The Progress and Prospect of Zeolitic Imidazolate Frameworks in Cancer Therapy, Antibacterial Activity, and Biomineralization

Recent advances and synergistic effect of bioactive zeolite imidazolate frameworks (ZIFs) for biosensing applications

The rapid developments in the field of zeolitic imidazolate frameworks (ZIFs) in recent years have created unparalleled opportunities for the development of unique bioactive ZIFs for a range of biosensor applications. Integrating bioactive molecules such as DNA, aptamers, and antibodies into ZIFs to create bioactive ZIF composites has attracted great interest. Bioactive ZIF composites have been developed that combine the multiple functions of bioactive molecules with the superior chemical and physical properties of ZIFs. This review thoroughly summarizes the ZIFs as well as the novel strategies for incorporating bioactive molecules into ZIFs. They are used in many different applications, especially in biosensors. Finally, biosensor applications of bioactive ZIFs were investigated in optical (fluorescence and colorimetric) and electrochemical (amperometric, conductometric, and impedance) fields. The surface of ZIFs makes it easier to immobilize bioactive molecules like DNA, enzymes, or antibodies, which in turn enables the construction of cutting-edge, futuristic biosensors.

Carbon-dots encapsulated luminescent metal-organic frameworks@surface molecularly imprinted polymer: A facile fluorescent probe for the determination of chloramphenicol

In this study, carbon dots (CDs)-encapsulated luminescent metal-organic frameworks@surface molecularly imprinted polymer (CDs@MOF@SMIP) was facilely prepared and applied as fluorescent probe for specific identification and sensitive detection of chloramphenicol (CAP) in food. Fluorescent CDs, serving as signal tags, were encapsulated within metal-organic backbones (ZIF-8), yielding luminescent MOF materials (CDs@ZIF-8). The synthesized CDs, CDs@ZIF-8 and CDs@ZIF-8@SMIP were investigated by morphological and structural characterizations (UV-Vis, XRD, FT-IR, BET, TEM). The CDs@ZIF-8@SMIP probe was demonstrated to have remarkable selectivity and sensitivity towards CAP. Its fluorescence decreased linearly with CAP concentration from 0.323 μg L-1 (0.001 μM) to 8075.0 μg L-1 (25.0 μM), featuring a low detection limit of 0.08 μg L-1. The CDs@ZIF-8@SMIP-based fluorescence strategy achieved satisfactory recoveries (95.5 % - 101.0 %) in CAP-spiked commercial foods with RSD < 4.4 % (n = 3). These results indicate that this method can effectively detect trace CAP in food matrices and has broad application prospects.

In vitro cytotoxicity of magnetic-fluorescent bioactive glasses on SaOS-2, MC3T3-E1, BJ fibroblast cells, their hemolytic activity, and sorafenib release behavior

In the study, the fabrication of superparamagnetic-fluorescent bioactive glasses in the form of the particle, nanofiber, and 3D scaffolds was performed by including maghemite (γ-Fe2O3) nanoparticles and photoluminescent rare earth element ions (Eu3+, Gd3+, and Yb3+) using sol-gel, electrospinning, and robocasting techniques, respectively. The in vitro cytotoxicity of the magnetic-fluorescent bioactive glasses on osteosarcoma SaOS-2, pre-osteoblast MC3T3-E1, and BJ fibroblast cells, as well as their hemolytic activity and sorafenib tosylate loading and release behavior, were investigated. The cytotoxicity of the bioactive glass samples was tested using the MTT assay. Additionally, the alkaline phosphatase activity of the studied glasses was examined as a function of time. The mineralization behavior of the pre-osteoblast cell-seeded glass samples was analyzed using Alizarin red S staining. Results revealed that the in vitro cytotoxicity of the studied bioactive glasses in the form of particles and nanofibers depended on the sample concentration, whereas in the case of the 3D scaffolds, no cytotoxic response was observed on the osteosarcoma, pre-osteoblast, and fibroblast cells. Similarly, particle and nanofiber-based glass samples induced dose-dependent hemolysis on red blood cells. Drug loading rates were much lower for the 3D scaffolds compared to the particle and nanofiber-based samples. Drug release rates ranged from 25 % to 90 %, depending on the bioactive glass morphology and the pH of the release medium. It was concluded that the studied bioactive glasses have the potential to be used in tissue engineering applications and cancer therapy.

Spatiotemporally controlled AuNPs@ZIF-8 based nanocarriers for synergistic photothermal/chemodynamic therapy

High efficiency and spatio-temporal control remains a challenge for multi-modal synergistic cancer therapy. Herein, based on gold nanoparticles (AuNPs) and zeolite-like imidazole skeleton material (ZIF-8), a spatio-temporal controllable photothermal/ chemical dynamic/ chemotherapy three modal synergistic anti-tumor nano-carrier (HAZD) was developed. HAZD has a size of 128.75 ± 11.86 nm, a drug loading ratio of 21.5 ± 2.2 % and an encapsulation efficiency of 71.8 ± 1.7 %. Stability, acid responsive release character, outstanding catalytic ability to generate ROS, relatively high thermal conversion efficiency up to 62.38 % and spatio-temporal controllable abilities are also found within this nano-carrier. Furthermore, HAZD performed good antitumor ability in vivo with the comprehensive effects of photothermal/ chemical dynamic/ chemotherapy. The tumor growth inhibition value is 97.1 % within 12 days, indicating its great potential in multi-modal synergistic cancer therapy. STATEMENT OF SIGNIFICANCE: Cancer remains one of the major culprits that seriously harm human health currently. With the development of materials and nanotechnology, great improvements have been made in multimodal anti-tumor strategies. However, temporal- and spatial-controllable multi-modal synergistic nanocarriers are urgently awaited for efficient and low-toxicity tumor therapy. This article proposes a spatio-temporally controllable three-modal anti-tumor strategy and designs an anti-tumor drug delivery system based on gold nanoparticles (AuNPs) and zeolite-like imidazole skeleton material (ZIF-8), which shows acid-responsive release characteristics, catalytic ability to generate ROS, relatively high thermal conversion efficiency up to 62.38 %, as well as spatio-temporal controllable abilities. Moreover, it demonstrates outstanding anti-tumor ability, with a tumor growth inhibition value of 97.1 % within 12 days, revealing its significant potential for future personalized and precise anti-tumor treatments.

