Xue Gao

Jilin University, Yung-chi, Jilin Sheng, China

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Publications (12)43.79 Total impact

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    ABSTRACT: A new anticancer drug delivery system was developed based on the electrostatic complex of positively charged CuInS2 quantum dots (QDs) and negatively charged poly(l-glutamic acid) (PGA) conjugated with the model anticancer drug doxorubicin (DOX). Water-soluble near-infrared CuInS2 QDs capped with l-cysteine were directly synthesized by a hydrothermal method. DOX can quench the photoluminescence of CuInS2 QDs in QDs/PGA-DOX nanoparticles through a photoinduced electron transfer process, thus CuInS2 QDs are in the fluorescence "turn-off" state. After the QDs/PGA-DOX nanoparticles are exposed to carboxypeptidase or are taken up by cancer cells, PGA is hydrolysed to release DOX, inducing activation of the CuInS2 QDs fluorescence to the "turn-on" state. The QDs/PGA-DOX nanoparticles can deliver DOX to targeted cancer cells and monitor the DOX release based on the fluorescence "turn-on" signal of CuInS2 QDs, and this could be simultaneously used for the imaging of cancer cells. The multifunctional QDs/PGA-DOX nanoparticles have great potential in terms of their clinical application for cancer therapy.
    The Analyst 01/2014; · 4.23 Impact Factor
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    ABSTRACT: In this paper, near-infrared (NIR) fluorescent CuInS2 QDs@SiO2 nanobeads were prepared and used as fluorescent nanoprobes for prostate cancer cells imaging. The core–shell CuInS2 QDs@SiO2 nanobeads with controllable particle sizes were synthesized via a reverse microemulsion method. Further surface modifications were performed for grafting amino groups on the surface of the NIR CuInS2 QDs@SiO2 nanobeads. For prostate cancer cell imaging, anti-PSCA antibody was conjugated to the NIR CuInS2 QDs@SiO2 nanobeads to prepare the anti-PSCA–QDs@SiO2 nanoprobe. The specific binding of the antibody conjugated CuInS2 QDs@SiO2 nanobeads to the surface of human prostate cancer cells (PC-3M) was confirmed by fluorescence microscopy. MTT assay and fluorescence microscopy images showed that the anti-PSCA-conjugated NIR CuInS2 QDs@SiO2 nanoprobe was a non-toxic nanoprobe and had high-specificity in cell imaging. The CuInS2 QDs@SiO2 nanoprobe as an efficient NIR imaging nanoprobe could be used for target imaging, biological assays and early diagnosis of cancer.
    New Journal of Chemistry 12/2013; 38(1). · 3.16 Impact Factor
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    ABSTRACT: In this paper, Mn:ZnSe/ZnS core/shell-doped quantum dots (d-dots) with 3-mercaptopropionic acid as the stabilizer are successfully synthesized through a simple one-pot synthesis procedure in aqueous solution. The average diameter of Mn:ZnSe/ZnS core/shell d-dots is about 2.9 nm, which is lager than that of Mn:ZnSe cores (about 1.9 nm). The optical features and structure of the obtained Mn:ZnSe/ZnS core/shell quantum dots have been characterized by UV–Vis and fluorescence spectroscopy, X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. The photostability against UV irradiation and chemical stability against H2O2 etching have been studied, and the results showed that the prepared Mn:ZnSe/ZnS core/shell d-dots are more stable than CdTe quantum dots prepared in aqueous solution. Finally, the resulting core/shell quantum dots are used as fluorescent label in human osteoblast-like HepG2 cell imaging.
    Journal of Nanoparticle Research 06/2013; 15(6). · 2.18 Impact Factor
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    ABSTRACT: Quantum nanoparticles have been applied extensively in biological and medical fields, the cytotoxicity of nanoparticles becomes the key point we should concern. In this paper, the cytotoxicity of three kinds of water-soluble nanoparticles: CdTe, CdTe@SiO2 and Mn:ZnSe was studied. We evaluated the nanoparticles toxicity qualitatively by observing the morphological changes of human osteoblast-like MG-63 cells at different incubation times and colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assays were carried out to detect the cell viability quantitatively. The results showed that CdTe nanoparticles with high concentrations caused cells to die largely while CdTe@SiO2 and Mn:ZnSe nanoparticles had no obvious effect. For further study, we studied the relation between the cell viability and the total cadmium concentration in cells and found that the viability of cells treated with CdTe@SiO2 nanoparticles was higher than that treated with CdTe nanoparticles. We also discovered that the death rate of cells co-incubated with CdTe nanoparticles was proportional to the total intracellular cadmium concentrations.
    Materials Research Bulletin. 11/2012; 47(11):3654–3659.
