳定的G-四分体结构复合物且释放出纳米金。在高浓度盐作用下,纳米金聚集成较大粒径的纳米金颗粒,导致体系563nm处的共振散射强度增大,其平均粒径为120nm。文章研究了K+ -随机单链DNA1(ssDNA1)-纳米金、K+ -ssD-NA2-纳米金和K+ -aptamer-纳米金体系的共振散射光谱特性,并用圆二色光谱技术证明了核酸适配体结构的变化。考察了pH、NaCl浓度、aptamer浓度、纳米金用量以及Cu2+、Mg2+、Pb2+、Ca2+、Al3+、Zn2+Fe3+等常见重金属离子等对测定K+的影响,结果显示这些离子不干扰测定,该法具有较好的选择性。在选定条件下,K+浓度在0.67～3350μmol·L-1范围与共振散射峰值ΔI呈良好的线性关系,回归方程、相关系数、检出限分别为ΔI=0.167c-0.7,0.9932,0.3μmol·L-1 K+。该法用于血清样品分析,结果与离子选择电极法一致。
In pH 7.0 Na2HPO4-NaH2PO4 buffer solution,nanogold particles interacted with the aptamer to form a stable aptamer-nanogold complex that was not aggregation by NaCl.At 80℃,K＋ and aptamer folded to form a stable G-quadruplex that released nanogold particles,the uncombined nanogold particles aggregated to large nanogold clusters that caused the increase in resonance scattering（RS）intensity at 563nm in high concentration of NaCl,and the laser scattering showed that the average diameter was 120nm.In the present paper,the resonance scattering spectral characteristics of K＋-ssDNA1-Au,K＋-ssDNA2-Au and K＋-aptamer-Au systems were investigated,and the structural changes of aptamer were studied by circular dichroism spectral technology.Effects of pH value,NaCl concentration,nanogold concentration,aptamer concentration,and the reactation temperature and time on the resonance scattering intensity were considered in detail.The influence of coexistent substances on the determination of K＋ was investigated,result showed that the common heavy metal ions such as Cu2＋,Mg2＋,Pb2＋,Ca＋,Al 3＋,Zn2＋ and Fe3＋ do not interfere with the determination,and the method has good selectivity.Under the conditions selected,a 0.67-3 350μmol·L-1 K＋ can be detected by the aptamer-nanogold RS assay,with a detection limit of 0.3μmol· L-1 K＋,regression equation ΔI=0.167c-0.7,and a coefficient of 0.993 2.The method was used for analysis of K＋in serum sample with the results consistent with the ion-selective electrode method.
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2010年第11期3115-3118,共4页
Spectroscopy and Spectral Analysis
基金
国家自然科学基金项目(20965002
20865002
21075023)
广西自然科学基金项目(0991021Z
0832260)
广西环境工程与保护评价重点实验室项目资助