Establishment of bone-targeted nano-platform and the study of its combination with 2-deoxy-d-glucose enhanced photodynamic therapy to inhibit bone metastasis

At present, simple anti-tumor drugs are ineffective at targeting bone tissue and are not purposed to treat patients with bone metastasis. In this study, zoledronic acid (ZOL) demonstrated excellent bone-targeting properties as a bone-targeting ligand. The metal-organic framework (MOF) known as ZIF-90 was modified with ZOL to construct a bone-targeting-based drug delivery system. Chlorin e6 (Ce6) was loaded in the bone-targeted drug delivery system and combined with 2-deoxy-D-glucose (2-DG), which successfully treated bone tumors when enhanced photodynamic therapy was applied. The Ce6@ZIF-PEG-ZOL (Ce6@ZPZ) nanoparticles were observed to have uniform morphology, a particle size of approximately 210 nm, and a potential of approximately -30.4 mV. The results of the bone-targeting experiments showed that Ce6@ZPZ exhibited a superior bone-targeted effect when compared to Ce6@ZIF-90-PEG. The Ce6@ZPZ solution was subjected to 660 nm irradiation and the resulting production of reactive oxygen species increased over time, which could be further increased when Ce6@ZPZ was used in combination with 2-DG. Their combination had a stronger inhibitory capacity against tumor cells than either 2-DG or Ce6@ZPZ alone, increasing the rate of tumor cell apoptosis. The apoptosis rate caused by HGC-27 was 61.56% when 2-DG was combined with Ce6@ZPZ. In vivo results also showed that Ce6@ZPZ combined with 2-DG maximally inhibited tumor growth and prolonged mice survival compared to the other experimental groups. Therefore, the combination of PDT and glycolytic inhibitors serves as a potential option for the treatment of cancer.

Mechanism analysis of surface structure-regulated Cu2O in photocatalytic antibacterial process

The effects of exposing crystal planes and vacancy defect engineering can induce unique surface atom arrangements that strongly influence the physicochemical properties of semiconductor materials. This paper used Cu2O with different surface structures as a research model. A liquid-phase method was chosen for surface structure regulation to prepare Cu2O semiconductors (Vo-(111)Cu2O, Vo-(100)Cu2O, Vo-(110)Cu2O) with different exposed crystalline surfaces analyze the antibacterial mechanisms of other faceted models in the photodynamic antibacterial process. The bactericidal effect of Vo-(111)Cu2O (40 μg/mL, 100%) was better than that of Vo-(100)Cu2O and Vo-(110)Cu2O. DFT simulations show that the photocatalytic antimicrobial performance of Vo-(111)Cu2O is improved due to surface defect structures caused by unsaturated coordination bonds and suspension bonds on its exposed crystalline surfaces. The suspension bonds act as active centres for trapping electrons, leading to a lower carrier complexation rate on the material surface. The antibacterial mechanism of Vo-(111)Cu2O showed that oxidative sterilization by reactive oxygen species (ROS) was the dominant factor (61.98%) in the antibacterial process. The most potent depolarizing effect on E. coli, the highest copper ion solubilization, and the highest ROS yield. Therefore, ROS oxidative sterilization, copper ion leaching sterilization, and contact damage synergistically affect E. coli from the inside out.

Tailored Drug Delivery Platforms: Stimulus-Responsive Core-Shell Structured Nanocarriers

Core-shell structured nanocarriers have come into the scientific spotlight in recent years due to their intriguing properties and wide applications in materials chemistry, biology, and biomedicine. Tailored core-shell structures to achieve desired performance have emerged as a research frontier in the development of smart drug delivery system. However, systematic reviews on the design and loading/release mechanisms of stimulus-responsive core-shell structured nanocarriers are uncommon. This review starts with the categories of core-shell structured nanocarriers with different means of drug payload, and then highlights the controlled release mechanism realized through stimulus-response processes triggered under different environments. Finally, some multifaceted perspectives on the design of core-shell structured materials as drug carriers are addressed. This work aims to provide new enlightenments and prospects in the drug delivery field for further developing advanced and smart nanocarriers.