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    ABSTRACT: This paper describes a novel, simple method for the highly sensitive and selective detection of thrombin using fibrinogen (Fib) and CuInS(2) quantum dots (QDs) as biosensing probes. Water-soluble near-infrared CuInS(2) QDs capped by mercaptopropionic acid (MPA) were directly synthesized by a hydrothermal method. Addition of fibrinogen to the CuInS(2) QDs solution led to the formation of a Fib-CuInS(2) QDs complex through electrostatic interactions and hydrogen bonding, and resulting in the enhancement of photoluminescence (PL) intensity and a red shift of the PL peak. Once thrombin was introduced into the Fib-CuInS(2) QDs system, it catalyzed the polymerization of the free and conjugated fibrinogen species to form insoluble fibrillar fibrin-CuInS(2) QDs agglutinates. After centrifugation, the PL intensity of the supernatants decreased upon increasing the concentration of thrombin. This Fib-CuInS(2) QDs probe provided a highly specific selectivity and a linear detection of thrombin in the range of 6.7 × 10(-11) to 3.9 × 10(-7) mol L(-1) with a detection limit (LOD) of about 8.7 × 10(-12) mol L(-1), and realized the thrombin detection in human serum samples directly. Compared with those obtained by using other nanomaterials and aptamer-based detection methods, this approach provided a lower LOD for thrombin detection. The proposed approach provides a simple and fast-responding procedure, which might hold a promising potential for application in the diagnosis of diseases associated with coagulation abnormalities and cancers.
    The Analyst 10/2012; · 4.23 Impact Factor
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    ABSTRACT: In this paper, a novel optical nanoprobe (Mn:ZnSe d-dots-Arg(6)) for trypsin detection and its inhibitor screening has been constructed successfully based on the fluorescence quenching and recovery of Mn:ZnSe d-dots. Mn:ZnSe d-dots would aggregate in the presence of positively charged Arg(6) (six arginine residues) due to electrostatic interactions that result in the fluorescence quenching. Arg(6) can be hydrolyzed into small fragments in the presence of trypsin, and accordingly, the aggregation of Mn:ZnSe d-dots can be prohibited, which lead to the fluorescence recovery. Experimental results show that the recovery in fluorescence intensity is linearly proportional to the concentration of trypsin within the range of 0.1-12.0 μg mL(-1) with a detection limit of 40 ng mL(-1) under the optimized experimental conditions. We also prove the feasibility of fluorescence recovery of Mn:ZnSe d-dots for trypsin detection through the resonance light scattering (RLS) technique. Additionally, the optical nanoprobe can be employed for screening the inhibitors of trypsin. The optical nanoprobe was successfully applied for the determination of trypsin in human serum and urine samples with good accuracy and satisfactory recovery.
    Analytica chimica acta 09/2012; 743:131-6. · 4.31 Impact Factor
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    ABSTRACT: In this paper, we report a sensitive and selective method for detection of organophosphorus compounds (OPs) based on Mn:ZnSe d-dots-enzyme-hydrogen peroxide (H(2)O(2)) fluorescence quenching system. Acetylcholine esterase (AChE) can hydrolyze acetylcholine (ACh) to choline. Subsequently, choline oxidase (ChOx) oxidizes choline to generate H(2)O(2). The enzyme-generated H(2)O(2) can quench the fluorescence of Mn:ZnSe d-dots. When paraoxon are introduced in solution, it can interact with the active centers of AChE and decrease the enzyme activity. This leads to the decrease of the H(2)O(2) production and then the fluorescence quenching rate of Mn:ZnSe d-dots. Experimental results showed that the enzyme inhibition percentage of Mn:ZnSe d-dots-ChOx-AChE-ACh system was proportional to the logarithm of paraoxon in the range 4.84×10(-11) to 4.84×10(-6) mol/L with the detection limit (S/N=3) of 1.31×10(-11) mol/L. The proposed biosensor has been employed for quick determination of paraoxon in tap water and milk samples with satisfactory reproducibility and accuracy. This nano-biosensor was proved to be sensitive, rapid, simple and tolerance of most interfering substances.
    Biosensors & Bioelectronics 04/2012; 36(1):75-80. · 6.45 Impact Factor
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    ABSTRACT: In this paper, we report the successful use of non-cadmium-based Mn-doped ZnSe d-dots (Mn/ZnSe) as highly efficient and nontoxic optical probes for human prostate cancer cells imaging. Mn/ZnSe d-dots are directly prepared in aqueous solution. The α-methylacyl-CoA racemase (AMACR) is overexpressed in prostate cancers; the presence of antibodies specific for AMACR is more sensitive and specific than serum prostate specific antigen levels in distinguishing patients with prostate cancers. Mn/ZnSe d-dots were linked to anti-AMACR to form Mn/ZnSe d-dots-anti-AMACR bioconjugates for the direct prostate cancer cell imaging. 3-(4,5-Dimethylthiazol-2-yl)-2 and 5-diphenyl tetrazolium bromide assay demonstrated that Mn/ZnSe d-dots exhibited favorable cytocompatibility to LNCaP cells with high concentration (1 mM) and long-time incubation (24 h). Furthermore, cellular imaging results demonstrated that Mn/ZnSe d-dots were remarkably efficacious for high-specificity cell imaging. The antibody-mediated delivery of the bioconjugates was further confirmed by the observation of no fluorescence signals in vitro targeting in nonprostate-cancer-based cell lines which are negative for AMACR. Mn/ZnSe d-dots as non-cadmium-based safe and efficient optical imaging nanoprobes could therefore be used for targeting imaging and treatment of cancers in the early stage.
