On-line Cu （II） ion concentration detection in bioleaching system was achieved by anodic stripping differential pulse voltammetry （ASDPV）. Good linearity between Cu （II） concentration and oxidation peak current was obtained when Cu （II） existed in 0K media in the concentration range of 1μmol/L （64μg/L） to 1 mmol/L （64 mg/L）. Moreover, when 0.2 mol/L KCl was added into this media, the linear detection range could be extended from 1 mmol/L to 100 mmol/L （6.4 g/L）. The reduction of Cu （II） to metallic copper was shown to proceed as two successive single-electron transfer reactions involving an intermediate chemical step where the cuprous ion （Cu＋） was complexed by chloride to form the dichlorocuprous anion （CuCl-）. In addition, interference effect was also investigated when Fe3＋existed in the media, which was the common situation in the copper bioleaching system. The results showed no interference effect once the concentration of Fe3＋was less than 100 mmol/L （5.6 g/L）.
In the present study, we developed a highly sensitive and convenient biosensor consisting of gold nanoparticle （AuNP） probes and a gene chip to detect microRNAs （miRNAs）. Specific oligonucleotides were attached to the glass surface as capture probes for the target miRNAs, which were then detected via hybridization to the AuNP probes. The signal was amplified via the re- duction of HAuCI4 by H202. The use of a single AuNP probe detected 10 pmol L-1 of target miRNA. The recovery rate for miR-126 from fetal bovine serum was 81.5%-109.1%. The biosensor detection of miR-126 in total RNA extracted from lung cancer tissues was consistent with the quantitative PCR （qPCR） results. The use of two AuNP probes further improved the de- tection sensitivity such that even 1 fmol L-t of target miR-125a-5p was detectable. This assay takes less than 1 h to complete and the results can be observed by the naked eye, The platform simultaneously detected lung cancer related miR-126 and miR-125a-5p. Therefore, this low cost, rapid, and convenient technology could be used for ultrasensitive and robust visual miRNA detection.
为了实现对核酸的高灵敏度检测,构建了一种新型的液滴式数字聚合酶链式反应(dd PCR)芯片.该芯片由产生液滴的聚二甲基硅氧烷(PDMS)模块和储存液滴的玻璃腔室构成.实验结果表明,该芯片可以在25 min内产生2×106个直径为20μm的微液滴(体积4.187 p L).利用该芯片定量检测了表皮生长因子受体(EGFR)基因第19号外显子,在DNA浓度为106~101copies/μL范围内呈现良好的线性关系(R2=0.9998);在浓度为106copies/μL的19号外显子野生型DNA中检测105~100copies/μL的突变型DNA,其检测敏感度可达到0.0001%.该方法在同一芯片上实现了液滴产生、核酸扩增和荧光信号读取的功能,在核酸绝对定量及痕量突变基因的检测中具有潜在应用前景.