Smart packaging films based on corn starch/polyvinyl alcohol containing nano SIM-1 for monitoring food freshness

There is at present an acute need for the construction of biopolymer-based smart packaging material that can be applied for the real-time visual monitoring of food freshness. Herein, a nano-sized substituted imidazolate material (SIM-1) with ammonia-sensitive and antibacterial ability was effectively manufactured and then anchored within corn starch/polyvinyl alcohol (CS/PVA) blend to construct biopolymeric smart active packaging material. The structure, physical and functional performances of CS/PVA-based films with different content of SIM-1 (0.5, 1.0 and 2.0 wt% on CS/PVA basis) were then explored in detail. Results revealed that the incorporated SIM-1 nanocrystals were equally anchored within the CS/PVA matrix owing to the establishment of potent hydrogen-bonding interactions, which produced an obvious improvement in the compatibility of CS/PVA blend film, as well as its mechanical strength, water/oxygen barrier and UV-screening performances. The constructed CS/PVA/SIM-1 blend films further demonstrated superior long-term color stability property, ammonia-sensitive and antibacterial functions. Furthermore, the CS/PVA/SIM-1 blend films were utilized for effectively monitoring the deterioration of shrimp via observable color alteration. The above findings suggested the potential applications of CS/PVA/SIM-1 blend films in smart active packaging.

Nanozymes With Osteochondral Regenerative Effects: An Overview of Mechanisms and Recent Applications

With the discovery of the intrinsic enzyme-like activity of metal oxides, nanozymes garner significant attention due to their superior characteristics, such as low cost, high stability, multi-enzyme activity, and facile preparation. Notably, in the field of biomedicine, nanozymes primarily focus on disease detection, antibacterial properties, antitumor effects, and treatment of inflammatory conditions. However, the potential for application in regenerative medicine, which primarily addresses wound healing, nerve defect repair, bone regeneration, and cardiovascular disease treatment, is garnering interest as well. This review introduces nanozymes as an innovative strategy within the realm of bone regenerative medicine. The primary focus of this approach lies in the facilitation of osteochondral regeneration through the modulation of the pathological microenvironment. The catalytic mechanisms of four types of representative nanozymes are first discussed. The pathological microenvironment inhibiting osteochondral regeneration, followed by summarizing the therapy mechanism of nanozymes to osteochondral regeneration barriers is introduced. Further, the therapeutic potential of nanozymes for bone diseases is included. To improve the therapeutic efficiency of nanozymes and facilitate their clinical translation, future potential applications in osteochondral diseases are also discussed and some significant challenges addressed.

Recent advances and prospects of metal-organic frameworks in cancer therapies

Metal-organic frameworks (MOFs) have been broadly applied in biomedical and other fields. MOFs have high porosity, a large comparative area, and good biostability and have attracted significant attention, especially in cancer therapies. This paper presents the latest applications of MOFs in chemodynamic therapy (CDT), sonodynamic therapy (SDT), photodynamic therapy (PDT), photothermal therapy (PTT), immunotherapy (IT), and combination therapy for breast cancer. A combination therapy is the combination of two different treatment modalities, such as CDT and PDT combination therapy, and is considered more effective than separate therapies. Herein, we have also discussed the advantages and disadvantages of combination therapy in the treatment of breast cancer. This paper aims to illustrate the potential of MOFs in new cancer therapeutic approaches, discuss their potential advantages, and provide some reflections on the latest research results.

Current status and prospect of ZIF-based materials for breast cancer treatment

Breast cancer, one of the three most life-threatening cancers in modern times, must be explored for treatments with low side effects and practical efficacy. Metal organic framework materials (MOFs) is made by metal ions as the center for point and organic ligands as a bridge connecting a new type of porous nano-materials, among them, the zinc base zeolite imidazole skeleton material series (ZIFs) because of its excellent biocompatibility and pH slow controlled release ability, is widely used in the tumor microenvironment in basic research and achieved remarkable curative effect. Inspired by this, in this review, we focus on the recent research progress on the application of ZIFs in the treatment of breast cancer, mainly studying the structure of ZIFs such as ZIF-8, ZIF-90 and ZIF-67 and their application in novel therapies for breast cancer treatment, such as targeted drug delivery, photothermal therapy, immunotherapy and gene therapy.We will more fully demonstrate the potential of zif in breast cancer treatment, hoping to provide an avenue for exploring breast cancer treatment.

Core-shell inorganic NP@MOF nanostructures for targeted drug delivery and multimodal imaging-guided combination tumor treatment

It is well known that metal-organic framework (MOF) nanostructures have unique characteristics such as high porosity, large surface areas and adjustable functionalities, so they are ideal candidates for developing drug delivery systems (DDSs) as well as theranostic platforms in cancer treatment. Despite the large number of MOF nanostructures that have been discovered, conventional MOF-derived nanosystems only have a single biofunctional MOF source with poor colloidal stability. Accordingly, developing core-shell MOF nanostructures with good colloidal stability is a useful method for generating efficient drug delivery, multimodal imaging and synergistic therapeutic systems. The preparation of core-shell MOF nanostructures has been done with a variety of materials, but inorganic nanoparticles (NPs) are highly effective for drug delivery and imaging-guided tumor treatment. Herein, we aimed to overview the synthesis of core-shell inorganic NP@MOF nanostructures followed by the application of core-shell MOFs derived from magnetic, quantum dots (QDs), gold (Au), and gadolinium (Gd) NPs in drug delivery and imaging-guided tumor treatment. Afterward, we surveyed different factors affecting prolonged drug delivery and cancer therapy, cellular uptake, biocompatibility, biodegradability, and enhanced permeation and retention (EPR) effect of core-shell MOFs. Last but not least, we discussed the challenges and the prospects of the field. We envision this article may hold great promise in providing valuable insights regarding the application of hybrid nanostructures as promising and potential candidates for multimodal imaging-guided combination cancer therapy.

