Publications by authors named "Hanmei Deng"

Article Synopsis
  • - A new polarity-reversal strategy is introduced for photoelectrochemical analysis to enhance sensitivity and accuracy by combining bipolar signal amplification.
  • - The study highlights the role of l-cysteine as a polarity regulator and a stable electron donor, which improves photocurrent performance compared to other common electron donors.
  • - The developed PEC biosensor shows remarkable sensitivity with a detection limit of 0.04 fM for lead ions and demonstrates potential applications in environmental monitoring and clinical diagnosis.
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Article Synopsis
  • Researchers have created a new method to improve the efficiency of DNA strand displacement reactions (SDRs) by using a combination of toehold initiators, strand towing, and click chemistry.
  • This innovative approach significantly speeds up the reaction and results in a six-fold increase in displacement rate compared to traditional methods.
  • The technique has been successfully integrated into a sensitive biosensing platform for detecting cancer-related miRNA-21, achieving a remarkably low detection limit, which could advance applications in medical diagnostics and DNA technology.
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Regulating photocurrent polarity is highly attractive for fabricating photoelectrochemical (PEC) biosensors with improved sensitivity and accuracy in practical samples. Here, a new approach that adopts the in situ generated AgI precipitate and AgNCs to reversal BiWO polarity with formation of Z-type heterojunction was proposed for the first time, which coupled with a high-efficient target conversion strategy of exonuclease III (Exo III)-assisted triple recycling amplification for sensing miRNA-21. The target-related DNA nanospheres in situ generated on electrode with loading of plentiful AgI and AgNCs not only endowed the photocurrent of BiWO switching from the anodic to cathodic one due to the changes in the electron transfer pathway but also formed AgI/AgNCs/Au/BiWO Z-type heterojunction to improve the photoelectric conversion efficiency for acquiring extremely enhanced PEC signal, thereby significantly avoiding the problem of high background signal derived from traditional unidirectional increasing/decreasing response and false-positive/false-negative.

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In this work, a high-performance conjugated microporous polymer (CMP) decorated with BiOBr (Tr(PhXOD)-CMP/BiOBr) is synthesized to application in construction of ultrasensitive photoelectrochemical (PEC) biosensor for sensing miRNA-122, by firstly coupling with efficient clip toehold-mediated allosteric bicycle strand displacement (ABSD). Notably, the Tr(PhXOD)-CMP/BiOBr not only owns self-enhanced D-A-D structure that extremely shortens migration distance of photo-generated electron, but also forms Z-type heterostructure for accelerating electron-hole separation, thereby significantly enhancing the photocurrent with 10-fold higher than commonly used methods. Meanwhile, the clip toehold-mediated ABSD based on ternary linkage structure transformation avoids the attrition of invading strand, endowing the conservation of high concentration for undergoing rapid reaction with high-efficiency DNA amplification, which dramatically improves reaction time and superior target conversion.

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Herein, a novel photocathodic nanocomposite poly{4,8-bis[5-(2-ethylhexyl)-thiophen-2-yl] benzo[1,2-:4,5-']dithiophene-2,6-diyl--3-fluoro-2-[(2-ethylhexyl)-carbonyl]thieno[3,4-]thiophene-4,6-diyl}/phthalocyanine zinc (PTB7-Th/ZnPc) with high photoelectric conversion efficiency under long-wavelength illumination was prepared to construct an ultrasensitive biosensor for the detection of microRNA-21 (miRNA-21), accompanied by a prominent anti-interference capability toward reductive substances. Impressively, the new heterojunction PTB7-Th/ZnPc nanocomposite could not only generate a strong cathodic photocurrent to improve the detection sensitivity under long-wavelength illumination (660 nm) but also effectively avoid the high damage of biological activity caused by short-wavelength light stimulation. Accordingly, by coupling with rolling circle amplification (RCA)-triggered DNA amplification to form functional biquencher nanospheres, a PEC biosensor was fabricated to realize the ultrasensitive analysis of miRNA-21 in the concentration range of 0.

