Magnetic nanoscale metal organic frameworks for potential targeted anticancer drug delivery, imaging and as an MRI contrast agent

Isoreticular Metal-Organic Framework-3 (IRMOF-3): From Experimental Preparation, Functionalized Modification to Practical Applications

Isoreticular metal-organic framework-3 (IRMOF-3), a porous coordination polymer, is an MOF material with the characteristics of a large specific surface area and adjustable pore size. Due to the existence of the active amino group (-NH2) on the organic ligand, IRMOF-3 has more extensive research and application potential. Herein, the main preparation methods of IRMOF-3 in existing research were compared and discussed first. Second, we classified and summarized the functionalization modification of IRMOF-3 based on different reaction mechanisms. In addition, the expanded research and progress of IRMOF-3 and their derivatives in catalysis, hydrogen storage, material adsorption and separation, carrier materials, and fluorescence detection were discussed from an application perspective. Moreover, the industrialization prospect of IRMOF-3 and the pressing problems in its practical application were analyzed and prospected. This review is expected to provide a reference for the design and application of more new nanomaterials based on IRMOF-3 to develop more advanced functional materials in industrial production and engineering applications.

Exploring Synthesis Strategies and Interactions between MOFs and Drugs for Controlled Drug Loading and Release, Characterizing Interactions Through Advanced Techniques

This study explores various aspects of Metal-Organic Frameworks (MOFs), focusing on synthesis techniques to adjust pore size and key ligands and metals for crafting carrier MOFs. It investigates MOF-drug interactions, including hydrogen bonding, van der Waals, and electrostatic interactions, along with kinetic studies. The multifaceted applications of MOFs in drug delivery systems are elucidated. The morphology and structure of MOFs are intricately linked to synthesis methodology, impacting attributes like crystallinity, porosity, and surface area. Hydrothermal synthesis yields MOFs with high crystallinity, suitable for catalytic applications, while solvothermal synthesis generates MOFs with increased porosity, ideal for gas and liquid adsorption. Understanding MOF-drug interactions is crucial for optimizing drug delivery, affecting charge capacity, stability, and therapeutic efficacy. Kinetic studies determine drug release rates and uniformity, vital for controlled drug delivery. Overall, comprehending drug-MOF interactions and kinetics is essential for developing effective and controllable drug delivery systems.

Nanocomposites Based on Magnetic Nanoparticles and Metal-Organic Frameworks for Therapy, Diagnosis, and Theragnostics

In the last two decades, metal-organic frameworks (MOFs) with highly tunable structure and porosity, have emerged as drug nanocarriers in the biomedical field. In particular, nanoscaled MOFs (nanoMOFs) have been widely investigated because of their potential biocompatibility, high drug loadings, and progressive release. To enhance their properties, MOFs have been combined with magnetic nanoparticles (MNPs) to form magnetic nanocomposites (MNP@MOF) with additional functionalities. Due to the magnetic properties of the MNPs, their presence in the nanosystems enables potential combinatorial magnetic targeted therapy and diagnosis. In this Review, we analyze the four main synthetic strategies currently employed for the fabrication of MNP@MOF nanocomposites, namely, mixing, in situ formation of MNPs in presynthesized MOF, in situ formation of MOFs in the presence of MNPs, and layer-by-layer methods. Additionally, we discuss the current progress in bioapplications, focusing on drug delivery systems (DDSs), magnetic resonance imaging (MRI), magnetic hyperthermia (MHT), and theragnostic systems. Overall, we provide a comprehensive overview of the recent advances in the development and bioapplications of MNP@MOF nanocomposites, highlighting their potential for future biomedical applications with a critical analysis of the challenges and limitations of these nanocomposites in terms of their synthesis, characterization, biocompatibility, and applicability.

Targeted cancer treatment using folate-conjugated sponge-like ZIF-8 nanoparticles: a review

ZIF-8 (zeolitic imidazolate framework-8) is a potential drug delivery system because of its unique properties, which include a large surface area, a large pore capacity, a large loading capacity, and outstanding stability under physiological conditions. ZIF-8 nanoparticles may be readily functionalized with targeting ligands for the identification and absorption of particular cancer cells, enhancing the efficacy of chemotherapeutic medicines and reducing adverse effects. ZIF-8 is also pH-responsive, allowing medication release in the acidic milieu of cancer cells. Because of its tunable structure, it can be easily functionalized to design cancer-specific targeted medicines. The delivery of ZIF-8 to cancer cells can be facilitated by folic acid-conjugation. Hence, it can bind to overexpressed folate receptors on the surface of cancer cells, which holds the promise of reducing unwanted deliveries. As a result of its importance in cancer treatment, the folate-conjugated ZIF-8 was the major focus of this review.

Biomedical application of metal-organic frameworks (MOFs) in cancer therapy: Stimuli-responsive and biomimetic nanocomposites in targeted delivery, phototherapy and diagnosis

The nanotechnology is an interdisciplinary field that has become a hot topic in cancer therapy. Metal-organic frameworks (MOFs) are porous materials and hybrid composites consisted of organic linkers and metal cations. Despite the wide application of MOFs in other fields, the potential of MOFs for purpose of cancer therapy has been revealed by the recent studies. High surface area and porosity, significant drug loading and encapsulation efficiency are among the benefits of using MOFs in drug delivery. MOFs can deliver genes/drugs with selective targeting of tumor cells that can be achieved through functionalization with ligands. The photosensitizers and photo-responsive nanostructures including carbon dots and gold nanoparticles can be loaded in/on MOFs to cause phototherapy-mediated tumor ablation. The immunogenic cell death induction and increased infiltration of cytotoxic CD8+ and CD4+ T cells can be accelerated by MOF platforms in providing immunotherapy of tumor cells. The stimuli-responsive MOF platforms responsive to pH, redox, enzyme and ion can accelerate release of therapeutics in tumor site. Moreover, MOF nanocomposites can be modified ligands and green polymers to improve their selectivity and biocompatibility for cancer therapy. The application of MOFs for the detection of cancer-related biomarkers can participate in the early diagnosis of patients.

