Yan Li

Publications (3)11.61 Total impact

• Article: A novel sensing strategy for the detection of Staphylococcus aureus DNA by using a graphene oxide-based fluorescent probe.

  Shu Pang, Yuan Gao, Yan Li, Siyu Liu, Xingguang Su
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  ABSTRACT: A novel sensing strategy for sequence-specific recognition of Staphylococcus aureus (S. aureus) DNA was designed based on the DNA hybridization between dye-labeled single-stranded DNA (ssDNA) and the complementary target DNA. Graphene oxide (GO) can adsorb FITC-labeled probes and quench the fluorescence efficiently via Förster resonance energy transfer (FRET). However, the formation of double-stranded DNA (dsDNA) will alter the conformation of ssDNA and disturb the interaction between GO and ssDNA. Thus the dsDNA-GO mixture exhibits a stronger fluorescence emission than that of the ssDNA-GO mixture, and the relative fluorescence intensity ΔI/I0 (ΔI = Ia - Iq) is related to the concentration of ssDNA (S. aureus DNA). Here we illustrate a "post-mixing" strategy in which the fluorescent dye-labeled DNA was allowed to hybridize with S. aureus DNA prior to the addition of GO. In this experiment, the competition between ssDNA-GO adsorption and the dsDNA formation was avoided and the incubation time was shortened to 20 min. Under the optimum conditions, the relative fluorescence intensity ΔI/I0 was proportional to the concentration of S. aureus DNA in the range 0.0125-3.125 nmol L(-1), with a detection limit of 0.00625 nmol L(-1) and good sequence selectivity.
  The Analyst 03/2013; · 4.23 Impact Factor
• Article: Highly sensitive and selective detection of biothiols using graphene oxide-based "molecular beacon"-like fluorescent probe.

  Yuan Gao, Yan Li, Xin Zou, Hui Huang, Xingguang Su
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  ABSTRACT: A fluorometric method for quantity analysis of biothiols was developed using a graphene oxide (GO)-based "molecular beacon"-like probe, which consisted of FITC labeled thymine (T)-rich single-stranded DNA (ssDNA), GO and Hg(2+) ions. The labeled ssDNA containing T-T mismatches would self-hybridize to duplex in the presence of Hg(2+), which can avoid its adsorption on GO and the fluorescence of this GO-based probe was recovered. The fluorescence of the probe quenched after the addition of biothiols such as glutathione (GSH) and cysteine (Cys) owing to thiol groups can selectively competitive ligation of Hg(2+) ions with T-T mismatches. In the present work, the GO-based probe was used for the determination of GSH and Cys. Under the optimal conditions, a linear correlation was established between fluorescence intensity ratio I(0)/I and the concentration of GSH in the range of 2.0×10(-9)-5.0×10(-7) mol L(-1) with a detection limit of 1.0×10(-9) mol L(-1). The linear range for Cys is from 5.0×10(-9) to 4.5×10(-7) mol L(-1) with a detection limit of 2.0×10(-9) mol L(-1). The proposed method was applied to the determination of GSH in human serum and cell extract samples with satisfactory results.
  Analytica chimica acta 06/2012; 731:68-74. · 4.31 Impact Factor
• Article: Adsorption and removal of tetracycline antibiotics from aqueous solution by graphene oxide.

  Yuan Gao, Yan Li, Liang Zhang, Hui Huang, Junjie Hu, Syed Mazhar Shah, Xingguang Su
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  ABSTRACT: Significant concerns have been raised over pollution of antibiotics including tetracyclines in aquatic environments in recent years. Graphene oxide (GO) is a potential effective absorbent for tetracycline antibiotics and can be used to remove them from aqueous solution. Tetracycline strongly deposited on the GO surface via π-π interaction and cation-π bonding. The adsorption isotherm fits Langmuir and Temkin models well, and the theoretical maximum of adsorption capacity calculated by Langmuir model is 313 mg g(-1), which is approximately in a close agreement with the measured data. The kinetics of adsorption fits pseudo-second-order model perfectly, and it has a better rate constant of sorption (k), 0.065 g mg(-1) h(-1), than other adsorbents. The adsorption capacities of tetracycline on GO decreased with the increase in pH or Na(+) concentration. The adsorption isotherms of oxytetracycline and doxycycline on GO were discussed and compared.
  Journal of Colloid and Interface Science 11/2011; 368(1):540-6. · 3.07 Impact Factor