Publications by authors named "Junqiu Zhai"

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a highly toxic persistent organic pollutant (POP) that can induce DNA damage within cells. Although oxidative stress is one of the primary mechanisms causing DNA damage, its role in the process of TCDD-induced DNA damage remains unclear. In this study, the TCDD-induced production of reactive oxygen species (ROS) and the occurrence of DNA damage at the AP site were monitored simultaneously.

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Helicases are crucial enzymes in DNA and RNA metabolism and function by unwinding particular nucleic acid structures. However, most convenient and high-throughput helicase assays are limited to the typical duplex DNA. Herein, we developed an immunosorbent assay to monitor the Werner syndrome (WRN) helicase unwinding a wide range of DNA structures, such as a replication fork, a bubble, Holliday junction, G-quadruplex and hairpin.

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Pollutant exposure causes a series of DNA damage in cells, resulting in the initiation and progression of diseases and even cancers. An investigation of the DNA damage induced by pollutants in living cells is significant to evaluate the cytotoxicity, genotoxicity, and carcinogenicity of environmental exposure, providing critical insight in the exploration of the etiologies of diseases. In this study, we develop a repair enzyme fluorescent probe to reveal the DNA damage caused by an environmental pollutant in living cells by single-cell fluorescent imaging of the most common base damage repair enzyme named human apurinic/apyrimidinic endonuclease 1 (APE1).

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There is an urgent demand for non-invasive and high compliance delivery systems of macromolecules for long-term therapy. However, oral administration of macromolecules is hindered by low permeability and instability in the gastrointestinal (GI) tract. Therefore, we developed a novel aptamer-modified liposomes (Apt-Lip) with M cell targeting for oral delivery of exenatide (EXT).

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The generation of singlet oxygen (O) using photodynamic therapy (PDT) is limited by the hypoxia of the tumor microenvironment and the depth of external light penetration because it depends on the precise cooperation between the photosensitizers, oxygen, and light. Herein, we report a self-sufficient O nanoreactor with enhanced penetration into deep tumors for cancer therapy. Linoleic acid hydroperoxide (LAHP) is coordinated with transition metal ions (Cu/Fe) to prepare linoleic acid hydroperoxide metal complex nanoparticles (LAHP-M NPs).

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Article Synopsis
  • In situ imaging of DNA repair enzymes like APE1 in living cells can help diagnose and understand diseases, and using fluorescent probes offers sensitive, real-time detection despite challenges in their design and optimization.* -
  • The study combines experimental approaches with molecular simulations, specifically utilizing Extended-system Adaptive Biasing Force (eABF) to design a new sensitive fluorescent DNA probe (Nanoprobe N) that overcomes limitations of existing probes.* -
  • The newly designed nanoprobe demonstrates high sensitivity with a detection limit of 0.5 U/L, effectively differentiating cancer cells from normal cells, showcasing the potential of this method for precise imaging and screening at the single-cell level.*
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A core-shell molecularly imprinted polymer nanoparticle with biological enzyme functional characteristics was developed by oxidative polymerization of template protein and polydopamine on the surface of protease-copper phosphate hybrid nanoflowers by molecular imprinting technology and enzyme immobilization technology. The obtained molecularly imprinted polymer showed specific binding characteristics with the template protein. It recognized and enriched the target molecules through the surface molecularly imprinted sites of the shell structure.

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The integration of reactive oxygen species (ROS)-involved molecular dynamic therapy (MDT) and photodynamic therapy (PDT) holds great promise for enhanced anticancer effects. Herein, we report a biodegradable tumor microenvironment-responsive nanoplatform composed of sinoporphyrin sodium (SPS) photosensitizer-loaded zinc peroxide nanoparticles (SPS@ZnO NPs), which can enhance the action of ROS through the production of hydrogen peroxide (HO) and singlet oxygen (O) for MDT and PDT, respectively, and the depletion of glutathione (GSH). Under these conditions, SPS@ZnO NPs show excellent MDT/PDT synergistic therapeutic effects.

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The glucagon-like peptide-1 receptor agonist exenatide (EXT) is an effective treatment for type 2 diabetes. However, this peptide has a short biological half-life and the delayed release characteristic of current formulations limit its clinical application. Herein, we prepared EXT-loaded inside-porous poly(d,l-lactic-co-glycolic acid (PLGA) microspheres with outside layers (EXT-PMS) using a W/O/W emulsion method with a microfluidic technique and its fabrication and formulation conditions were systematically investigated.