    Analytical and Bioanalytical Chemistry 02/2012; 402(5):1871-7. · 3.66 Impact Factor
  • Xue Gao, Lu Niu, Xingguang Su
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    ABSTRACT: This manuscript reports a method for the detection of double-stranded DNA, based on Mn:ZnSe d-dots and intercalating agent doxorubicin (DOX). DOX can quench the photoluminescence (PL) of Mn:ZnSe d-dots through photoinduced electron transfer process, after binding with Mn:ZnSe d-dots. The addition of DNA can result in the formation of the Mn:ZnSe d-dots-DOX-DNA ternary complexes, the fluorescence of the Mn:ZnSe d-dots-DOX complexes would be further quenched by the addition of DNA, thus allowing the detection of DNA. The formation mechanism of the Mn:ZnSe d-dots-DOX-DNA ternary complexes was studied in detail in this paper. Under optimal conditions, the quenched fluorescence intensity of Mn:ZnSe d-dots-DOX system are perfectly described by Stern-Volmer equation with the concentration of hsDNA ranging from 0.006 μg mL(-1) to 6.4 μg mL(-1). The detection limit (S/N = 3) for hsDNA is 0.5 ng mL(-1). The proposed method was successfully applied to the detection of DNA in synthetic samples and the results were satisfactory.
    Journal of Fluorescence 08/2011; 22(1):103-9. · 1.79 Impact Factor
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    ABSTRACT: Quantum dots (QDs), also named semiconductor nanocrystals, have initiated a new realm of bioscience by combining nanomaterials with biology, which will profoundly influence future biological and biomedical research. In this review, we describe the extraordinary optical properties of QDs and developments in methods for their synthesis. We focus on fluorescent imaging with QDs both in vitro and in vivo, and the cytotoxicity of QDs and potential barriers to their use in practical biomedical applications. Finally, we provide insights into improvements aimed at decreasing the cytotoxicity of QDs and the future outlook of QD applications in biomedical fields.
    Analytical and Bioanalytical Chemistry 02/2010; 397(4):1397-415. · 3.66 Impact Factor
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    ABSTRACT: In this paper, the interaction of DNA molecules with aqueous CdTe quantum dots (CdTe QDs), CdTe/SiO(2) composite nanoparticles (CdTe/SiO(2) NPs), and Mn-doped ZnSe quantum dots (Mn:ZnSe d-dots) was studied with ethidium bromide as a probe. The purpose of this work was to study the damage of DNA molecules induced by these three kinds of water-soluble nanoparticles. It was found that ionic strength, pH value and UV irradiation influenced the PL emission properties of CdTe QDs, CdTe/SiO(2) NPs and Mn:ZnSe d-dots, and also influenced the interaction of DNA molecules with them. Among the three kinds of nanoparticles, DNA molecules were most easily damaged by CdTe QDs whether in the dark or under UV irradiation. The CdTe/SiO(2) NPs led to much less DNA damage when compared with CdTe QDs, as a silica overcoating layer could isolate the QDs from the external environment. Mn:ZnSe d-dots as a new class of non-cadmium doped QDs demonstrated almost no damage for DNA molecules, which have great potentials as fluorescent labels in the applications of biomedical assays, imaging of cells and tissues, even in vivo investigations.
    Talanta 01/2010; 80(3):1228-33. · 3.50 Impact Factor
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    ABSTRACT: In this paper, Mn2+-doped ZnSequantum dots (Mn:ZnSe d-dots) are synthesized successfully by a nucleation–doping method in aqueous solution with mercaptopropionic acid as the stabilizer. The optimal precursor ratio and kind of stabilizer for obtaining Mn:ZnSe d-dots with good photoluminescence emission properties was studied in detail. Finally, the photostability of the resulting Mn:ZnSe d-dots was studied and the results showed that Mn:ZnSe d-dots are much more photostable than CdTequantum dots synthesized in aqueous solution, indicating their potential as a new generation of fluorescent labels for biological assays, imaging of cells and tissues, even in vivo investigations.
    Journal of Materials Chemistry 01/2009; 19(38). · 6.63 Impact Factor