In this work, a kind of novel Chitosan (Cs)-doped zeolite imidazole framework (ZIF-8@Cs) with a larger surface area and a smaller pore size was synthesised via a facial solvothermal approach and applied to remove Cu2+ from mine wastewater. Compared to nondoped ZIF-8, ZIF-8@Cs exhibited a stronger adsorption performance and removal efficiency. The reason was that ZIF-8@Cs doped by the Cs could suppress the aggregation and increase the monodispersity of ZIF-8. Using the high-performance ZIF-8@Cs, as a novel adsorbent, was successfully developed for the efficient removal of Cu2+ from mine wastewater. Various parameters, such as contact time, initial Cu2+ concentration, adsorbent dosage, and pH, were investigated. The results showed that a removal efficiency of 85% was obtained at 4 h contact time for a Cu2+ concentration of 30 mg/L at the optimum pH of 6.0. Equilibrium data were analysed using different isothermal models and kinetic models, analytic results indicated that the capture of Cu2+ by ZIF-8@Cs could favourably comply with the pseudo-first-order kinetic model and Langmuir isotherm model. The single-layer adsorption of Cu2+ on ZIF-8@Cs was dominated by diffusional mass transfer. Additionally, the results of the thermodynamic analysis indicated that the adsorption of Cu2+ by ZIF-8/Cs was a spontaneous, exothermic, and ordered process. Overall, the results reported herein indicated that ZIF-8/Cs with high adsorption efficiency are very attractive and imply a potential practical application for the removal of potentially toxic elements in wastewater.

In this investigation, a hydrogel adsorbent featuring remarkable efficiency in dye adsorption was successfully synthesized by the integration of natural polysaccharide (pullulan) and nanoparticles (ZIF-8@PDA). The prepared natural polysaccharide nanocomposite hydrogels not only exhibit superior mechanical strength and biocompatibility, but also demonstrate adeptness in the removal of dye pollutants. The dye removal capacities were 615.4 mg/g for malachite green (MG) and 525.8 mg/g for Congo red (CR), respectively. Notably, the adsorption process exhibits minimal susceptibility to variations in water quality and the presence of co-existing ions. The pH-responsive surface charge conversion capability of the adsorbent renders it recyclable, maintaining a dye adsorption performance exceeding 88 % even after 5 cycles of repeated usage. Overall, these environmentally friendly natural polysaccharide nanocomposite hydrogels hold potential for addressing complex wastewater treatment challenges and long-term use.

Triple-negative breast cancer (TNBC) is characterized by higher recurrence rate and mortality. Thermally-mediated ablation via photothermal therapy (PTT) demonstrates considerable promise for the eradication of breast cancer. Nonetheless, the efficacy of PTT is impeded by the thermal tolerance of tumor cells, which is attributed to the augmented expression of heat shock proteins (HSPs). These proteins, which function as ATP-dependent molecular chaperones, confer protection to cancer cells against the cytotoxic heat generated during PTT. Glycolysis is an important way for breast cancer cells to produce ATP, which can promote the occurrence and development of lung metastasis of breast cancer. Therefore, inhibiting glycolysis may diminish the expression of HSPs, curtail the growth of breast cancer, and prevent its metastasis. Glycolytic metabolism plays a pivotal role in the ATP biosynthesis within breast cancer cells, facilitating the progression and dissemination of pulmonary metastases. Consequently, targeting glycolysis presents a strategic approach to HSP expression, the proliferation of breast cancer, and impede its metastatic spread. Herein, we designed an indocyanine green (ICG) and cryptotanshinone (CTS) loaded hyaluronic acid (HA) coated Zeolitic Imidazolate Framework-8 (ZIF-8) drug delivery system. The drug delivery system had excellent photothermal properties, which could reach temperature sufficient for photothermal ablation of tumor cells. (ICG + CTS)@HA-ZIF-8 also showed pH-responsive drug release, enhancing the sustained release of ICG and CTS to extend their systemic circulation duration. Moreover, the HA modification of ZIF-8 served to augment its targeting capabilities both in vitro and in vivo, leveraging the enhanced permeation and retention (EPR) effect, as well as active tumor targeting via the CD44 receptor pathway, resulting in a higher drug concentration and a better therapeutic effect in tumor. (ICG + CTS)@HA-ZIF-8 could downregulate the expression of glycolysis-related protein pyruvate kinase-M2 (PKM2), thereby inhibiting the glycolysis process, further suppressing tumor cell energy metabolism, downregulating the expression of HSPs, overcoming tumor cell heat resistance, and improving PTT effect. It exhibited a notable suppressive impact on both the proliferation and migration of breast cancer cells, potentially offering innovative insights for the visualized PTT in breast cancer treatment.