Preparation of size-tunable Fe3O4 magnetic nanoporous carbon composites by MOF pyrolysis regulation for magnetic resonance sensing of aflatoxin B1 with excellent anti-matrix effect

Magnetic nanoporous materials represent a new emerging category of magnetic materials for construction of magnetic resonance sensors. In this study, we adopted the metal-organic framework materials, MIL-101(Fe), as the precursor to prepare series nanoporous-carbon-Fe3O4 (NPC-Fe3O4) composites. Results showed that Fe3O4 were uniformly distributed in MIL-101(Fe) and the size of MNP was precisely tuned at different pyrolysis temperatures, conferring the optimal NPC-Fe3O4-450 °C composite with dramatically improved T2 relaxivity. The NPC-Fe3O4-450 °C composite was modified with antibodies and antigens, respectively, for detection of aflatoxin B1 in various food samples with complicated matrix. Range from 0.010 ng mL-1 to 2.0 ng mL-1, extreme low detection limit of 5.0 pg mL-1, and satisfied recoveries were successfully achieved, indicating excellent anti-matrix effect. These findings offer a new dimension to engineer novel magnetic materials with improved relaxivity for simple and easy sensing of food hazards in complicated food matrix without any purification or separation procedures.

Trajectory in biological metal-organic frameworks: Biosensing and sustainable strategies-perspectives and challenges

The ligand attribute of biomolecules to form coordination bonds with metal ions led to the discovery of a novel class of materials called biomolecule-associated metal-organic frameworks (Bio-MOFs). These biomolecules coordinate in multiple ways and provide versatile applications. Far-spread bio-ligands include nucleobases, amino acids, peptides, cyclodextrins, saccharides, porphyrins/metalloporphyrin, proteins, etc. Low-toxicity, self-assembly, stability, designable and selectable porous size, the existence of rigid and flexible forms, bio-compatibility, and synergistic interactions between metal ions have led Bio-MOFs to be commercialized in industries such as sensors, food, pharma, and eco-sensing. The rapid growth and commercialization are stunted by absolute bio-compatibility issues, bulk morphology that makes it rigid to alter shape/porosity, longer reaction times, and inadequate research. This review elucidates the structural vitality, biocompatibility issues, and vital sensing applications, including challenges for incorporating bio-ligands into MOF. Critical innovations in Bio-MOFs' applicative spectrum, including sustainable food packaging, biosensing, insulin and phosphoprotein detection, gas sensing, CO2 capture, pesticide carriers, toxicant adsorptions, etc., have been elucidated. Emphasis is placed on biosensing and biomedical applications with biomimetic catalysis and sensitive sensor designing.

Magnetic UiO-66-NH2 Core-Shell Nanohybrid as a Promising Carrier for Quercetin Targeted Delivery toward Human Breast Cancer Cells

In this study, a magnetic core-shell metal-organic framework (MOF) nanocomposite, Fe3O4-COOH@UiO-66-NH2, was synthesized for tumor-targeting drug delivery by incorporating carboxylate groups as functional groups onto ferrite nanoparticle surfaces, followed by fabrication of the UiO-66-NH2 shell using a facile self-assembly approach. The anticancer drug quercetin (QU) was loaded into the magnetic core-shell nanoparticles. The synthesized magnetic nanoparticles were comprehensively evaluated through multiple techniques, including FT-IR, PXRD, FE-SEM, TEM, EDX, BET, UV-vis, ZP, and VSM. Drug release investigations were conducted to investigate the release behavior of QU from the nanocomposite at two different pH values (7.4 and 5.4). The results revealed that QU@Fe3O4-COOH@UiO-66-NH2 exhibited a high loading capacity of 43.1% and pH-dependent release behavior, maintaining sustained release characteristics over a prolonged duration of 11 days. Furthermore, cytotoxicity assays using the human breast cancer cell line MDA-MB-231 and the normal cell line HEK-293 were performed to evaluate the cytotoxic effects of QU, UiO-66-NH2, Fe3O4-COOH, Fe3O4-COOH@UiO-66-NH2, and QU@Fe3O4-COOH@UiO-66-NH2. Treatment with QU@Fe3O4-COOH@UiO-66-NH2 substantially reduced the cell viability in cancerous MDA-MB-231 cells. Cellular uptake and cell death mechanisms were further investigated, demonstrating the internalization of QU@Fe3O4-COOH@UiO-66-NH2 by cancer cells and the induction of cancer cell death through the apoptosis pathway. These findings highlight the considerable potential of Fe3O4-COOH@UiO-66-NH2 as a targeted nanocarrier for the delivery of anticancer drugs.

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.

Co-delivery of doxorubicin/sorafenib by DNA-decorated green ZIF-67-based nanocarriers for chemotherapy and hepatocellular carcinoma treatment

Zeolitic imidazolate framework-67 (ZIF-67) has been decorated with natural biomaterials and DNA to develop a promising strategy and suitable and safe co-delivery platform for doxorubicin and sorafenib (DOX-SOR). FT-IR, XRD, FESEM, and TEM were used to characterize the modified MOFs. Combined Ginkgo biloba leaf extract and E. coli DNA were used as green decorations, and as environmentally-friendly methods to be developed, and DOX and SOR were attached to the porosity and on the surface of the MOFs. TEM and FESEM images demonstrated that the green MOFs were successfully synthesized for biomedical applications and showed their cubic structure. As a result of the nanocarrier-drug interactions, 59.7% and 60.2% of the drug payload were achieved with DOX and SOR, respectively. HEK-293, HT-29, and MCF-7 cells displayed excellent viability by decoration with DNA and Ginkgo biloba leaf extract at low and high concentrations (0.1 and 50 μg/mL), suggesting they could be used in biomedical applications. MTT assays demonstrated that the nanocarriers are highly biocompatible with normal cells and possess anticancer properties when applied to HT-29 and MCF-7 cells. As a result of Ginkgo biloba leaf extract and DNA modification, DOX-SOR release was prolonged and pH-sensitive (highest release at pHs 4.5 and 5.5). The internalization and delivery of the drug were also studied using a 2d fluorescence microscope, demonstrating that the drug was effectively internalized. Cell images showed NPs internalizing in MCF-7 cells, proving their efficacy as drug delivery systems.