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Photocathodic biosensor possesses excellent anti-interference capability in bioanalysis, which however suffers from high electron-hole recombination rate with low photocurrent. Herein, a high-performance inorganic organic PHT@C@ZnO nanosphere with cascade energy band arrangement was synthesized as photoactive signal probe, which inherited the advantages of inorganic strong optical absorptivity and organic high mobility for photo-generated holes. Specifically, the well-matched band gap endowed not only the improved life for light generated carrier and promoted separation of electron-hole pairs, but also the expansion of charge-depletion layer, significantly improving the photoelectric conversion efficiency for acquiring an extremely high photocathodic signal that increased by 30 times compared with individual materials.

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In this work, a novel reduction-accelerated quenching of manganese porphyrin (MnPP) based signal-off cathode photochemical (PEC) biosensor by using Au nano-flower/organic polymer (PTB7-Th) heterojunction as platform was proposed for ultrasensitive detection of Hg. Firstly, the photoactive PTB7-Th with Au nano-flower on electrode could form a typical Mott-Schottky heterojunction for acquiring an extremely high cathode signal. Meanwhile, the presence of target Hg could bring in the formation of T-Hg-T based scissor-like DNA walker, which thus activated efficient Mg-specific DNAzyme based cleavage recycling to shear hairpin H2 on electrode to exposure abundant trigger sites of hybridization chain reaction (HCR) for in-situ decoration of quencher MnPP.

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Photocathodic biosensor has great capability in anti-interference from reductive substances, however, the low signal intensity of photoactive species with inferior detection sensitivity restricts its wide application. In this work, the P3HT-PbS nanocomposites were synthesized as signal tags, by integrating with target-trigger generated hemin/G-quadruplex nanotail as bi-enhancer to significantly apmplify the photocurrent, an ultrasensitive photocathodic biosensor was proposed for detection of β2-microglobulin (β2-MG). Impressively, P3HT with cathode signal is an attractive polymer consisted of substantial thiophene groups with high absorption coefficient and mobility of photo-generated holes, which could anchor with the PbS dots as sensitizer, providing a high charge mobility and strong photosensitivity.

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In this work, a novel self-enhanced photoelectric active material, Na, K-codoped carbon nitride (NaKCN), was synthesized for constructing sensitive photoelectrochemical (PEC) biosensor to detect target miRNA-182-5p. Ingeniously, the NaKCN displayed glucose oxidase (GOx)-mimicking photocatalytic property, which catalyzed glucose to in situ generate high levels of HO as its own electron donor for enhancing photocurrent. Moreover, the Na, K co-doping could reduce energy gap of carbon nitride material, effectively improving the optical absorptivity and photocatalytic efficiency.

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Herein a photoelectrochemical (PEC) and electrochemical (EC) dual-mode biosensor with cationic ,-bis(2-(trimethylammonium iodide)propylene)perylene-3,4,9,10-tetracarboxydiimide (PDA)-decorated multifunctional DNA spheres in situ generated on an electrode was proposed for sensitive and accurate detection of miRNA-141. By employing a target-related ternary "Y" structure cleavage cycling reaction, the target DNA was converted into massive output DNA anchored on a TiO substrate, and hence triggering the rolling circle amplification (RCA) reaction. Upon addition of magnesium ions and PDA, the long DNA tails of the RCA product were condensed in situ to form multifunctional DNA spheres.

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A voltammetric biosensor for lead(II) (Pb) is described that is based on signal amplification by using an ion-dependent split DNAzyme and template-free DNA extension reaction. The Pb-dependent split DNAzyme was assembled on gold nanoparticles (Au@FeO), and this nanoprobe then was exposed to Pb which causes the split-off of DNAzymes to release primers containing 3'-OH groups (S and S). The template-free DNA extension reaction triggers the generation of long ssDNA nanotails, which then can bind the free redox probe N,N'-bis(2-(trimethylammonium iodide)propylene)perylene-3,4,9,10-tetracarboxyldiimide (PDA) via electrostatic adsorption.