Advancing Nanoscale Science: Synthesis and Bioprinting of Zeolitic Imidazole Framework-8 for Enhanced Anti-Infectious Therapeutic Efficacies

Bacterial infectious disorders are becoming a major health problem for public health. The zeolitic imidazole framework-8 with a novel Cordia myxa extract-based (CME@ZIF-8) nanocomposite showed variable functionality, high porosity, and bacteria-killing activity against Staphylococcus aureus, and Escherichia coli strains have been created by using a straightforward approach. The sizes of synthesized zeolitic imidazole framework-8 (ZIF-8) and CME@ZIF-8 were 11.38 nm and 12.44 nm, respectively. Prepared metal organic frameworks have been characterized by gas chromatography-mass spectroscopy, Fourier transform spectroscopy, UV-visible spectroscopy, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. An antibacterial potential comparison between CME@ZIF-8 and zeolitic imidazole framework-8 has shown that CME@ZIF-8 was 31.3%, 28.57%, 46%, and 47% more efficient than ZIF-8 against Staphylococcus aureus and 43.7%, 42.8%, 35.7%, and 70% more efficient against Escherichia coli, while it was 31.25%, 33.3%, 46%, and 46% more efficient than the commercially available ciprofloxacin drug against Staphylococcus aureus and 43.7%, 42.8%, 35.7%, and 70% more efficient against Escherichia coli, respectively, for 750, 500, 250, and 125 μg mL-1. Minimum inhibitory concentration values of CME@ZIF-8 for Escherichia coli and Staphylococcus aureus were 15.6 and 31.25 μg/mL respectively, while the value of zeolitic imidazole framework-8 alone was 62.5 μg/mL for both Escherichia coli and Staphylococcus aureus. The reactive oxygen species generated by CME@ZIF-8 destroys the bacterial cell and its organelles. Consequently, the CME@ZIF-8 nanocomposites have endless potential applications for treating infectious diseases.

Self-Aggregated Nanoscale Metal-Organic Framework for Targeted Pulmonary Decorporation of Uranium

The limited availability of effective agents for removing actinides from the lungs significantly restricts the effectiveness of medical treatments for nuclear emergencies. Inhalation is the primary route of internal contamination in 44.3% of actinide-related accidents, leading to the accumulation of radionuclides in the lungs and resulting in infections and potential tumor formation (tumorigenesis). This study focuses on the synthesis of a nanometal-organic framework (nMOF) material called ZIF-71-COOH, which is achieved by post-synthetic carboxyl functionalization of ZIF-71. The material demonstrates high and selective adsorption of uranyl, while also exhibiting increased particle size (≈2100 nm) when it aggregates in the blood, enabling passive targeting of the lungs through mechanical filtration. This unique property facilitates the rapid enrichment and selective recognition of uranyl, making nano ZIF-71-COOH highly effective in removing uranyl from the lungs. The findings of this study highlight the potential of self-aggregated nMOFs as a promising drug delivery system for targeted uranium decorporation in the lungs.

Antibacterial and antibiofilm activities of ZIF-67

Currently, antibiotic-resistant bacteria represent a serious threat to public health worldwide. Biofilm formation potentiates both virulence and antibiotic resistance of bacteria. Therefore, the discovery of new antibacterial and antibiofilm compounds is an issue of paramount importance to combat and prevent hard-to-treat bacterial infections. Zeolitic-imidazolate-frameworks (ZIFs) are metallo-organic compounds known to have various interesting chemical and biological applications, including antibacterial properties. In this study, we synthesized ZIF-67 nanoparticles, formed by imidazolate anions and cobalt cations, and found that they inhibit the growth of Acinetobacter baumannii, Pseudomonas aeruginosa, and Staphylococcus aureus. Sub-inhibitory concentrations of ZIF-67 were also able to significantly reduce the biomass of pre-established biofilms of these pathogenic bacteria. On the other hand, the ZIF-67 nanoparticles had null or low cytotoxicity in mammalian cells at those concentrations showing antibacterial or antibiofilm activities. Thus, our results reveal the potential of ZIF-67 nanoparticles to be used against pathogenic bacteria.

Highly Water-Stable Zinc Based Metal-Organic Framework: Antibacterial, Photocatalytic Degradation and Photoelectric Responses

A reported water-stable Zn-MOF ([Zn(L)2(bpa)(H2O)2]·2H2O, H2L = 5-(2-cyanophenoxy) isophthalic acid has been prepared via a low-cost, general and efficient hydrothermal method. It is worth noting the structural features of Zn-MOF which exhibit the unsaturated metal site and the main non-covalent interactions including O⋯H, N⋯H and π-π stacking interactions, which lead to strong antibacterial and good tetracycline degradation ability. The average diameter of the Zn-MOF inhibition zone against Escherichia coli and Staphylococcus aureus was 12.22 mm and 10.10 mm, respectively. Further, the water-stable Zn-MOF can be employed as the effective photocatalyst for the photodegradation of tetracycline, achieving results of 67% within 50 min, and it has good cyclic stability. In addition, the photodegradation mechanism was studied using UV-vis diffuse reflection spectroscopy (UV-VIS DRS) and valence-band X-ray photoelectron spectroscopy (VB-XPS) combined with the ESR profile of Zn-MOF, which suggest that ·O2- is the main active species responsible for tetracycline photodegradation. Also, the photoelectric measurement results show that Zn-MOF has a good photocurrent generation performance under light. This provides us with a new perspective to investigate Zn-MOF materials as a suitable multifunctional platform for future environmental improvement applications.