Smart Nanomaterials in Cancer Theranostics: Challenges and Opportunities

Cancer is ranked as the second leading cause of death globally. Traditional cancer therapies including chemotherapy are flawed, with off-target and on-target toxicities on the normal cells, requiring newer strategies to improve cell selective targeting. The application of nanomaterial has been extensively studied and explored as chemical biology tools in cancer theranostics. It shows greater applications toward stability, biocompatibility, and increased cell permeability, resulting in precise targeting, and mitigating the shortcomings of traditional cancer therapies. The nanoplatform offers an exciting opportunity to gain targeting strategies and multifunctionality. The advent of nanotechnology, in particular the development of smart nanomaterials, has transformed cancer diagnosis and treatment. The large surface area of nanoparticles is enough to encapsulate many molecules and the ability to functionalize with various biosubstrates such as DNA, RNA, aptamers, and antibodies, which helps in theranostic action. Comparatively, biologically derived nanomaterials perceive advantages over the nanomaterials produced by conventional methods in terms of economy, ease of production, and reduced toxicity. The present review summarizes various techniques in cancer theranostics and emphasizes the applications of smart nanomaterials (such as organic nanoparticles (NPs), inorganic NPs, and carbon-based NPs). We also critically discussed the advantages and challenges impeding their translation in cancer treatment and diagnostic applications. This review concludes that the use of smart nanomaterials could significantly improve cancer theranostics and will facilitate new dimensions for tumor detection and therapy.

Synthesis and characterization of a smart polymer-coated core–shell MnFe2O4@ organometallic framework for targeted drug delivery

Scientists are currently working to develop more effective and less harmful methods of delivering drugs to tissue. One method is to use a special type of carrier to help the drug get to the right place in the body. In this study, an organometallic framework nanocarrier with the formula IRMOF-3 [Zn4O(NH2-BDC)3] was successfully prepared, containing magnetic nanoparticles of manganese ferrite (MnFe2O4) and the drug doxorubicin encapsulated in a pH- and temperature-sensitive smart polymer of poly-N-isopropylacrylamide. Doxorubicin, an anticancer drug, was loaded into the pores of a magnetic organometallic framework and modified with the smart polymer poly(N-isopropylacrylamide-co-AA), which has a lower critical solution temperature (LCST) of less than 38 °C. The synthesis of magnetic nanoparticles and magnetic organometallic frameworks encapsulated in smart polymer was investigated using various analytical techniques such as Fourier transform infrared spectrometer, thermal stability analysis, BET, and VSM. The particles in the synthesized nanocarrier are uniform in size, have high magnetic properties, and are thermally stable. The effective surface area is 7.26 m2/g, and the pore volume is 166.394 m. The drug carrier has the ability to load up to 78% of the drug into the solution. The highest drug release was observed when the pH was 5 and the temperature was higher than the LCST. 71% of cancer cells were destroyed by the drug carrier in the culture medium. This nanosystem, designed with more drug retention, reduced side effects and controlled release in different conditions, is suitable as a drug delivery system.

Highly improved pH-Responsive anticancer drug delivery and T2-Weighted MRI imaging by magnetic MOF CuBTC-based nano/microcomposite

Cu-BTC framework has received a considerable attention in recent years as a drug carrier candidate for cancer treatment due to its unique structural properties and promising biocompatibility. However, its intrinsic deficiency for medical imaging potentially limits its bioapplications; To address this subject, a magnetic nano/microscale MOF has been successfully fabricated by introducing Fe₃O₄ nanoparticles as an imaging agent into the porous isoreticular MOF [Cu₃(BTC)₂] as a drug carrier. The synthesized magnetic MOFs exhibits a high loading capacity (40.5%) toward the model anticancer DOX with an excellent pH-responsive drug release. The proposed nanocomposite not only possesses large surface area, high magnetic response, large mesopore volume, high transverse relaxivity (r ²) and good stability but also exhibits superior biocompatibility, specific tumor cellular uptake, and significant cancer cell viability inhibitory effect without any targeting agent. It is expected that the synthesized magnetic nano/microcomposite may be used for clinical purposes and can also serve as a platform for photoactive antibacterial therapy ae well as pH/GSH/photo-triple-responsive nanocarrier.

Recent Advances of Anticancer Studies Based on Nano-Fluorescent Metal-Organic Frameworks

Nano-fluorescent metal-organic frameworks (NF-MOFs), a kind of newly emerged nano-scaled platform, can provide visual, rapid, and highly sensitive optical imaging of cancer lesions both in vitro and in vivo. Meanwhile, the excellent porosity, structural tunability, and chemical modifiability also enable NF-MOFs to achieve simultaneous loading of targeted molecules and therapeutic agents. These NF-MOFs not only possess excellent targeted imaging ability, but also can guide the carried cargos to perform precise therapy, drawing considerable attention in current framework of anticancer drug design. In this review, we outline the fluorescence types and response mechanisms of NF-MOFs, and highlight their applications in cancer diagnosis and therapy in recent years. Based on this panorama, we also discuss current issues and future trends of NF-MOFs in biomedical fields, attempting to clarify the potential value of fluorescence imaging guided anticancer investigations.

Fabrication of Functional bioMOF-100 Prototype as Drug Delivery System for Breast Cancer Therapy

Breast cancer is the most frequent cause of cancer death in women, representing the fifth leading cause of cancer death overall. Therefore, the growing search for the development of new treatments for breast cancer has been developed lately as well as drug delivery systems such as biocompatible metal-organic Frameworks (bio-MOFs). These may be promising and attractive for drug incorporation and release. The present study aims to develop a drug carrier system RCA (bioMOF-100 submitted to the activation process) containing incorporated curcumin (CCM), whose material surface is coated with folic acid molecules (FA) to promote the targeting of drug carrier systems to the tumor region. They were synthesized and characterized using several characterization techniques. The materials were submitted to drug encapsulation tests, whose encapsulation efficiency was 32.80% for CCM@RCA-1D. Using the ¹H nuclear magnetic resonance (NMR) spectroscopy technique, it was possible to verify the appearance of signals referring to folic acid, suggesting success in the functionalization of these matrices. In vitro tests such as cell viability and type of cell death were evaluated in both series of compounds (CCM@RCA-1D, CCM@RCA-1D/FA) in breast tumor lines. The results revealed low toxicity of the materials and cell death by late apoptosis. Thus, these results indicate that the matrices studied can be promising carriers in the treatment of breast cancer.