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Photoelectrochemical (PEC) assay with low background, simple instrumentation and high sensitivity has deemed as one of the most potential strategies to simultaneous multi-component detection. How to distinguish photocurrent changes caused by various targets on a single sensing platform thus becomes the key issue to be resolved. Herein, we innovatively proposed a multiplex PEC biosensor based on wavelength distinguishable signal quenching and enhancing toward photoactive material 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) for simultaneous assay of dual metal ions.

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In this work, hydrazine-functionalized perylene diimide derivative supramolecular (HPDS), a novel self-enhanced donor-acceptor-donor (D-A-D) type aggregates with excellent photoelectric activity, was synthesized by a facile one-pot green route and further applied in construction of coreactant-free photoelectrochemical (PEC) biosensor for ultrasensitive DNA assay. Impressively, the HPDS formed by D-A-D units not only possessed effectively shorted electron-transfer path between donor and acceptor, but also presented a desiring aggregate state via the π-π stacking of perylene core and hydrogen bonding of the terminal moiety, thereby acquiring a high density electron flow for generating the extremely high PEC signal. Experimental data showed that the well film-formed HPDS aggregate could produce an exciting photocurrent intensity about 6-fold stronger than that of precursor perylene dianhydride with donor NH in detection buffer and even 12-fold than that of perylene dianhydride only.

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Herein, by utilizing bipedal DNA walker as booster to adjust the distance of quencher ferrocene (Fc) and sensitizer methylene blue (MB) to photoactive material perylene-3,4,9,10-tetracarboxylic acid (PTCA), a novel "on-off-super on" photoelectrochemical (PEC) biosensor was proposed for ultrasensitive detection of thrombin (TB). Firstly, the PTCA matrix on electrode could provide a high initial PEC signal assisted by depAu. Upon the Fc labeled on hairpin DNA 1 (H-Fc) proximate to PTCA, the PEC signal could obviously decrease to reduce the background signal.

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Here, with the target-catalyzed hairpin assembly generated dsDNA (HP1-HP2) to synchronously control the departure of quencher ferrocene and approach of sensitizer methylene blue, a distance-controllable multiple signal amplification based photoelectrochemical biosensor was proposed for MiRNA-21 assay.

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Herein, a novel signal-off photoelectrochemical (PEC) aptasensor was proposed for sensitive detection of thrombin on the basis of C@CN nanocomposites as quencher and Au nanoparticles (depAu) decorated perylene tetracarboxylic acid (PTCA) as sensing platform. Owing to the excellent membrane-forming of PTCA and superior conductivity of depAu, the PTCA between two depAu layers can simply and effectively produce an extremely high initial photocurrent to afford a precondition for sensitive biodetection. Thereafter, the assembly of C@CN nanocomposites on electrode via typical sandwich reaction enabled the generation of a significantly decreased photocurrent.

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In this work, a click reaction-triggered wavelength-resolved dual-signal output photoelectrochemical (PEC) biosensor with DNAzymes-assisted cleavage recycling amplification was proposed for sensitive triplex metal ions assay. Substantial DNA fragments azido-S and azido-S, derived from the Pb (target 1) and Mg (target 2) dependent cleavage cycle of DNAzymes, respectively, were grafted efficiently on the same alkynyl-DNA (capture DNA) modified electrode via the Cu (target 3) and ascorbic acid (AA) cocatalyzed click reaction, which thus could be subsequently used for immobilization of two different photoactive nanomaterials labeled with single DNA to generate distinguishing dual-signal output for simultaneously sensitive detection of Pb and Mg. Furthermore, the control variable method was used for detecting Cu by altering the concentration of Cu in the click reaction.

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Contamination from oil-field drilling waste is a worldwide environmental problem. This study investigated the performance of four bench-scale biopiles in treating drilling waste: 1) direct biopile (DW), 2) biopile plus oil-degrading microbial consortium (DW + M), 3) biopile plus microbial consortium and bulking agents (saw dust) (DW + M + BA), 4) biopile plus microbial consortium, bulking agents, and inorganic nutrients (Urea and K2HPO4) (DW + M + BA + N). Ninety days of biopiling removed 41.

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