Powering mesoporous silica nanoparticles into bioactive nanoplatforms for antibacterial therapies: strategies and challenges

Bacterial infection has been a major threat to worldwide human health, in particular with the ever-increasing level of antimicrobial resistance. Given the complex microenvironment of bacterial infections, conventional use of antibiotics typically renders a low efficacy in infection control, thus calling for novel strategies for effective antibacterial therapies. As an excellent candidate for antibiotics delivery, mesoporous silica nanoparticles (MSNs) demonstrate unique physicochemical advantages in antibacterial therapies. Beyond the delivery capability, extensive efforts have been devoted in engineering MSNs to be bioactive to further synergize the therapeutic effect in infection control. In this review, we critically reviewed the essential properties of MSNs that benefit their antibacterial application, followed by a themed summary of strategies in manipulating MSNs into bioactive nanoplatforms for enhanced antibacterial therapies. The chemically functionalized platform, photo-synergized platform, physical antibacterial platform and targeting-directed platform are introduced in details, where the clinical translation challenges of these MSNs-based antibacterial nanoplatforms are briefly discussed afterwards. This review provides critical information of the emerging trend in turning bioinert MSNs into bioactive antibacterial agents, paving the way to inspire and translate novel MSNs-based nanotherapies in combating bacterial infection diseases.

Enhanced Osteogenic Activity and Bone Repair Ability of PLGA/MBG Scaffolds Doped with ZIF-8 Nanoparticles Loaded with BMP-2

Background

Tissue engineering scaffolds are porous and can be loaded with growth factors to promote osteogenesis and bone repair, which can solve the problem of clinical bone defects. The direct loading of growth factors on scaffolds is hindered by the disadvantages of low loading capacities, and uncontrollable burst release. Zeolitic imidazolate framework-8 (ZIF-8) has osteoinductive activity and drug-loading potential and can be loaded with growth factors to achieve sustained release. In this study, we aimed to establish a sustained release system of composite scaffolds loaded with growth factors to achieve the goal of slow controlled release and effective bone repair.

Methods

ZIF‑8 nanoparticles loaded with bone morphogenetic protein-2 (BMP-2) were incorporated into poly-(lactide-co-glycolide)/mesoporous bioactive glass (PLGA/MBG) porous scaffolds by a 3D-printing method. The surface morphology, chemical properties and BMP-2 release of the prepared scaffold were investigated. The osteoblast adhesion, proliferation, spreading, and osteogenic differentiation in vitro and the bone repair ability in vivo of the PLGA/MBG/ZIF-8/BMP-2 (PMZB) scaffold were evaluated, and compared with those of PLGA/MBG (PM) and PLGA/MBG/ZIF-8 (PMZ) scaffolds.

Results

The results showed that the PMZB scaffold exhibited a slow and continuous BMP-2 release pattern, enhanced osteoblast adhesion, proliferation, spreading and osteogenic differentiation in vitro, and promoted new bone formation and bone repair in vivo.

Conclusion

The PLGA/MBG/ZIF-8/BMP-2 porous scaffold could continuously and slowly release BMP-2, enhance osteogenic activity, and promote new bone formation and bone repair at bone defects. The PMZB scaffold can be used as a bone graft material to repair bone defect at non-weight-bearing sites.

GSH-Activatable Metal-Phenolic Networks for Photothermal-Enhanced Chemotherapy and Chemodynamic Therapy

Chemotherapy (CT) plays an important role in the antitumor process, but the unsatisfactory therapeutic efficacy and the obvious toxic side effects of CT seriously restrict its application. To overcome the limitations of CT, the strategy of chemotherapy enhanced by chemodynamic therapy (CDT) and photothermal therapy (PTT) has been considered a promising approach to improve the anticancer effect. Herein, a novel GSH-activatable Cu2+-Quercetin network (QC) was synthesized via a convenient strategy to load Au nanoparticles (NPs) and DOX, named QCDA, for the synergistic therapy of CT/CDT/PTT. The results showed that QCDA exhibited GSH-sensitive degradation and "cargos" release in cancer cells, and then PTT and CDT caused by Au NPs and Cu+ significantly enhanced the CT effect of DOX and Quercetin on anticancer. More importantly, the PTT and depleted GSH accelerated the Fenton-like ionization process resulting in facilitating the CDT efficiency. Collectively, the multi-mode synergistic strategy of CT/CDT/PTT, which showed an excellent therapeutic effect, maybe a potential therapeutic pathway for anticancer.

Tetrahedral Imidazolate Frameworks with Auxiliary Ligands (TIF-Ax): Synthetic Strategies and Applications

Zeolitic imidazolate frameworks (ZIFs) are an important subclass of metal-organic frameworks (MOFs). Recently, we reported a new kind of MOF, namely tetrahedral imidazolate frameworks with auxiliary ligands (TIF-Ax), by adding linear ligands (Hint) into the zinc-imidazolate system. Introducing linear ligands into the M2+-imidazolate system overcomes the limitation of imidazole derivatives. Thanks to the synergistic effect of two different types of ligands, a series of new TIF-Ax with interesting topologies and a special pore environment has been reported, and they have attracted extensive attention in gas adsorption, separation, catalysis, heavy metal ion capture, and so on. In this review, we give a comprehensive overview of TIF-Ax, including their synthesis methods, structural diversity, and multi-field applications. Finally, we also discuss the challenges and perspectives of the rational design and syntheses of new TIF-Ax from the aspects of their composition, solvent, and template. This review provides deep insight into TIF-Ax and a reference for scholars with backgrounds of porous materials, gas separation, and catalysis.

