A simple, rapid, highly sensitive electrochem-ical sensor for potassium ion （K^＋） based on the confor-mationai change of DNA sequence containing guanine-rich segments is presented. In the presence of K^＋, guanine-...A simple, rapid, highly sensitive electrochem-ical sensor for potassium ion （K^＋） based on the confor-mationai change of DNA sequence containing guanine-rich segments is presented. In the presence of K^＋, guanine-rich DNA sequence folds to G-quadruplex structure, allowing a ferrocene tag to transfer electrons to the electrode. Gold nanoparticles （AuNPs）, which are self-assembled on the surface of a bare gold electrode by using 4-aminothio-phenol as a medium, offer a big surface area to immobilize a large number of aptamers and improve the sensitivity of the sensor. The square-wave voltammetry peak current increases with K^＋ concentration. The plots of peak current against K^＋ concentration and the logarithm of K^＋ con- centration are linear over the range from 0.1 to 1.0 mmol·L^-1 and from 1 to 30 mmol·L^-1, respectively. A lower detection limit of 0.1 mmol·L^-1 K^＋ is obtained for AuNPs-modified sensor, which greatly surpasses that （100 mmol·L^-1） of the sensor without AuNPs modification by three orders of magnitude. Thus, the sensor with AuNPs amplification is expected to open new opportunities for highly sensitive detection of other biomolecules in the future.展开更多
Uniform arrays of coarse and smooth gold nanoparticles with diameter about 130 nm were successfully synthesized through seed-mediated growth method, separately. Scanning and transmission electron microscopy （SEM and ...Uniform arrays of coarse and smooth gold nanoparticles with diameter about 130 nm were successfully synthesized through seed-mediated growth method, separately. Scanning and transmission electron microscopy （SEM and TEM） and X-ray diffraction （XRD） have been used to study the formation and structure of the nanocomposites. The high enhancement factor for surface-enhanced Raman scattering of coarse and smooth gold nanoparticles were estimated to be about 3.1 × 10^6 and 2.0 × 10^6, respectively. It is evident that the coarse gold nanostructures has higher influence factor than the smooth gold nanostructures. Therefore, these unique properties of the coarse Au nanoparticles appear to be very Dromising for applications as high-performance SERS subsrrares.展开更多
基金financially supported by the National Natural Science Foundation of China(No.20903008)
文摘A simple, rapid, highly sensitive electrochem-ical sensor for potassium ion （K^＋） based on the confor-mationai change of DNA sequence containing guanine-rich segments is presented. In the presence of K^＋, guanine-rich DNA sequence folds to G-quadruplex structure, allowing a ferrocene tag to transfer electrons to the electrode. Gold nanoparticles （AuNPs）, which are self-assembled on the surface of a bare gold electrode by using 4-aminothio-phenol as a medium, offer a big surface area to immobilize a large number of aptamers and improve the sensitivity of the sensor. The square-wave voltammetry peak current increases with K^＋ concentration. The plots of peak current against K^＋ concentration and the logarithm of K^＋ con- centration are linear over the range from 0.1 to 1.0 mmol·L^-1 and from 1 to 30 mmol·L^-1, respectively. A lower detection limit of 0.1 mmol·L^-1 K^＋ is obtained for AuNPs-modified sensor, which greatly surpasses that （100 mmol·L^-1） of the sensor without AuNPs modification by three orders of magnitude. Thus, the sensor with AuNPs amplification is expected to open new opportunities for highly sensitive detection of other biomolecules in the future.
基金financially supported by the National Basic Research Program of China(No.2010CB934700)the National Natural Science Foundation of China(Nos.51272012,21273001,51302208)+1 种基金Fundamental Research Funds for the Central Universities(No.YWF-14-HHXY-009)Specialized Research Fund for the Doctoral Program of Higher Education(No.20111102130006)
文摘Uniform arrays of coarse and smooth gold nanoparticles with diameter about 130 nm were successfully synthesized through seed-mediated growth method, separately. Scanning and transmission electron microscopy （SEM and TEM） and X-ray diffraction （XRD） have been used to study the formation and structure of the nanocomposites. The high enhancement factor for surface-enhanced Raman scattering of coarse and smooth gold nanoparticles were estimated to be about 3.1 × 10^6 and 2.0 × 10^6, respectively. It is evident that the coarse gold nanostructures has higher influence factor than the smooth gold nanostructures. Therefore, these unique properties of the coarse Au nanoparticles appear to be very Dromising for applications as high-performance SERS subsrrares.