Triethylamine (TEA) is a typical volatile organic compound (VOC) widely present in air and water, produced in industrial production activities, with high toxicity and great harm. Fluorescence detection and resistive sensing are effective methods for detecting pollutants. Here, In-doped interpenetrating twin ZIF-8 and its annealed derivatives have been successfully designed and prepared as a multifunctional TEA sensor. On the one hand, ZIF-8-In exhibits excellent fluorescence emission enhancement at 450 nm in a dose-dependent manner to TEA in water within the concentration range of 1-100 ppm, with a detection limit as low as 1 ppm. On the other hand, the annealed ZIF-8-In derivative is ZnO/In2O3 with a porous hierarchical structure, which is a perfect sensitive material for manufacturing gas sensors. Within the concentration range of 1-100 ppm, the ZnO/In2O3 gas sensor has a high response for 100 ppm TEA, reaching 107.7 (Ra/Rg), and can detect TEA gas as low as 1 ppm. Furthermore, the response of ZnO/In2O3 sensors to TEA is at least 10 times that of the other four VOC gases, demonstrating excellent gas selectivity. This multifunctional sensor can adapt to complex detection situations, demonstrating good application prospects.

The ability to sensitively and quantitatively detect uranyl in complex samples plays a vital role in environmental monitoring. In this work, an MOF-coated gold (Au) nanohybrid was synthesized for uranyl detection by surface-enhanced Raman scattering (SERS) technology. The MOF shell not only prevents the Au nanoparticles from rapid aggregation, but also effectively enhances the Raman signal of uranyl. A detection limit of as low as 0.5 μM could be achieved in solution, which could be comparable to the previously reported ones from SERS-based approaches. Moreover, the prepared SERS-active substrate was also applied to uranyl detection in real samples.

The unique design of the core-shell heterostructure is significant for obtaining electrode materials with excellent electrochemical properties. In this paper, porous carbon nanofibers (NPC@PPZ) embedded with N-doped porous carbon nanoparticles are used to construct flexible electrodes (NPC@PPZ@Bi2O3). Zeolite imidazole skeleton (ZIF)-8 and poly(methyl methacrylate) (PMMA) derived porous carbon fibers and Bi2O3 nanosheets, were utilized as the porous core and multilayer shell, respectively. The unique core and shell result in abundant pores and channels for fast ion transport and storage, high specific surface area, and additional electroactive sites. This perfect structural design enables the NPC@PPZ@Bi2O3 composite electrode to have excellent electrochemical performance. The results show that this electrode can obtain a high specific capacitance of 697 F g-1 at a current density of 1 A g-1 and a stable cycling performance at a high current density of 5 A g-1. The strategy developed in this study provides a new approach for the design and fabrication of flexible supercapacitors by electrostatic spinning combined with hierarchical porous structures.