Targeting telomerase utilizing zeolitic imidazole frameworks as non-viral gene delivery agents across different cancer cell types

Telomerase, a ribonucleoprotein coded by the hTERT gene, plays an important role in cellular immortalization and carcinogenesis. hTERT is a suitable target for cancer therapeutics as its activity is highly upregulated in most of cancer cells but absent in normal somatic cells. Here, by employing the two Metal-Organic Frameworks (MOFs), viz. ZIF-C and ZIF-8, based biomineralization we encapsulate Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR)/Cas9 plasmid system that targets hTERT gene (CrhTERT) in cancer cells. When comparing the two biocomposites, ZIF-C shows the better loading capacity and cell viability. The loaded plasmid in ZIF-C is highly protected against enzymatic degradation. CrhTERT@ZIF-C is efficiently endocytosed by cancer cells and the subcellular release of CrhTERT leads to telomerase knockdown. The resultant inhibition of hTERT expression decreases cellular proliferation and causing cancer cell death. Furthermore, hTERT knockdown shows a significant reduction in tumour metastasis and alters protein expression. Collectively we show the high potential of ZIF-C-based biocomposites as a promising general tool for gene therapy of different types of cancers.

Development of a ZIF-91-Porous-Liquid-Based Composite Hydrogel Dressing System for Diabetic Wound Healing

Porous metal-organic framework (MOF) liquids with permanent porosity, good fluidity, and fine dispersion attract broad attention in catalysis, transportation, gas storage, and chemical separations. Yet, the design and synthesis of porous MOF liquids for drug delivery remain less explored. Herein, a simple and general strategy is reported to prepare ZIF-91 porous liquid (ZIF-91-PL) via surface modification and ion exchange. The cationic nature of ZIF-91-PL not only renders it antibacterial but also with high curcumin loading capacity and sustained release. More importantly, the acrylate group on the grafted side chain of ZIF-91-PL makes it feasible to crosslink with modified gelatin through light curing, and the obtained hydrogel shows a significantly improved healing effect on the wound of diabetes. This work demonstrates for the first time, a MOF-based porous liquid for drug delivery, and the further fabrication of composite hydrogel may have potential applications in biomedical science.

Navigating zinc-involved nanomedicine in oncotherapy

Zinc (Zn), extolled as "the flower of life" in modern medicine, has been extensively highlighted with its physiological functions to maintain growth, development, and metabolism homeostasis. Driven by the substantial advancement of nanotechnology and oncology, Zn-involved nanomedicines integrating the intrinsic bioactivity of Zn species and the physiochemical attributes of Zn-composed nanosystems have blazed a highly efficient and relatively biosafe antineoplastic path. In this review, we aim to highlight and discuss the recent representative modalities of emerging Zn-involved oncology nanomedicine, mainly emphasizing the rational design, biological effect and biosafety, and therapeutic strategies. In addition, we provide the underlying critical obstacles and future perspectives of Zn-involved oncology nanomedicines, primarily focusing on the chances and challenges of clinical translation. Furthermore, we hope the review can give rise to opportunities within oncology nanomedicine and other biomedical fields, promoting the prosperity and progress of the "Zincic Age".

Intracellular Delivery of Itaconate by Metal–Organic Framework-Anchored Hydrogel Microspheres for Osteoarthritis Therapy

Treatment of osteoarthritis (OA) remains a significant clinical challenge. Itaconate (IA), an emerging regulator of intracellular inflammation and oxidative stress, may potentially be harnessed to treat OA. However, the short joint residence time, inefficient drug delivery, and cell-impermeable property of IA can seriously hamper the clinical translation. Herein, IA-encapsulated zeolitic imidazolate framework-8 (IA-ZIF-8) nanoparticles were self-assembled by zinc ions, 2-methylimidazole, and IA to render them pH-responsive. Subsequently, IA-ZIF-8 nanoparticles were firmly immobilized in hydrogel microspheres via one-step microfluidic technology. It was demonstrated in vitro experiments that IA-ZIF-8-loaded hydrogel microspheres (IA-ZIF-8@HMs) exhibited good anti-inflammatory and anti-oxidative stress effects by releasing pH-responsive nanoparticles into chondrocytes. Importantly, compared with IA-ZIF-8, IA-ZIF-8@HMs showed better performance in the treatment of OA due to their superior performance in sustained release. Thus, such hydrogel microspheres not only hold enormous potential for OA therapy, but also provide a novel avenue for cell-impermeable drugs by constructing appropriate drug delivery systems.

Zeolitic Imidazole Framework-90-Based Pesticide Smart-Delivery System with Enhanced Antimicrobial Performance

Multimodal antimicrobial technology is regarded as a promising strategy for controlling plant diseases because it enhances antimicrobial efficacy by blocking multiple pesticide-resistance pathways. In this work, a pH-responsive multimodal antimicrobial system was constructed based on ZIF-90 for the controlled release of kasugamycin (KSM). A series of physicochemical characterizations confirmed the successful fabrication of ZIF-90-KSM. The results indicated that the loading capacity of ZIF-90-KSM for KSM was approximately 6.7% and that the ZIF-90 nanocarriers could protect KSM against photodegradation effectively. The acid pH at the site of disease not only decompose the Schiff base bonds between KSM and ZIF-90, but also completely dissolved the nanocarriers. The simultaneous release of KSM and Zn²⁺ ions was able to achieve multimodal antimicrobial functions during disease occurs. A bioactivity survey indicated that ZIF-90-KSM had superior fungicidal activity and longer duration against Magnaporthe oryzae than KSM aqueous solution. In addition, the phytotoxicity assessment of ZIF-90-KSM on rice plants did not reveal any adverse effects. Therefore, ZIF-90-KSM prepared by Schiff base reaction has great potential for achieving synergistic antifungal functions and provides an eco-friendly approach to manage rice diseases.

