Publications by authors named "Xiaolei Duan"

12 Publications

  • Page 1 of 1

A novel electrochemical biosensor based on peptidoglycan and platinum-nickel-copper nano-cube for rapid detection of Gram-positive bacteria.

Mikrochim Acta 2020 Oct 14;187(11):607. Epub 2020 Oct 14.

Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China.

A novel non-enzyme electrochemical biosensor for the rapid detection of Gram-positive bacteria has been constructed that relys on a stable and efficient combination between the peptidoglycan layer and platinum-nickel-copper nanocubes (Pt-Ni-Cu NCs). Briefly, bacteria were first captured by a specific antibody. Then, the electrochemical signal materials (Pt-Ni-Cu NCs) were bound to the bacteria peptidoglycan layer using specific structural and surface features. The rapid and sensitive bacterial detection was then achieved using intrinsic electrochemical characteristics and superoxidase-like activity of the Pt-Ni-Cu NCs. Moreover, the nature of peptidoglycan covering the whole bacteria provided the premise for signal amplification. Under optimal conditions, the electrochemical signal variation was proportional to the concentration of bacteria ranging from 1.5 × 10to 1.5 × 10 CFU/mL with a detection limit of 42 CFU/mL using a working potential of - 0.4 V. This electrochemical biosensor has been successfully applied to detect bacteria concentrations in urine samples, and the recoveries range from 90.4 to 107%. The proposed biosensor could be applied for broad-spectrum detection of Gram-positive bacteria since most Gram-positive bacteria possess a thick peptidoglycan layer. The developed electrochemical biosensing strategy might be used as a potential tool for clinical pathogenic bacteria detection and point-of-care testing (POCT).
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http://dx.doi.org/10.1007/s00604-020-04581-4DOI Listing
October 2020

Molybdenum [email protected] biosensor for unamplified specific fragment detection in long nucleic acids based on magnetic composite probe-actuated deblocking of secondary structure.

Anal Methods 2020 10;12(39):4813-4822

Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China.

Secondary structures in long circulating tumor nucleic acids have potential obstacles for specific location point hybridized detection of gene fragments. The exploration of biosensing strategies requires selectively changing the nucleic acids conformation and inducing signal switching. Herein, a self-assembled magnetic composite probe (MCP) was fabricated by the hybridization reaction of Linker DNA and a "Y"-junction-DNA nanostructure on the surface of magnetic beads, contributing to the capture, secondary structure unlocking, and enrichment of the PML/RARα DNA "L" subtype. Then, by integrating the MCP-actuated reactor, a one-step "off-on" signal switching [email protected] biosensing method was developed for the efficient detection of the PML/RARα DNA "L" subtype. The proposed biosensor was capable of detecting 100 bases PML/RARα DNA "L" subtype with a wide linear range of 1 pM to 200 nM and a limit of detection down to 0.223 pM without signal amplification. In addition, the biosensing method was successfully applied for the detection of target in serum samples. It is worth pointing out that this simple biosensing strategy could enable long nucleic acids fragments with secondary structures from ctDNA and ctRNA to be quantitatively assayed based on direct hybridization.
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http://dx.doi.org/10.1039/d0ay01398fDOI Listing
October 2020

High-sensitive and multiplex biosensing assay of NSCLC-derived exosomes via different recognition sites based on SPRi array.

Biosens Bioelectron 2020 Apr 28;154:112066. Epub 2020 Jan 28.

Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China. Electronic address:

Non-small cell lung cancer (NSCLC) have been reported to secret a high concentration of exosomes into blood circulatory system, which is one of sensitive and non-invasive biomarkers for NSCLC's early-stage diagnosis. But it is still lack of feasible and accurate methods to analyze the different NSCLC cells-derived exosomes. Herein, we built a SPRi biosensing assay for high-sensitive and multiplex characterizations of NSCLC-derived exosomes by bioaffinity interactions of antibodies and different recognition sites. By this way, the exosomes derived from normal lung and NSCLC cells can be effectively distinguished through precise identification of the exosomal protein pattern. And the multiplex characterizations of NSCLC-related exosomes are also achieved by anti-CD63, anti-EGFR and anti-EpCAM modified SPRi array. The limit of detection (LOD) of this SPRi-based biosensor approaches to the level of 10 particles/μL with the help of functionalized gold nanoparticles. Besides, the developed biosensing assay was successfully applied in the determination of exosomes purified from clinical plasma samples. This SPRi biosensing strategy might offer a potential alternative for massive high-throughput screening for NSCLC in clinical specimens.
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http://dx.doi.org/10.1016/j.bios.2020.112066DOI Listing
April 2020

Fiber optic surface plasmon resonance biosensor for detection of PDGF-BB in serum based on self-assembled aptamer and antifouling peptide monolayer.