Application of MOF-based nanotherapeutics in light-mediated cancer diagnosis and therapy

Light-mediated nanotherapeutics have recently emerged as promising strategies to precisely control the activation of therapeutic reagents and imaging probe both in vitro and in vivo, largely ascribed to their unique properties, including minimally invasive capabilities and high spatiotemporal resolution. Nanoscale metal-organic frameworks (NMOFs), a new family of hybrid materials consisting of metal attachment sites and bridging ligands, have been explored as a new platform for enhanced cancer diagnosis and therapy due to their tunable size, modifiable surface, good biocompatibility, high agent loading and, most significantly, their ability to be preferentially deposited in tumors through enhanced permeability and retention (EPR). Especially the light-driven NMOF-based therapeutic platform, which not only allow for increased laser penetration depth and enhanced targeting, but also enable imaging-guided or combined treatments. This review provides up-to-date developments of NMOF-based therapeutic platforms for cancer treatment with emphasis on light-triggered therapeutic strategies and introduces their advances in cancer diagnosis and therapy in recent years.

Aperture Modulation of Isoreticular Metal Organic Frameworks for Targeted Antitumor Drug Delivery

The introduction of different pore diameters in metal organic frameworks (MOFs) could adjust their drug delivery performance. MOFs with customized structures have potential application value in targeted drug delivery. However, no research on this topic has been found so far. In this report, isoreticular metal organic frameworks (IRMOFs) have been taken as a typical case of tailor-made MOFs, the pore size of which is enlarged (average BJH pore sizes of about 2.43, 3.06, 5.47, and 6.50 nm were determined for IRMOF-1, IRMOF-8, IRMOF-10, and IRMOF-16, respectively), emphasizing the relationship between pore size and model drugs (Oridonin, ORI) and clarifying its potential working mechanism. IRMOF-1, whose pore size matches the size of ORI, has an outstanding drug loading capacity (57.93% by wt) and release profile (about 90% in 24 h at pH 7.4). IRMOF-1 was further coated with polyethylene glycol (PEG) modified with a cell penetrating peptide (CPP44) bound to M160 (CD163L1) protein for targeting of hepatic tumor lines. This nanoplatform (CPP44-PEG@ORI@IRMOF-1) exhibited acid-responsive drug release behavior (37.86% in 10 h at pH 7.4 and 66.66% in 10 h at pH 5.5) and significantly enhanced antitumor effects. The results of cell targeting and in vivo animal imaging indicated that CPP44-PEG@ORI@IRMOF-1 may serve as a tumor-selective drug delivery nanoplatform. Toxicity assessment confirmed that PEGylated IRMOF-1 did not cause organ or systemic toxicity. Furthermore, it is encouraging that the IRMOF-based targeted drug delivery system with pore size modulation showed rapid clearance (most administered NPs are metabolized from urine and feces within 1 week) and avoided accumulation in the body, indicating their promise for biomedical applications. This MOF-based aperture modulation combined with a targeted modification strategy might find broad applications in cancer theranostics. Thus, it is convenient to customize personalized MOFs according to the size of drug molecules in future research.

The uptake of metal-organic frameworks: a journey into the cell

The application of metal-organic frameworks (MOFs) in drug delivery has advanced rapidly over the past decade, showing huge progress in the development of novel systems. Although a large number of versatile MOFs that can carry and release multiple compounds have been designed and tested, one of the main limitations to their translation to the clinic is the limited biological understanding of their interaction with cells and the way they penetrate them. This is a crucial aspect of drug delivery, as MOFs need to be able not only to enter into cells but also to release their cargo in the correct intracellular location. While small molecules can enter cells by passive diffusion, nanoparticles (NPs) usually require an energy-dependent process known as endocytosis. Importantly, the fate of NPs after being taken up by cells is dependent on the endocytic pathways they enter through. However, no general guidelines for MOF particle internalization have been established due to the inherent complexity of endocytosis as a mechanism, with several factors affecting cellular uptake, namely NP size and surface chemistry. In this review, we cover recent advances regarding the understanding of the mechanisms of uptake of nano-sized MOFs (nanoMOFs)s, their journey inside the cell, and the importance of biological context in their final fate. We examine critically the impact of MOF physicochemical properties on intracellular trafficking and successful cargo delivery. Finally, we highlight key unanswered questions on the topic and discuss the future of the field and the next steps for nanoMOFs as drug delivery systems.

Separation of Volatile Organic Compounds in TAMOF-1

Separation of volatile organic compounds is one of the most studied processes in industry. TAMOF-1 is a homochiral metal-organic framework with a crystalline network of interconnected ≈1 nm channels and has high thermal and chemical stability. Thanks to these features, it can resolve racemic mixtures of chiral drugs as a chiral stationary phase in chromatography. Interestingly, the particular shape and size of its channels, along with the presence of metallic centers and functional groups, allow establishing weak but significant interactions with guest molecules. This opens interesting possibilities not only to resolve racemates but also to separate other organic mixtures, such as saturated/unsaturated and/or linear/branched molecules. In search of these applications, we have studied the separation of volatile organic compounds in TAMOF-1. Monte Carlo simulations in the grand-canonical ensemble have been carried out to evaluate the separation of the selected molecules. Our results predict that TAMOF-1 is able to separate xylene isomers, hexane isomers, and benzene-cyclohexane mixtures. Experimental breakthrough analysis in the gas phase and also in the liquid phase confirms these predictions. Beds of TAMOF-1 are able to recognize the substitution in xylenes and the branching in hexanes, yielding excellent separation and reproducibility, thanks to the chemical and mechanical features of this material.