Acid-Responsive Multifunctional Zeolitic Imidazolate Framework-8 (ZIF-8) Nanocomposites for Tumor Chemo-Photothermal Synergistic Therapy

Camptothecin (CPT), a broad-spectrum anticancer drug, has been extensively used clinically. However, its hydrophobic properties seriously hinder its antitumor therapeutic effect. Herein, we synthesized acid-degradable Fe₃O₄@poly(vinylpyrrolidone) (Fe₃O₄@PVP)/gold nanoclusters@zeolitic imidazolate framework-8 composite nanoparticles (ZIF-8CNPs) via a facile method and utilized them as carriers to efficiently load CPT. The excellent fluorescence properties of gold nanoclusters (AuNCs) and the photothermal properties of Fe₃O₄@poly(vinylpyrrolidone) (Fe₃O₄@PVP) endowed the nanocomposites with excellent cell imaging and photothermal functions. In addition, the surface modification of the composite nanoparticles with folic acid-grafted bovine serum albumin (FA-BSA) enables them to efficiently target tumor cells. Once FA-BSA/ZIF-8CNPs-CPT are taken up by tumor cells and irradiated with a near-infrared laser, the nanoparticles show a highly effective inhibitory effect against various tumor cells through a chemo-photothermal synergistic effect. Hence, it is conceivable that this acid-responsive multifunctional ZIF-8 nanocomposite has promising bioapplication prospects in cancer treatment.

A mass-tagged MOF nanoprobe approach for ultra-sensitive protein quantification in tumor-educated platelets

A mass-tagged metal-organic framework (MOF) nanoprobe approach was developed for ultra-sensitive quantification of platelet protein CD44 by integrating activable aptamer recognition and MOF nanoprobe signal amplification with mass spectrometric detection. This approach offered high sensitivity and quantitative capability for low abundant protein analysis in tumor-educated platelets (TEPs), exhibiting great potential in cancer diagnosis and management.

Carrier strategies boost the application of CRISPR/Cas system in gene therapy

Emerging clustered regularly interspaced short palindromic repeat/associated protein (CRISPR/Cas) genome editing technology shows great potential in gene therapy. However, proteins and nucleic acids suffer from enzymatic degradation in the physiological environment and low permeability into cells. Exploiting carriers to protect the CRISPR system from degradation, enhance its targeting of specific tissues and cells, and reduce its immunogenicity is essential to stimulate its clinical applications. Here, the authors review the state-of-the-art CRISPR delivery systems and their applications, and describe strategies to improve the safety and efficacy of CRISPR mediated genome editing, categorized by three types of cargo formats, that is, Cas: single-guide RNA ribonucleoprotein, Cas mRNA and single-guide RNA, and Cas plasmid expressing CRISPR/Cas systems. The authors hope this review will help develop safe and efficient nanomaterial-based carriers for CRISPR tools.

Metal-Organic Framework-Based Nanoheater with Photo-Triggered Cascade Effects for On-Demand Suppression of Cellular Thermoresistance and Synergistic Cancer Therapy

Nanomedicine with stable light-heat conversion and spatiotemporally controllable drug activation is crucial for the success of photothermal therapy (PTT). Herein, a metal-organic framework (MOF)-based nanoheater with light-triggered multi-responsiveness is engineered to in-situ and on-demand sensitize cancer cells to local hyperthermia. Well-dispersed platinum nanoparticles synthesized inside nanospaces of the MOF are employed as the near-infrared (NIR)-harvesting unit with stable and high light-heat conversion performance. A conformation switchable polymer shell is constructed as a secondary light-responding unit to gate the targeted activation of a molecular inhibitor against thermoresistance. By cascade transformation of light stimuli to downstream signals, the nanoheater enables inhibitor release to go with local heating at the same time restricted in lesion sites to maximize efficacy and minimize systemic toxicity. The efficient photothermal conversion and the blockage of cellular heat-protective pathways provide a dual-mode of action which selectively sensitizes cancer cells to hyperthermia in a spatiotemporally controlled manner. With NIR as the remote switch, the MOF-based nanosystem demonstrates localized and boosted PTT efficacy against cancer both in vitro and in vivo. These results present nanosized MOFs as tailorable and versatile platforms for synergistic and precise cancer therapy.

Nine days extended release of adenosine from biocompatible MOFs under biologically relevant conditions

Adenosine is a small molecule directly involved in maintaining homeostasis under pathological and stressful conditions. Due to its rapid metabolism, delivery vehicles capable of exhibiting extended release of adenosine are of paramount interest. Herein, we demonstrate a superior long-term (9 days) release profile of adenosine from biocompatible MOFs in a physiologically relevant environment. The key to the biocompatibility of MOFs is their stability under biologically relevant conditions. This study additionally highlights the interplay between the chemical stability of prototypal MOFs, assessed under physiological conditions, and their cytotoxicity profiles. Cytotoxicity of the prototypal Zn-based MOF (ZIF-8) and three Zr-based MOFs (UiO-66, UiO-66-NH₂, and MOF-801) on six cell types was assessed. The cell types selected were valve interstitial cells (VICs), valve endothelial cells (VECs), adipose tissue-derived stem cells (ADSCs), and cell lines U937, THP1, and HeLa. Zr-based MOFs demonstrated a wide tolerance range in the cell culture cytotoxicity assays, demonstrating cell viability up to a very high dose of ∼1000 μg mL^-1, as compared to ZIF-8 which showed notable cytotoxicity in as little as ∼100 μg mL^-1 dose. This study demonstrates, for the first time, the utilization of biocompatible MOFs for adenosine delivery as well as establishes a direct link between structural instability in the cell culture medium and the observed cytotoxicity of the studied MOFs.