Biosens Bioelectron 2019 Sep 25;140:111350. Epub 2019 May 25.

Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, PR China. Electronic address:

Herein, a home-build fiber optic surface plasmon resonance (FO-SPR) biosensing platform has been developed for highly sensitive detection of platelet-derived growth factor (PDGF-BB) based aptamer-functionalized AuNPs for signal enhancement. In this biosensor, the PDGF-BB aptamer was used to specifically capture PDGF-BB, and the antifouling peptide demonstrated great ability for resisting non-specific adsorption. After a sandwich reaction, the aptamer, PDGF-BB and aptamer-functionalized AuNPs complexes were formed on the fiber optic (FO) probe surface to significantly amplify FO-SPR signal. This method exhibited a broad detection range from 1 to 1000 pM of PDGF-BB and a low detection limit of 0.35 pM. Moreover, this biosensor was successfully applied to the detection of PDGF-BB in 10% human serum samples without suffering from serious interference owing to the excellent antifouling property of the peptide. Thus, this developed FO-SPR biosensor could be a potential alternative device for proteins determination, even as a point-of-care diagnostic tool (POCT) in clinical application.
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http://dx.doi.org/10.1016/j.bios.2019.111350DOI Listing
September 2019

Detection of KRAS mutation via ligation-initiated LAMP reaction.

Sci Rep 2019 04 11;9(1):5955. Epub 2019 Apr 11.

Department of Laboratory Medicine, The Affiliated Hospital of Zunyi Medical University, Zunyi, 563003, P.R. China.

KRAS mutations are abnormalities widely found in genomic DNA and circulating tumor DNA (ctDNA) of various types of cancers. Thus, highly sensitive detection of KRAS mutations in genomic DNA is of great significance in disease diagnosis and personalized medicine. Here, we developed a ligation-initiated loop-mediated isothermal amplification (LAMP) assaying method for ultrasensitive detection of KRAS mutation. In the presence of mutant KRAS DNA (mutDNA), the dumbbell-shaped structure (DSS) is formed by the specific ligation of two substrates (SLS1 and SLS2), which act as a template to initiate the following LAMP amplification. Making use of the outstanding specificity of ligation reaction and superior amplification of LAMP, 10 aM mutDNA can be accurately determined. In addition, as low as 0.1% mutDNA can be detected in the presence of a large excess of wild-type KRAS DNA (wtDNA), indicating the high sensitivity and specificity of the method. Furthermore, this strategy has been successfully applied for detection of a KRAS mutation from tissue samples of colorectal cancer patients. Thus, the developed ligation-initiated LAMP fluorescence assaying strategy presents a promising prospect for ultrasensitive detection of mutations.
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http://dx.doi.org/10.1038/s41598-019-42542-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6459849PMC
April 2019

Esthetic improvements of postorthodontic white-spot lesions treated with resin infiltration and microabrasion: .

Angle Orthod 2019 05 5;89(3):372-377. Epub 2019 Feb 5.

Objective: To compare the esthetic improvement between postorthodontic white-spot lesions (WSLs) treated by resin infiltration and microabrasion for 12 months.

Materials And Methods: A total of 20 patients with 128 teeth with postorthodontic WSLs were recruited. A simple randomized, split-mouth, positive controlled design was used to allocate patients to resin infiltration or microabrasion groups. The lesion area ratio (R value) was calculated between the area of a WSL and the labial surface of the corresponding tooth based on standardized clinical photographs. The color change (Δ) of each tooth was measured with a Crystaleye spectrophotometer (Olympus, Tokyo, Japan). Every measurement was taken before treatment (T0) and at different time points after treatment: 1 week (T1), 6 months (T6), and 12 months (T12).

Results: A total of 16 patients with 108 trial teeth were available at T12. Each group had 54 trial teeth. In both groups, there was a significant decrease in R value and Δ between T1 and T0 ( < .0001). In the infiltration group, the R value and Δ had no significant changes over time from T1 to T12. In the microabrasion group, the R value and Δ decreased significantly from T1 to T6. The R value of resin infiltration was lower when compared with microabrasion at every recall point ( < .001). The Δ had no significant differences between the two groups at any timepoint.

Conclusions: Resin infiltration and microabrasion improved the esthetic appearance of WSLs and showed sufficient durability for 12 months. Resin infiltration showed a better esthetic improvement effect when compared with microabrasion at 12 months.
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http://dx.doi.org/10.2319/041218-274.1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8117680PMC
May 2019

Monolayer rubrene functionalized graphene-based eletrochemiluminescence biosensor for serum cystatin C detection with immunorecognition-induced 3D DNA machine.

