Jianqing Liu

Jin-ai University, Fukou, Fujian, China

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Publications (4)14.05 Total impact

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    ABSTRACT: An inverse opal photonic crystal sensor that could specifically detect chloramphenicol (CAP) in a label-free way was introduced in the current research. A colloidal crystal template was first prepared from monodisperse SiO(2) nanospheres. Precursors with different compositions were infused into the void spaces of the respective templates and aggregated. The template and the imprinted CAP were removed, and a molecularly imprinted photonic polymer (MIPP) with numerous nanocavities derived from the SiO(2) template was prepared. The MIPP could specifically recognize the target CAP. The results showed that the embedding and transporting of CAP could change the reflection peak intensity of the MIPP. The MIPP exhibited good responsiveness, with a detection range from 1 ng mL(-1) to 1 μg mL(-1) of CAP. The MIPP response time was 8 min upon its addition to CAP at a concentration of 10 ng mL(-1), which is shorter than that of other methods. After repeated use, the MIPP maintained a good performance and detection capacity. Thus, the results prove that the novel sensor could specifically detect CAP in a simple, time-saving, and low-cost manner.
    The Analyst 08/2012; 137(19):4469-74. · 4.23 Impact Factor
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    ABSTRACT: A new suspension array technology is proposed for the simultaneous quantitative determination of four pathogens in food. Four sets of primers and species-specific capture probes were designed based on the 16S rDNA gene sequences of Escherichia coli, Staphylococcus aureus, Vibrio parahaemolyticus, and Salmonella downloaded from GenBank. The specific nucleic acid probes were covalently bound to the surface of fluorescent microspheres for liquid suspension hybridization. The biotin-labeled PCR products obtained from the samples were hybridized with their complementary nucleic acid probes, which were detected after the addition of streptavidin phycoerythrin. No cross-reaction occurred among the products, and the sensitivity of the probe in the single-channel method was 5 × 10−6 mM. In the multi-channel method, the sensitivities were as follows: 5 × 10−4 mM for E. coli and Salmonella, and 5 × 10−5 mM for S. aureus and V. parahaemolyticus. The multi-channel method achieved multidetection of several pathogens. For real sample detection, the methods showed a sensitivity of 103 CFU per g to 100 CFU per g of vegetables after enrichment for 24 h at 37 °C. This study demonstrates the utility of the suspension array specific for the 16S rDNA gene for determining the presence of the four pathogens in food samples.
    Analytical methods 07/2012; 4(8):2528-2536. · 1.86 Impact Factor
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    ABSTRACT: A new anticalin against estradiol (E(2)), a kind of endocrine disruptor, was obtained in the present study to detect E(2) levels. A member of the lipocalin family from Pieris brassicae called bilin-binding protein (BBP) was employed for the preparation of a random library to specifically complex E(2). Sixteen amino acid residues at the center of the binding site, which were formed by four loops on top of an eight-stranded β-barrel, were subjected to targeted random mutagenesis. Estradiol-binding BBP variants so-called 'anticalins', which exhibit binding activity for compounds, such as E(2), were selected from the resulting library by combining both ribosome display and screening techniques. Four variants of complex E(2) with high affinity were identified. These variants exhibited dissociation constants (KDs) as low as 54.265 nM. ELISA showed that ribosome displayed anticalin (E(2)-A) specifically bound E(2). The 50% inhibition concentration (IC(50)) for E(2) was 50 ng mL(-1) and the limit of detection (LOD:IC(10)) was 0.071 ng mL(-1). The experimental results suggest that E(2)-A can be used as a potential anticalin to detect E(2) in animals.
    The Analyst 04/2012; 137(10):2470-9. · 4.23 Impact Factor
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    ABSTRACT: Single chain variable fragments (scFvs) against diethylstilbestrol (DES) were selected from the splenocytes of non-immunized mice by ribosome display technology. A naive library was constructed and engineered to allow in vitro transcription and translation using an E. coli lysate system. Alternating selection in solution and immobilization in microtiter wells was used to pan mRNA-ribosome-antibody (ARM) complexes. After seven rounds of ribosome display, the expression vector pTIG-TRX containing the selected specific scFv DNAs were transformed into Escherichia coli BL21 (DE3) for expression. Twenty-six positive clones were screened and five clones had high antibody affinity and specificity to DES as evidenced by indirect competitive ELISA. Sequence analysis showed that these five DES-specific scFvs had different amino acid sequences, but the CDRs were highly similar. Surface plasmon resonance (SPR) analysis was used to determine binding kinetics of one clone (30-1). The measured K(D) was 3.79 µM. These results indicate that ribosome display technology can be used to efficiently isolate hapten-specific antibody (Ab) fragments from a naive library; this study provides a methodological framework for the development of novel immunoassays for multiple environmental pollutants with low molecular weight detection using recombinant antibodies.
    PLoS ONE 01/2012; 7(3):e33186. · 3.73 Impact Factor

Publication Stats

10 Citations
14.05 Total Impact Points

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Institutions

  • 2012
    • Jin-ai University
      Fukou, Fujian, China
    • Tianjin Institute of Health And Environmental Medicine
      T’ien-ching-shih, Tianjin Shi, China
    • Tianjin Medical University
      T’ien-ching-shih, Tianjin Shi, China