Decorated bacteria and the application in drug delivery

The use of living bacteria either as therapeutic agents or drug carriers has shown great potential in treating a multitude of intractable diseases. However, cells are often fragile to unfriendly environmental stressors and limited by inadequately therapeutic responses, leading to unwanted cell death and a decline in treatment efficacy. Surface decoration of bacteria has emerged as a simple yet useful strategy that not only confers bacteria with extra capacity to resist environmental threats but also endows them with exogenous characteristics that are neither inherent nor naturally achievable. In this review, we systematically introduce the advancements of physicochemical and biological technologies for surface modification of bacteria, especially the single-cell surface decoration strategies of individual bacteria. We highlight the recent progress on surface decoration that aims to improve the bioavailability and efficacy of therapeutic bacterial agents and also to achieve enhanced and targeted delivery of conventional drugs. The promises along with challenges of surface-decorated bacteria as drug delivery systems for applications in cancer therapy, intestinal disease treatment, bioimaging, and diagnosis are further discussed with respect to future clinical translation. This review offers an overview of the advances of decorated bacteria for drug delivery applications and would contribute to the development of the next generation of advanced bacterial-based therapies.

Synthesis of green benzamide-decorated UiO-66-NH2 for biomedical applications

Metal-organic frameworks (MOFs) biocompatible systems can host enzymes/bacteria/viruses. Herein we synthesized a series of fatty acid amide hydrolase (FAAH)-decorated UiO-66-NH₂ based on Citrus tangerine leaf extract for drug delivery and biosensor applications. Five chemically manipulated FAAH-like benzamides were localized on the UiO-66-NH₂ surface with physical interactions. Comprehensive cellular and molecular analyses were conducted on HEK-293, HeLa, HepG2, PC12, MCF-7, and HT-29 cell lines (cytotoxicity assessment after 24 and 48 h). MTT results proved above 95 and 50% relative cell viability in the absence and presence of the drug, respectively. A complete targeted drug-releasing capability of nanocarriers was demonstrated after capping with leaf extract from Citrus tangerine, with a stimuli-responsive effect in acidic media. Targeted delivery was complete to the nucleus and cytoplasm of HT-29 cell, but merely to the cytoplasm of HeLa cell lines. Nanocarrier could be targeted for drug delivery to the cytoplasm of the HeLa cell line and to both the nucleus and cytoplasm of HT-29 cell lines. MOF-based nanocarriers proved authentic in vivo towards kidney and liver tissues with targeted cancerous cells efficiently. Besides, FAAH-like molecules revealed optical biosensor potential with high selectivity (even ˂5 nM LOD) towards ssDNA, sgRNA, and Anti-cas9 proteins.

Porous Colloidal Nanoparticles as Injectable Multimodal Contrast Agents for Enhanced Geophysical Sensing

Injecting fluids into underground geologic structures is crucial for the development of long-term strategies for managing captured carbon and facilitating sustainable energy extraction operations. We have previously reported that the injection of metal-organic frameworks (MOFs) into the subsurface can enhance seismic monitoring tools to track fluids and map complex structures, reduce risk, and verify containment in carbon storage reservoirs because of their absorption capacity of low-frequency seismic waves. Here, we demonstrate that water-based Cr/Zn/Zr MOF colloidal suspensions (nanofluids) are multimodal geophysical contrast agents that enhance near-wellbore logging tools. Based on experimental fluid-only measurements, MIL-101(Cr), ZIF-8, and UiO-66 nanofluids have distinct complex conductivity and/or low-field nuclear magnetic resonance (NMR) signatures that are relevant to field-deployed technologies, implying the potential to enhance near-wellbore monitoring of CO2 injection and associated processes with downhole logging tools. Small- and wide-angle X-ray scattering characterization of ∼0.5 wt % MIL-101(Cr) suspensions confirmed phase stability and provided insight into the fractal nature of colloidal nanoparticles. Finally, low-field (2 MHz) NMR measurements of MIL-101(Cr) nanofluid injection into a prototypical Berea sandstone demonstrate how paramagnetic high-surface area MOFs may dominate the relaxation times of hydrogen-bearing fluids in porous geologic matrices, enhancing the mapping of near-surface and near-wellbore transport pathways and advancing sustainable subsurface energy technologies.

Nanoscale Metal−Organic Frameworks and Their Nanomedicine Applications

Abundant connectivity among organic ligands and inorganic metal ions makes the physical and chemical characters of metal-organic frameworks (MOFs) could be precisely devised and modulated for specific applications. Especially nanoscale MOFs (NMOFs), a unique family of hybrid nanomaterials, with merits of holding the nature as the mainstay MOFs and demonstrating particle size in nanoscale range which enable them prospect platform in clinic. Adjustability of composition and structure allows NMOFs with different constituents, shapes, and characteristics. Oriented frameworks and highly porous provide enough space for packing therapeutic cargoes and various imaging agents efficiently. Moreover, the relatively labile metal-ligand bonds make NMOFs biodegradable in nature. So far, as a significant class of biomedically relevant nanomaterials, NMOFs have been explored as drug carriers, therapeutic preparation, and biosensing and imaging preparation owing to their high porosity, multifunctionality, and biocompatibility. This review provides up-to-date developments of NMOFs in biomedical applications with emphasis on size control, synthetic approaches, and surfaces functionalization as well as stability, degradation, and toxicity. The outlooks and several crucial issues of this area are also discussed, with the expectation that it may help arouse widespread attention on exploring NMOFs in potential clinical applications.

Current status and future prospects of nanoscale metal–organic frameworks in bioimaging

The importance of diagnosis and in situ monitoring of lesion regions and transportation of bioactive molecules has a pivotal effect on successful treatment, reducing side effects, and increasing the chances of survival in the case of diseases.