Biosens Bioelectron 2019 Feb 15;127:126-134. Epub 2018 Dec 15.

Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China. Electronic address:

Only surficial molecules of eletrochemiluminescent (ECL) nanomaterials are the most reactive species in the typical ECL reaction. Herein, monolayer rubrene was assembled on the surface of graphene sheet to obtain monolayer rubrene functionalized graphene composite (G/mRub) with strong ECL emission by maximizing the surficial rubrene molecules. Based on G/mRub as the strong ECL emitter, an ultrasensitive "on-off" biosensor was developed to detect cystatin C (Cys C) in human serum with the help of a novel immunorecognition-induced enzyme-free 3D DNA machine. Benefiting from the strong ECL emission of G/mRub and the efficient signal amplification of 3D DNA machine, the established biosensor achieved high sensitivity for Cys C detection with linear range from 1.0 fg mL to 10 ng mL and limit of detection down to 0.38 fg mL. In addition, this enzyme-free biosensing method was adopted to successfully detect the concentration of Cys C in human serum. Therefore, the G/mRub based ECL biosensor might provide a potential tool for protein detection in clinical diagnosis and a new avenue to prepare high-performance luminescent nanomaterials.
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http://dx.doi.org/10.1016/j.bios.2018.12.009DOI Listing
February 2019

A simple fluorescence biosensing strategy for ultrasensitive detection of the BCR-ABL1 fusion gene based on a DNA machine and multiple primer-like rolling circle amplification.

Analyst 2018 Oct;143(20):4974-4980

Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China.

A one-step, rapid fluorescence biosensing method has been developed for ultrasensitive detection of the BCR-ABL1 fusion gene based on a polymerase/nicking endonuclease DNA machine and multiple primer-like rolling circle amplification (RCA). In the strategy, the BCR-ABL1 fusion gene can be specifically identified by using a dual probe to form a three-way junction structure (3-WJ). Then the 3-WJ based DNA machine is driven by polymerase and nicking endonuclease to generate a large number of triggers, initiating a downstream RCA reaction. The introduction of two nicking endonuclease recognition sites into a circular DNA template makes RCA occur in a multiple primer-like manner, achieving exponential growth of the signal. Benefiting from the cascade amplification, the developed method generates a wide linear response from 10 fM to 1 nM with a low detection limit of 5.52 fM. In addition, the one-step operation allows the assay to be completed within 60 min and acceptable recovery is obtained in complex samples. These merits endow the biosensing strategy with certain potential for the clinical diagnosis and scientific research of the BCR-ABL1 fusion gene.
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http://dx.doi.org/10.1039/c8an01094cDOI Listing
October 2018

A highly sensitive SPRi biosensing strategy for simultaneous detection of multiplex miRNAs based on strand displacement amplification and AuNP signal enhancement.

Analyst 2018 Jun;143(13):3134-3140

Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China.

Herein, a dual channel surface plasmon resonance imaging (SPRi) biosensor has been developed for the simultaneous and highly sensitive detection of multiplex miRNAs based on strand displacement amplification (SDA) and DNA-functionalized AuNP signal enhancement. In the presence of target miRNAs (miR-21 or miR-192), the miRNAs could specifically hybridize with the corresponding hairpin probes (H) and initiate the SDA, resulting in massive triggers. Subsequently, the two parts of the released triggers could hybridize with capture probes (CP) and DNA-functionalized AuNPs, assembling DNA sandwiches with great mass on the chip surface. A significantly amplified SPR signal readout was achieved. This established biosensing method was capable of simultaneously detecting multiplex miRNAs with a limit of detection down to 0.15 pM for miR-21 and 0.22 pM for miR-192. This method exhibited good specificity and acceptable reproducibility. Moreover, the developed method was applied to the determination of target miRNAs in a complex matrix. Thus, this developed SPRi biosensing method may present a potential alternative tool for miRNA detection in biomedical research and clinical diagnosis.
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http://dx.doi.org/10.1039/c8an00549dDOI Listing
June 2018

An enzyme-free and label-free surface plasmon resonance biosensor for ultrasensitive detection of fusion gene based on DNA self-assembly hydrogel with streptavidin encapsulation.

Biosens Bioelectron 2018 Jul 14;112:120-126. Epub 2018 Apr 14.

Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China. Electronic address:

In this research, an enzyme-free and label-free surface plasmon resonance (SPR) biosensing strategy has been developed for ultrasensitive detection of fusion gene based on the heterogeneous target-triggered DNA self-assembly aptamer-based hydrogel with streptavidin (SA) encapsulation. In the presence of target, the capture probes (Cp) immobilized on the chip surface can capture the PML/RARα, forming a Cp-PML/RARα duplex. After that, the aptamer-based network hydrogel nanostructure is formed on the gold surface via target-triggered self-assembly of X shaped polymers. Subsequently, the SA can be encapsulated into hydrogel by the specific binding of SA aptamer, forming the complex with super molecular weight. Thus, the developed strategy achieves dramatic enhancement of the SPR signal. Using PML/RARα "S" subtype as model analyte, the developed biosensing method can detect target down to 45.22 fM with a wide linear range from 100 fM to 10 nM. Moreover, the high efficiency biosensing method shows excellent practical ability to identify the clinical PCR products of PML/RARα. Thus, this proposed strategy presents a powerful platform for ultrasensitive detection of fusion gene and early diagnosis and monitoring of disease.
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http://dx.doi.org/10.1016/j.bios.2018.04.027DOI Listing
July 2018

Collapse of DNA Tetrahedron Nanostructure for "Off-On" Fluorescence Detection of DNA Methyltransferase Activity.

ACS Appl Mater Interfaces 2017 Nov 13;9(46):40087-40093. Epub 2017 Nov 13.

Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University , Chongqing 400016, China.

As a potential detection technique, highly rigid and versatile functionality of DNA tetrahedron nanostructures is often used in biosensing systems. In this work, a novel multifunctional nanostructure has been developed as an "off-on" fluorescent probe for detection of target methyltransferase by integrating the elements of DNA tetrahedron, target recognition, and dual-labeled reporter. This sensing system is initially in an "OFF" state owing to the close proximity of fluorophores and quenchers. After the substrate is recognized by target methyltransferase, the DNA tetrahedron can be methylated to produce methylated DNA sites. These sites can be recognized and cut by the restriction endonuclease DpnI to bring about the collapse of the DNA tetrahedron, which leads to the separation of the dual-labeled reporters from the quenchers, and thus the recovery of fluorescence signal to produce an "ON" state. The proposed DNA tetrahedron-based sensing method can detect Dam methyltransferase in the range of 0.1-90 U mL with a detection limit of 0.045 U mL and shows good specificity and reproducibility for detection of Dam methyltransferase in a real sample. It has been successfully applied for screening various methylation inhibitors. Thus, this work possesses a promising prospect for detection of DNA methyltransfrase in the field of clinical diagnostics.
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http://dx.doi.org/10.1021/acsami.7b13551DOI Listing
November 2017

Effect and Stability of Poly(Amido Amine)-Induced Biomineralization on Dentinal Tubule Occlusion.

Materials (Basel) 2017 Apr 5;10(4). Epub 2017 Apr 5.

State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China.

In recent years, scientists have developed various biomaterials to remineralize human teeth to treat dentine hypersensitivity. Poly(amido amine) (PAMAM) dendrimers have become a research focus in this field. It has been demonstrated that PAMAM is able to create precipitates both on the surface of and within the dentinal tubules, however, there is little information about its effect on reducing dentine permeability in vitro. This study aimed to evaluate the in vitro effectiveness and stability of the fourth generation amine-terminated PAMAM on dentinal tubule occlusion, especially on dentine permeability. Sodium fluoride (NaF), which has been widely used as a desensitizing agent, is regarded as positive control. Demineralized sensitive dentine samples were coated with PAMAM or sodium fluoride solutions and soaked in artificial saliva (AS) at 37 °C for different periods. Four weeks later, samples in each group were then equally split into two subgroups for testing using a brushing challenge and an acid challenge. Dentine permeability of each specimen was measured before and after each challenge using a fluid filtration system. Dentine morphology and surface deposits were characterized by scanning electron microscope (SEM) and analyzed with Image-Pro Plus software. Data were evaluated through multifactorial ANOVA with repeated measures and pair-wise comparisons at a level of 5%. The results showed that PAMAM and NaF significantly reduced dentine permeability to 25.1% and 20.7%. Both of them created precipitates on dentine surfaces after AS immersion for 28 days. PAMAM-induced biomineralization not only on dentine surfaces, but also deeper in dentinal tubules, significantly reduced dentine permeability. Moreover, PAMAM-induced biomineralization elicited excellent stable occlusion effects after acid challenge. In conclusion, PAMAM demonstrated a strong ability to resist acid and showed great potential to be used in the treatment of dentine hypersensitivity in future.
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http://dx.doi.org/10.3390/ma10040384DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5506945PMC
April 2017