用硼氢化钠还原法制备了金硒(AuSe)纳米合金。 用单链核酸适配体(aptamer)修饰AuSe纳米合金制备了汞离子的核酸适配体纳米探针(Apta-AuSe)。 在pH 6.8 Na2HPO4-NaH2PO4缓冲溶液中及NaCl存在下, Apta-AuSe纳米探针亦不聚集； 当Hg2+存在时, 它可以稳定aptamer序列中的T-T错配, 形成较稳定的双链T-Hg2+-T错配物, 从而使释放出来的AuSe纳米合金聚集形成较大的微粒, 导致590 nm处共振散射峰增强。 Hg2+浓度在1.3～1 466 nmol·L-1范围内与共振散射光强度呈良好线性关系, 其回归方程和检出限分别为ΔI590 nm=0.603ｃ+2.0和0.74 nmol·L-1。 该方法用于水样中Hg2+的检测, 结果满意。

Under the condition of sodium citrate as stabilizer, the gold-selenium (AuSe) nano-alloy was prepared by sodium borohydride reduction procedure, and was modified by single-strand aptamer to obtain an aptamer nano-alloy probe (apta-AuSe) for Hg(Ⅱ). In pH 6.8 Na2HPO4-NaH2PO4 buffer solution and in the presence of NaCl of 33 mmol·L-1, the Apta-AuSe probe is not aggregation. The apta-AuSe interacts with Hg2+ to form stable double-strand T-Hg(Ⅱ)-T mismatches and to release AuSe nano-alloy particles from the probe. The released AuSe nano-alloy particles (20∶1) aggregated to form bigger clusters that resulted in the resonance scattering (RS) intensity (I590 nm) increasing at 590 nm. The increased intensity ΔI590 nm was proportional to the Hg2+ concentration from 1.3 to 1 466 nmol·L-1, with a detection limit of 0.74 nmol·L-1．The regress equation was ΔI590 nm=0.603ｃ+2.0. Thus, a new resonance scattering (RS) spectroscopy of apta-AuSe was applied to the analysis of trace mercury ion. This simple, rapid, selective and sensitive aptamer AuSe nano-alloy RS assay was applied to the determination of Hg2+ in wastewater, with satisfactory results.