Zinc-Based Metal-Organic Frameworks in Drug Delivery, Cell Imaging, and Sensing

The design and structural frameworks for targeted drug delivery of medicinal compounds and improved cell imaging have been developed with several advantages. However, metal-organic frameworks (MOFs) are supplemented tremendously for medical uses with efficient efficacy. These MOFs are considered as an absolutely new class of porous materials, extensively used in drug delivery systems, cell imaging, and detecting the analytes, especially for cancer biomarkers, due to their excellent biocompatibility, easy functionalization, high storage capacity, and excellent biodegradability. While Zn-metal centers in MOFs have been found by enhanced efficient detection and improved drug delivery, these Zn-based MOFs have appeared to be safe as elucidated by different cytotoxicity assays for targeted drug delivery. On the other hand, the MOF-based heterogeneous catalyst is durable and can regenerate multiple times without losing activity. Therefore, as functional carriers for drug delivery, cell imaging, and chemosensory, MOFs' chemical composition and flexible porous structure allowed engineering to improve their medical formulation and functionality. This review summarizes the methodology for fabricating ultrasensitive and selective Zn-MOF-based sensors, as well as their application in early cancer diagnosis and therapy. This review also offers a systematic approach to understanding the development of MOFs as efficient drug carriers and provides new insights on their applications and limitations in utility with possible solutions.

Recent development of metal-organic framework nanocomposites for biomedical applications

Albeit metal-organic framework (MOF) composites have been extensively explored, reducing the size and dimensions of various contents within the composition, to the nanoscale regime, has recently presented unique opportunities for enhanced properties with the formation of MOF-based nanocomposites. Many distinctive strategies have been used to fabricate these nanocomposites such as through the introduction of nanoparticles (NPs) into a MOF precursor solution or vice versa to achieve a core-shell or heterostructure configuration. As such, MOF-based nanocomposites offer seemingly limitless possibilities and promising solutions for the vast range of applications across biomedical disciplines especially for improving in vivo implementation. In this review, we focus on the recent development of MOF-based nanocomposites, outline their classification according to the type of integrations (NPs, coating materials, and different MOF-derived nanocomposites), and direct special attention towards the various approaches and strategies employed to construct these nanocomposites for their prospective utilization in biomedical applications including biomimetic enzymes and photo, chemo, sonodynamic, starvation and hyperthermia therapies. Lastly, our work aims to highlight the exciting potential as well as the challenges of MOF-based nanocomposites to help guide future research as well as to contribute to the progress of MOF-based nanotechnology in biomedicine.

Metal-Organic Frameworks (MOFs) for Cancer Therapy

MOFs exhibit inherent extraordinary features for diverse applications ranging from catalysis, storage, and optics to chemosensory and biomedical science and technology. Several procedures including solvothermal, hydrothermal, mechanochemical, electrochemical, and ultrasound techniques have been used to synthesize MOFs with tailored features. A continued attempt has also been directed towards functionalizing MOFs via "post-synthetic modification" mainly by changing linkers (by altering the type, length, functionality, and charge of the linkers) or node components within the MOF framework. Additionally, efforts are aimed towards manipulating the size and morphology of crystallite domains in the MOFs, which are aimed at enlarging their applications window. Today's knowledge of artificial intelligence and machine learning has opened new pathways to elaborate multiple nanoporous complex MOFs and nano-MOFs (NMOFs) for advanced theranostic, clinical, imaging, and diagnostic purposes. Successful accumulation of a photosensitizer in cancerous cells was a significant step in cancer therapy. The application of MOFs as advanced materials and systems for cancer therapy is the main scope beyond this perspective. Some challenging aspects and promising features in MOF-based cancer diagnosis and cancer therapy have also been discussed.

PEGylated Nanoscale Metal-Organic Frameworks for Targeted Cancer Imaging and Drug Delivery

Nanoscale metal-organic frameworks (nMOFs) are a unique type of hybrid materials, which are broadly applicable as cargo delivery systems. However, the relatively low material stability and insufficient cancer cell interacting capacity have limited nMOFs' applications in cancer theranostics. Herein, a zirconium-based nMOF UiO-66-N3 was synthesized, and its surface was covalently functionalized with alkyne-containing polyethylene glycol (PEG) via the azide-alkyne click chemistry. After that, F3 peptide was attached for targeting of cancer cells (the material was denoted as UiO-66-PEG-F3). Doxorubicin (DOX) served as a therapeutic drug and a fluorescent label in this study, and it was transported into UiO-66-PEG conjugates with sufficient drug loading efficiency. pH-responsive release of DOX from UiO-66 conjugates was witnessed. The structural integrity of UiO-66-N3 was maintained post the surface modification process. Flow cytometry and confocal fluorescence microscopy revealed that DOX/UiO-66-PEG-F3 had stronger accumulation in MDA-MB-231 cells (nucleolin+) compared with DOX/UiO-66-PEG. In order to track the pharmacokinetic behavior (organ distribution profile) in vivo, the positron-emitting zirconium-89 (89Zr) was incorporated into UiO-66-N3. Similar PEGylation and F3 peptide conjugation resulted in the formation of 89Zr-UiO-66-PEG-F3. Serial positron emission tomography (PET) imaging demonstrated that the preferential accumulation of 89Zr-UiO-66-PEG-F3 in MDA-MB-231 tumors, and their liver clearance was faster than PEGylated UiO-66 using noncovalent methods. Thus, the PEGylated nMOFs using covalent strategies may find broad application in future cancer theranostics.

Tb3+-Doped Ag-MOFs for fluorescent detection of formaldehyde in a novel smartphone platform and its removal applications in milk products and wastewater

As one kind of reactive carbonyl species (RCS), formaldehyde (FA) with a high concentration could be extremely toxic to living bodies as well as the environment. This paper reports a three-dimensional (3D) Tb3+@Ag-MOFs-based fluorescent probe for fast sensing of FA, which uses a novel turn-on mechanism based on the luminescence induced by Tb3+. The MOF sensor shows broad dynamic ranges of 0.1-1 mM for FA with the detection limit of 1.9 μM. For online and real-time detection of FA, a portable smartphone platform was employed to analyze the RGB values of the fluorescence by a smartphone application. By incorporating this probe into a polyacrylonitrile (PAN) layer, we synthesized a film composite that could effectively remove FA in real samples including milk and chemical factory wastewater, and the removal rate reached 98.52% and 95.38% respectively. Moreover, the potential of the film to remove gaseous FA was confirmed by experiments as well.

