Jinjuan Qiao,Xiangying Meng,Yufang Sun,Qian Li,Ronglan Zhao,Yun Zhang,Jiaqi Wang,Zhengjun Yi
Accurate and rapid identification of methicillin-resistant Staphylococcus aureus (MRSA) is of important clinical significance. In this study, a novel aptamer-based fluorometric assay was developed for detection of MRSA in clinical samples by coupling with immunomagnetic separation . The S. aureus cells in clinical specimens were enriched by magnetic separation. Following lysis by staphylococcal lysin , the PBP2a proteins were released from S. aureus cells and detected by the aptamer-based fluorometric assay. Without lengthy period of bacteria cultivation in the traditional susceptibility testing, this test has an overall testing time of only 2 h with the detection limit of 2.63 × 10 3 and 1.38 × 10 3 CFU/mL in PBS and spiked nasal swab, respectively. Since it is simple, rapid and sensitive, this method could be used for the detection of MRSA in various clinical samples.
Graphical In this paper, the nanocomposites with dodecahedral structure ZIF-8@ZIF-67 and BBH@ZIF-8@ZIF-67 have been synthesized by one-pot method. Bimetallic MOFs ZIF-8@ZIF-67 exhibited superior antibacterial properties and good biocompatibility. BBH-loaded ZIF-8@ZIF-67 showed enhanced synergistic antibacterial activity. Molecular docking suggests that PBP2a and DHFR may be potential antibacterial targets of BBH. Stimulus-responsive nanocarrier materials have garnered significant attention in biomedical science. Among them, metal-organic frameworks (MOFs) have emerged as promising candidates due to their remarkable antibacterial properties and pH sensitivity. In this study, a pH-responsive bimetallic MOFs carrier, ZIF-8@ZIF-67, was successfully synthesized for the delivery of berberine hydrochloride (BBH). Comprehensive characterization using UV-Vis spectroscopy, FT-IR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) confirmed the successful synthesis and structural integrity of ZIF-8@ZIF-67 and BBH@ZIF-8@ZIF-67. Subsequently, the drug release behavior, antibacterial efficacy, and biocompatibility of the composite material were systematically evaluated. Our findings revealed that BBH@ZIF-8@ZIF-67 exhibited well-controlled drug release properties, excellent antibacterial effects and biocompatibility. Furthermore, molecular docking results revealed that penicillin-binding protein 2a and dihydrofolate reductase in S. aureus may serve as two potential antibacterial targets for BBH. This research provides valuable insights into the use of bimetallic MOFs materials for developing highly efficient stimulus-responsive nanocarrier systems in biomedical applications.
The treatment of bacterial wound infection, particularly that caused by methicillin-resistant Staphylococcus aureus (MRSA), presents significant challenges owing to biofilm formation, multidrug resistance, and immune evasion. Here, we have rationally designed a multifunctional composite nanozyme (FTM) consisting of tannic acid (TA) and ferric ion (Fe 3+ ) coordination compound loaded with antibiotic drug methicillin (Meth), which is capable of realizing pH-responsive self-adaptive regulation of oxidative stress for enhancing the treatment of MRSA-infected wound. During the early stages of wound infection (pH < 6.5), FTM demonstrates significant peroxidase-like activity for effectively catalyzing the conversion of endogenous H 2 O 2 into highly toxic hydroxyl radical (•OH), which not only directly damages MRSA and eliminates its biofilm for chemodynamic therapy (CDT), but also disrupts the penicillin-binding protein 2a (PBP2a) to restore the sensitivity of MRSA to methicillin. Meanwhile, FTM exhibits strong near-infrared (NIR) absorption, achieving photothermal antibacterial therapy (PTT). While in the later stages (after complete elimination of MRSA), as the infectious microenvironment of wound becomes neutral (pH 7.4), FTM mainly reveals the superoxide dismutase (SOD)-like activity for scavenging excess reactive oxygen species (ROS), ultimately reducing oxidative stress and promoting tissue repair. In vitro and in vivo experiments show that the proposed FTM nanozyme with triple bactericidal modalities achieves satisfactory antibacterial and antibiofilm therapy and accelerates wound healing process. Consequently, by adapting to the dynamic changes of wound microenvironment, this multifunctional nanoplatform offers a promising strategy for treating drug-resistant wound infections.
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