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Curcumin (CUR) has attracted wide research interests due to its abundant bioactivities and potential advantages in cancer treatment. But the poor water solubility, instability, and quick metabolization and elimination after oral administration severely restrict the efficacy and further clinical application of CUR. Derivation is an approach often used to improve the druggability of active ingredients, so the study aim to prepare a CUR derivate with better stability, satisfactory pharmacokinetics, and inherent self-assembled ability in contrast with CUR.

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Schizophrenia and bipolar disorder are severe chronic neuropsychiatric diseases, affecting hundreds of millions of people worldwide. Asenapine maleate (ASM) has been demonstrated as a safe and effective therapeutic agent under twice-daily administration. However, lower compliance is observed when patients are treated with ASM, which significantly limits its application in schizophrenia and bipolar disorder.

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Combinational administration of photothermal therapy (PTT) and chemotherapy (CT) shows great potential in improving the efficiency of tumor treatment. Herein, we designed a novel nanocomposite Pt@BiTe composed of bismuth telluride (BiTe) nanoparticles and platinum(IV) prodrugs (Pt) for PTT-CT combination therapy. The obtained BiTe was synthesized by a simple solvothermal method and modified by polyethylene glycol, which exhibited excellent photothermal (PT) efficiency and stability and could also serve as a bimodal bioimaging contrast agent in PT and photoacoustic (PA) imaging.

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Curcumin (CUR) possesses photosensitive anti-tumor activity. However, photoactive CUR mainly targets tumor cells sensitive to chemotherapy, whereas the effect on multi-drug resistant cancer cells has not been fully investigated. The study aimed to investigate the anti-tumor activity of CUR on resistant MCF-7/ADM cells and its underlying mechanism providing insights into CUR-mediated PDT and a reference for reversing multidrug resistance.

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Progesterone (PG) is an essential sex hormone with a variety of important biological functions, but its insolubility leads to low bioavailability of most water-based formulations. What is more, the commercial oil-based formulations often cause severe side effects after long-term injection due to poor tissue absorption of oil. Herein, we report an aseptic bottom-up method utilizing emulsion freeze-drying technology that produces size-controllable, highly bioavailable, and water-based PG nanocrystal injection.

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A bionanocomposite with artificial binding pockets for a DNA repair enzyme has been developed by in situ assembly of an affinity protein with a surrounding contact surface of polydopamine on the surface of silica coated magnetic nanoparticles via molecular imprinting reactions. The obtained nanoparticles exhibited antibody-like binding behavior toward the target enzyme with highly specific and efficient inhibition effect. Moreover, the binding and inhibition could be flexibly tuned by the addition of metal ions such as Mn and Mg, which provided a convenient tool to regulate enzyme activity with artificially engineered nanoinhibitors.

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Human apurinic/apyrimidinic endonuclease/redox effector factor 1 (APE1) is an essential DNA repair protein. Herein, we demonstrate that avidin-oriented abasic site-containing DNA strands (AP-DNA) on the surface of silica coated magnetic nanoparticles (SiMNP) can selectively respond to APE1 while resist the digestion by other nucleases. Mechanism studies have revealed that avidin may serve as an organizer protein and recruit APE1 to the DNA substrates on the nanoparticles via strong and specific interactions.

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We demonstrate the successful construction of fluorescently labeled magnetic antibody-like nanoparticles (ANPs) via a facile one-step surface-initiated in situ molecular imprinting approach over silica coated magnetite (Fe3O4@SiO2) core-shell nanocomposites. The as-prepared ANPs had a highly compact structure with an overall size of 83 ± 5 nm in diameter and showed excellent aqueous dispersion stability. With the predetermined high specificity to the target protein and high biocompatibility, the ANPs enabled rapid, efficient, selective and optically trackable sequestration of target proteins within living cells.

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By combination of a modified block PCR and endonuclease IV-based signal amplification system, we have developed a novel approach for ultra-sensitive detection of point mutations. The method can effectively identify mutant target sequence immersed in a large background of wild-type sequences with abundance down to 0.03% (for C→A) and 0.

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