Cu (II)-porphyrin metal-organic framework/graphene oxide: synthesis, characterization, and application as a pH-responsive drug carrier for breast cancer treatment

A new multifunctional graphene oxide/Cu (II)-porphyrin MOF nanocomposite (CuG) comprised of Cu-TCPP MOF supported on graphene oxide (GO) nanosheets, has been fabricated by a solvothermal method at low temperature and one-pot process. Cu-TCPP MOF with universal advantages, such as high porosity, nontoxicity, large surface area, and safe biodegradation, combined with GO allows the achievement of an efficient doxorubicin loading (45.7%) and smart pH-responsive release for chemotherapy. More significantly, more than 97% of DOX was released by CuG at pH 5 which was more than that at pH 7.4 (~ 33.5%), while Cu-TCPP MOF displayed DOX release of 68.5% and 49% at pH 5 and 7.4, respectively, illustrating the effect of GO on the smart MOF construction for controllable releasing behavior in vitro. The results of in vitro anticancer experiments demonstrate that the developed nanocarrier exhibited slight or no cytotoxicity on normal cells, while the drug-loaded nanocarrier increased significant cancer cell-killing ability with higher therapeutic efficacy than free DOX, indicating the sustained release behavior of the CuG nanocarrier without any "burst effect". Moreover, the in vivo experiments demonstrated that the CuG-DOX exhibited significantly higher anticancer efficiency compared with free DOX. High anti-cancer therapeutic efficacy of this nanoscale carrier as an efficient pH sensitive agent, has the potential to enter further biomedical investigations. A new smart multifunctional graphene oxide-Cu (II)-porphyrin MOF nanocomposite (CuG) formed of Cu-TCPP MOF and graphene oxide (GO) has successfully fabricated and demonstrated an efficient pH-responsive drug release behavior in cancer therapy without using any targeting ligand.

Metal-Organic Frameworks-Based Nanomaterials for Drug Delivery

The composition and topology of metal-organic frameworks (MOFs) are exceptionally tailorable; moreover, they are extremely porous and represent an excellent Brunauer-Emmett-Teller (BET) surface area (≈3000-6000 m2·g-1). Nanoscale MOFs (NMOFs), as cargo nanocarriers, have increasingly attracted the attention of scientists and biotechnologists during the past decade, in parallel with the evolution in the use of porous nanomaterials in biomedicine. Compared to other nanoparticle-based delivery systems, such as porous nanosilica, nanomicelles, and dendrimer-encapsulated nanoparticles, NMOFs are more flexible, have a higher biodegradability potential, and can be more easily functionalized to meet the required level of host-guest interactions, while preserving a larger and fully adjustable pore window in most cases. Due to these unique properties, NMOFs have the potential to carry anticancer cargos. In contrast to almost all porous materials, MOFs can be synthesized in diverse morphologies, including spherical, ellipsoidal, cubic, hexagonal, and octahedral, which facilitates the acceptance of various drugs and genes.

Folic acid-functionalized gadolinium-loaded phase transition nanodroplets for dual-modal ultrasound/magnetic resonance imaging of hepatocellular carcinoma

Dual-modal molecular imaging by combining two imaging techniques can provide complementary information for early cancer diagnosis and therapeutic monitoring. In the present manuscript, folic acid (FA)-functionalized gadolinium-loaded nanodroplets (NDs) are introduced as dual-modal ultrasound (US)/magnetic resonance (MR) imaging contrast agents. These phase-change contrast agents (PCCAs) with alginate (Alg) stabilizing shell and a liquid perfluorohexane (PFH) core were successfully synthesized via the nano-emulsion method and characterized. In this regard, mouse hepatocellular carcinoma (Hepa1-6) as target cancer cells and mouse fibroblast (L929) as control cells were used. The in vitro and in vivo cytotoxicity assessments indicated that Gd/PFH@Alg and Gd/PFH@Alg-FA nanodroplets are highly biocompatible. Gd-loaded NDs do not induce organ toxicity, and no significant hemolytic activity in human red blood cells is observed. Additionally, nanodroplets exhibited strong ultrasound signal intensities as well as T₁-weighted MRI signal enhancement with a high relaxivity value of 6.40 mM^-1 s^-1, which is significantly higher than that of the clinical Gadovist contrast agent (r₁ = 4.01 mM^-1 s^-1). Cellular uptake of Gd-NDs-FA by Hepa1-6 cancer cells was approximately 2.5-fold higher than that of Gd-NDs after 12 h incubation. Furthermore, in vivo results confirmed that the Gd-NDs-FA bound selectively to cancer cells and were accumulated in the tumor region. In conclusion, Gd/PFH@Alg-FA nanodroplets have great potential as US/MR dual-modal imaging nanoprobes for the early diagnosis of cancer.

Synthesis of the magnetic core-shell bi-metallic and tri-metallic metal-organic framework nanocomposites for dye adsorption

Bi-metallic and tri-metallic metal-organic frameworks (MOFs) supported on the magnetic activated carbon (MAC) were synthesized for the reduction of methylene blue (MB) concentration in the aqueous solutions. The adsorbent nanocomposites were characterized by applying the general tests including XRD, FTIR, FESEM, TEM, BET, and VSM. The XRD achievements demonstrated that crystalline structure of MOFs was derived on the MAC by the presented method. The core-shell morphology with nano-scale size of the magnetic carbonaceous MOFs was detected in TEM and FESEM micro-images. The acceptable magnetic strength of the prepared adsorbents was proved by using the VSM analysis. The important operating conditions including pH and temperature were also evaluated, while the other parameters were kept constant. The pseudo-second-order kinetic model was matched with the experimental data to show the kinetic behavior of the multi-component MOFs. The isotherm studies showed that the good agreement between the experimental data with both Langmuir model and the maximum capacities was calculated to be about 66.51 and 71.43 mg/g for the bi-metallic and tri-metallic nanocomposites, respectively. Regeneration experiments indicated that the fabricated adsorbents have an excellent reusing adsorption capacity which can be a proper selection for the industrial applications. PRACTITIONER POINTS: Bi-metallic and tri-metallic MOFs supported on the magnetic activated carbon were synthesized by the facile preparation method. Adsorption of methylene blue by using MOFs were successfully done. Nanocomposites were evaluated by XRD, FTIR, BET, FESEM, TEM, and VSM techniques. Maximum of adsorption capacity was observed for tri-metallic MOF as 71.43 mg/g.