A biomimetic ZIF nanoagent for synergistic regulation of glutamine metabolism and intracellular acidosis of cancer

A homotypic cancer cell membrane camouflaged zeolitic imidazolate framework (ZIF)-based nanoagent with co-loading of two inhibitors was developed, which could suppress the efflux of protons to induce intracellular acidic stress and down-regulate glutamine metabolism to reduce the energy supply. As a compensation, glycometabolism would be upregulated with simultaneous production of large amounts of lactic acid, which could in turn aggravate the acidosis and further realize a synergetic cancer treatment.

Mitochondrial Dysfunction and Antioxidation Dyshomeostasis-Enhanced Tumor Starvation Synergistic Chemotherapy Achieved using a Metal-Organic Framework-Based Nano-Enzyme Reactor

Exploiting zeolitic imidazolate framework (ZIF)-based nanoparticles to synergistically enhance starvation-combined chemotherapy strategies remains an urgent demand. Herein, glucose oxidase (GOX) and doxorubicin (DOX) were facilely incorporated into ZIFs for starvation-combined chemotherapy. The as-prepared DOX/GOX-loaded ZIF (DGZ) exhibited uniform size with good dispersity, effective protection of the GOX activity, and stable delivery of the drugs into tumor. Correspondingly, it could achieve the glucose- and pH-responsive degradation and thus the controllable drug release. As a result, the acidification of glucose accompanied with reactive oxygen species (ROS) production was observed for the starvation-enhanced chemotherapy and the improved degradation. Most importantly, adjustable Zn²⁺ release was achieved with the biodegradation of DGZ, which thus contributed to an augmented therapeutic outcome via the Zn²⁺-induced mitochondrial dysfunction and antioxidation dyshomeostasis. These findings, synergized with the enhancement of starvation-combined chemotherapy by inhibiting the mitochondrial energy metabolism and boosting the ROS accumulation using pristine ZIF-based nanoparticles, provide a new insight into the metal-organic framework-based nanomedicine for further cancer treatments.

Synthesis and Encapsulation of Ajuga parviflora Extract with Zeolitic Imidazolate Framework-8 and Their Therapeutic Action against G+ and G- Drug-Resistant Bacteria

Infectious diseases caused by bacteria have become a public health issue. Antibiotic therapy for infectious disorders, as well as antibiotic overuse, has resulted in antibiotic-resistant bacterial strains. Zeolitic imidazolate framework-8 (ZIF-8) possesses a wide surface area, high porosity, variable functionality, and potential drug carriers. We have established a clear method for making a nanoscale APE@ZIF-8 nanocomposite agent with outstanding antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) and cephalosporin-carbapenem-resistant Escherichia coli (CCREC). We present a unique approach for encapsulating molecules ofAjuga parviflora extract (APE) with ZIF-8. APE@ZIF-8 has a positive charge. By electrostatic contact with the negatively charged bacterial surface of S. aureus and E. coli, APE@ZIF-8 NPs produce reactive oxygen species (ROS) that damage bacterial cell organelles. As a result, the APE@ZIF-8 nanocomposite offers limitless application potential in the treatment of infectious disorders caused by drug-resistant gram-positive and gram-negative bacteria.

MOF-enabled confinement and related effects for chemical catalyst presentation and utilization

A defining characteristic of nearly all catalytically functional MOFs is uniform, molecular-scale porosity. MOF pores, linkers and nodes that define them, help regulate reactant and product transport, catalyst siting, catalyst accessibility, catalyst stability, catalyst activity, co-catalyst proximity, composition of the chemical environment at and beyond the catalytic active site, chemical intermediate and transition-state conformations, thermodynamic affinity of molecular guests for MOF interior sites, framework charge and density of charge-compensating ions, pore hydrophobicity/hydrophilicity, pore and channel rigidity vs. flexibility, and other features and properties. Collectively and individually, these properties help define overall catalyst functional behaviour. This review focuses on how porous, catalyst-containing MOFs capitalize on molecular-scale confinement, containment, isolation, environment modulation, energy delivery, and mobility to accomplish desired chemical transformations with potentially superior selectivity or other efficacy, especially in comparison to catalysts in homogeneous solution environments.

Embedding an extraordinary amount of gemifloxacin antibiotic in ZIF-8 framework with one-step synthesis and measurement of its H2O2-sensitive release and potency against infectious bacteria

GEM@ZIF-8 has DLC = 69.82% and DLE = 89.03%, with controlled release dependent on H2O2 concentration, and it shows significant antibacterial activity.

Biomimetic smart nanoplatform for dual imaging-guided synergistic cancer therapy

A biomimetic nanoplatform for MRI and fluorescence imaging-guided synergetic cancer therapies has been constructed using a folate-functionalized erythrocyte membrane-coated metal–organic framework as both a photosensitizer and a nanocarrier.