Periodontitis is a chronic inflammatory disease caused by plaque that destroys the alveolar bone tissues, resulting in tooth loss. Poor eradication of pathogenic microorganisms, persistent malignant inflammation and impaired osteo-/angiogenesis are currently the primary challenges to control disease progression and rebuild damaged alveolar bone. However, existing treatments for periodontitis fail to comprehensively address these issues. Herein, an injectable composite hydrogel (SFD/CS/ZIF-8@QCT) encapsulating quercetin-modified zeolitic imidazolate framework-8 (ZIF-8@QCT) is developed. This hydrogel possesses thermo-sensitive and adhesive properties, which can provide excellent flowability and post-injection stability, resist oral fluid washout as well as achieve effective tissue adhesion. Inspirationally, it is observed that SFD/CS/ZIF-8@QCT exhibits a rapid localized hemostatic effect following implantation, and then by virtue of the sustained release of zinc ions and quercetin exerts excellent collective functions including antibacterial, immunomodulation, pro-osteo-/angiogenesis and pro-recruitment, ultimately facilitating excellent alveolar bone regeneration. Notably, our study also demonstrates that the inhibition of osteo-/angiogenesis of PDLSCs under the periodontitis is due to the strong inhibition of energy metabolism as well as the powerful activation of oxidative stress and autophagy, whereas the synergistic effects of quercetin and zinc ions released by SFD/CS/ZIF-8@QCT are effective in reversing these biological processes. Overall, our study presents innovative insights into the advancement of biomaterials to regenerate alveolar bone in periodontitis.

This work has applied metal-organic frameworks (MOFs) with high adsorbability and catalytic activity to develop electrochemical sensors to determine free chlorine (free-Cl) concentrations in aqueous media. A zeolitic imidazolate frameworks, Zn(Hmim)2 (ZIF-8) has been synthesized and incorporated with CuO nanosheets to decorate a glassy carbon electrode (GCE) and provide a new sensor for free-Cl determination. The as-prepared ZIF-8 and CuO-ZIF-8 composites have been characterized by FESEM, EDX, XRD, and FT-IR analyses. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) utilized to characterize the CuO-ZIF-8/GC modified electrode electrochemically, demonstrated the ability of the sensor to measure free-Cl concentration. Using differential pulse voltammetry (DPV) and under the optimal conditions, the prepared CuO-ZIF-8/GC modified electrode showed a linear response in the 0.25-60 ppm range with a 12 ppb detection limit (LOD) for free-Cl concentration. Finally, the fabricated sensor was applied to analyze free-Cl from actual swimming pool water samples with promising 97.5 to 103.0% recoveries.

The repair of large bone defects poses a significant challenge in orthopedics. Polyetheretherketone (PEEK) is a promising bone substitute, while it suffers a lack of bioactivity. Although several studies have been performed to further improve the bioactivities of PEEK by various surface modifications, PEEK offering long-term, multifaceted biofunctionalities remains still desired. In this study, we introduced metal-organic frameworks (MOFs), specifically ZIF-8 loaded with celecoxib (ZIF-8(CEL)), onto the PEEK surface through dopamine adhesion. The resulting PEEK@ZIF-8(CEL) aims to achieve long-term stable release of Zn ions and CEL for enhanced bone integration. Material characterization and biological experiments confirmed the successful integration of ZIF-8(CEL) onto PEEK and its positive biomedical effects, including creating a positive bone immunological environment and promoting bone growth. This study demonstrates the potential of PEEK@ZIF-8(CEL) as a novel repair material for large bone defects, offering a promising alternative in orthopedic applications.

An outstanding challenge for the field of metal-organic frameworks (MOFs) is structuring to form forms with greater useability. Reactive extrusion printing (REP) is a technique for the direct formation of films from their molecular components on-demand and on-location. Here we apply REP for the first time to zeolitic imidazolate frameworks (ZIFs) and study the interplay of solvent and molarity ratio on the phase distribution between ZIF-8 and ZIF-L in reactive printed films. Our results show that REP controllably directs phase formation between ZIF-L and ZIF-8 and that REP also gives control over crystal size and that high-quality ZIF-8 films, in particular, are produced in low-dispersity interconnected nanoparticulate form. Importantly, we show that REP is responsive to established surface-functionalization techniques to control important printing parameters of line width and thickness. This work expands the repertoire of REP to the important class of ZIFs.