Recent advances in porous nanostructures for cancer theranostics

Porous nanomaterials with high surface area, tunable porosity, and large mesopores have recently received particular attention in cancer therapy and imaging. Introduction of additional pores to nanostructures not only endows the tunability of optoelectronic and optical features optimal for tumor treatment, but also modulates the loading capacity and controlled release of therapeutic agents. In recognition, increasing efforts have been made to fabricate various porous nanomaterials and explore their potentials in oncology applications. Thus, a systematic and comprehensive summary is necessary to overview the recent progress, especially in last ten years, on the development of various mesoporous nanomaterials for cancer treatment as theranostic agents. While outlining their individual synthetic mechanisms after a brief introduction of the structures and properties of porous nanomaterials, the current review highlighted the representative applications of three main categories of porous nanostructures (organic, inorganic, and organic-inorganic nanomaterials). In each category, the synthesis, representative examples, and interactions with tumors were further detailed. The review was concluded with deliberations on the key challenges and future outlooks of porous nanostructures in cancer theranostics.

Delivery of oxaliplatin to colorectal cancer cells by folate-targeted UiO-66-NH2

Oxaliplatin is being used in different malignancies and several side effects are reported for patients taking Oxaliplatin, including peripheral neuropathy, nausea and vomiting, diarrhea, mouth sores, low blood counts, fatigue, loss of appetite, etc. Here we have developed a targeted anticancer drug delivery system based on folate-conjugated amine-functionalized UiO-66 for the delivery of oxaliplatin (OX). UiO-66-NH₂ (U) and UiO-66-NH₂-FA(FU) were pre-functionalized by the incorporation of folic acid (FA) into the structure via coordination of the carboxylate group of FA. The FTIR spectra of drug-loaded U and FU showed the presence of new carboxylic and aliphatic groups of OX and FA. Powder X-ray diffraction (PXRD) patterns were matched accordingly with the reference pattern and FESEM results showed semi-spherical particles (115-128 nm). The evaluated amounts of OX in U and FU were calculated 304.5 and 293 mg/g_, respectively. The initial burst release of OX was 15.7% per hour for U(OX) and 10.8% per hour for FU(OX). The final release plateau gives 62.9% and 52.3% for U(OX) and FU(OX). To evaluate the application of the prepared delivery platform, they were tested on colorectal cancer cells (CT-26) via MTT assay, cell migration assay, and spheroid model. IC₅₀ values obtained from MTT assay were 21.38, 95.50, and 18.20 μg/mL for OX, U(OX), and FU(OX), respectively. After three days of treatment, the CT26 spheroids at two doses of 500 and 50 μg/mL of U(OX) and FU(OX) showed volume reduction. Moreover, the oxidative behavior of the prepared systems within the cell was assessed by total thiol, malondialdehyde, and superoxide dismutase activity. The results showed that FU(OX) had higher efficacy in preventing the growth of CT-26 spheroid, and was more effective than oxaliplation in cell migration inhibition, and induced higher oxidative stress and apoptosis.

Current Status and Emerging Trend of Nanoshuttle in Biological Applications

Nanoshuttles are unique structures that resemble double-headed arrows or a nanorod with sharp tips for better penetration into the tumor cells, reduction of toxicity and minimization of off-targeting effect. These biologically- inspired multimetallic or bimetallic nano swimmers are capable of transporting cargoes from one end to another via self-propulsion in an efficient manner. Encapsulation with pH- and heat-sensitive polymers allows nanoshuttles to release cargos at the targeted site in a controlled fashion. This review article focuses on the methods of preparation and characterization of nanoshuttles with applications in the field of antineoplastic, antibacterial, erectile dysfunction, electrochemical biosensing, anticounterfeiting, on-demand and targeted delivery system for imaging as well as cell ablation therapy. Magnetic nanoshuttles exhibit modified optical properties for utilization in diagnostic imaging for sensitive and early diagnosis of diseases. Smart drug delivery is achieved when nanoshuttles are combined with nanomotors to exhibit distinctive, rapid and unidirectional movement in the bloodstream. Cost-effective synthesis of nanoshuttles will extend their applications in the commercial sectors by overcoming the limitations like scale-up and regulatory approval. In the near future, nanoshuttles will diversify in the fields of energy conversion, energy storage, 3D printing, stem cell fabrication and theranostics.

Applications of nanoscale metal-organic frameworks as imaging agents in biology and medicine

Nanoscale metal-organic frameworks (NMOFs) are an interesting and unique class of hybrid porous materials constructed by the self-assembly of metal ions/clusters with organic linkers. The high storage capacities, facile synthesis, easy surface functionalization, diverse compositions and excellent biocompatibilities of NMOFs have made them promising agents for theranostic applications. By combination of a large variety of metal ions and organic ligands, and incorporation of desired molecular functionalities including imaging modalities and therapeutic molecules, diverse MOF structures with versatile functionalities can be obtained and utilized in biomedical imaging and drug delivery. In recent years, NMOFs have attracted great interest as imaging agents in optical imaging (OI), magnetic resonance imaging (MRI), computed tomography (CT), positron emission tomography (PET) and photoacoustic imaging (PAI). Furthermore, the significant porosity of MOFs allows them to be loaded with multiple imaging agents and therapeutics simultaneously and applied for multimodal imaging and therapy as a single entity. In this review, which is intended as an introduction to the use of MOFs in biomedical imaging for a reader entering the subject, we summarize the up-to-date progress of NMOFs as bioimaging agents, giving (i) a broad perspective of the varying imaging techniques that MOFs can enable, (ii) the different routes to manufacturing functionalised MOF nanoparticles and hybrids, and (iii) the integration of imaging with differing therapeutic techniques. The current challenges and perspectives of NMOFs for their further clinical translation are also highlighted and discussed.