Nanostructured metal–organic frameworks and their bio-related applications

Competitive electrochemical immunosensor for maduramicin detection by multiple signal amplification strategy via hemin@Fe-MIL-88NH2/AuPt

Maduramicin (MD) is a type of monoglycoside polyether ionophore antibiotic that can effectively treat coccidiosis and facilitate animal growth. However, its extensive and excessive use brings potential risk to human health. Herein, an electrochemical immunosensor based on indirect competitive format was fabricated for analysis of MD residue in eggs by a multiple signal amplification system. Initially, Au nanoparticles were deposited onto glassy carbon electrode surface to load the coating antigen MD-BSA and to improve conductivity. Then the signal amplification platform was constructed by encapsulating hemin into Fe-MIL-88 NH₂ metal-organic frameworks (hemin@MOFs), and then the obtained composites were decorated with AuPt nanoparticles. The synthesized hemin@MOFs/AuPt was not only used as a signal amplification mediator, but also utilized as a carrier for immobilization of horseradish peroxidase-conjugated affinipure goat anti-mouse antibody (Ab₂-HRP) and horseradish peroxidase (HRP). The constructed hemin@MOFs/AuPt-Ab₂-HRP bioconjugates could effectively amplify the current signal since hemin@MOFs, AuPt and HRP all exhibited high catalytic activity towards the hydrogen peroxide. Moreover, the established immunosensor showed high sensitivity and stability during the detection procedure. With the synergistic catalytic effect of hemin@MOFs, AuPt and HRP, a wide detection range of 0.1-50 ng mL^-1 and a low detection limit of 0.045 ng mL^-1 were achieved (S/N = 3), respectively. Ultimately, the developed method displayed excellent performance in practical applications, providing a promising probability to detect other veterinary drug residues to guarantee food safety.

One pot synthesis of α-amylase metal organic framework (MOF)-sponge via dip-coating technique

Enzyme embedded metal-organic frameworks (MOFs) are blooming in the field of enzyme immobilization on account of their superior catalytic efficiency, thermal and chemical stability as compared to native enzyme. However, the separation and recovery of enzyme embedded MOF composite is quite challenging due to its nanometer size, high dispersity and low density which limits the reusability. In this work, α-amylase embedded zeolite imidazole framework (ZIF)-67 was fabricated onto melamine sponge using surfactant assisted dip coating technique. This was achieved in single pot making the method facile and rapid. α-Amylase MOF-sponge was analysed and characterized by FT-IR, XRD, SEM and TGA. We demonstrated that the encapsulation could maintain the active conformational structure of α-amylase after immobilization procedure with excellent bioactivity. Further, apart from merits of framework shielding, it offers mass transfer limitation for macromolecular substrate (like starch) which was determined and expressed as effectiveness factor (η) by using Michaelis-Menten enzyme kinetics. At the end, recycling studies were carried out for α-amylase MOF-sponge which showed 32% residual activity after six consecutive cycles. It is believed that this strategy has great potential in the field of continuous biotransformation (catalysis), biosensing and biomedicine application.

Ti-Based nanoMOF as an Efficient Oral Therapeutic Agent

Despite the interest in (Zn, Fe, and Zr)-nanoscaled metal-organic frameworks (nanoMOFs) as intravenous drug nanocarriers, their most convenient oral administration has been almost unexplored. In this scenario, an uncharted Ti-nanoMOF is originally proposed here as an oral therapeutic agent, not as a drug delivery system but as an innovative and efficient oral detoxifying agent of the challenge and timeliness salicylate intoxication (e.g., aspirin). Thus, this orally robust and biosafe Ti-nanoMOF is the only porous nanomaterial, among the six tested MOFs, able to adsorb and retain aspirin under the whole gastrointestinal tract, overpassing the capabilities of the current treatment (i.e., activated charcoal). Further, the biodistribution and bioremoval of Ti-nanoMOF have been assessed, proving a bioprotective character with an intact and almost complete removal by feces.

Homochiral BINAPDA-Zr-MOF for Heterogeneous Asymmetric Cyanosilylation of Aldehydes

A new homochiral BINAPDA-Zr-MOF was prepared by a new chiral organic linker of (R)-4,4'-(6,6'-dichloro-2,2'-diethoxyl-[1,1'-binaphthalene]-4,4'-diyl)dibenzoic acid (R-L) and ZrCl₄ under solvothermal conditions. Its structure was determined by Pawley refinement on the basis of the measured PXRD pattern determined for BINAPDA-Zr-MOF, and it showed that the obtained chiral MOF crystallized in the F2₃ space group with the same topological structure as that of UiO-66. The obtained BINAPDA-Zr-MOF can be a very active catalyst to catalyze aldehyde cyanosilylation. In addition, the chiral BINAPDA-Zr-MOF was a typical solid catalyst, which was proved by a hot leaching test; moreover, it could be reused at least five times without loss of its catalytic activity and enantioselectivity.

Sequential and recyclable sensing of Fe3+ and ascorbic acid in water with a terbium(iii)-based metal-organic framework

A water-stable three-dimensional (3D) metal-organic framework (MOF) of {[Tb(Cmdcp)(H₂O)₃]₂(NO₃)₂·5H₂O}_n (1, H₃CmdcpBr = N-carboxymethyl-(3,5-dicarboxyl)pyridinium bromide) has been synthesized and characterized. MOF 1 is highly emissive, giving rise to green luminescence that can be quenched by Fe³⁺ due to the partial overlap of its excitation spectrum with the absorption spectrum of Fe³⁺. The subsequent introduction of ascorbic acid (AA) leads to the reduction of Fe³⁺ into Fe²⁺, accompanied by the near-entire recovery of MOF 1 emission. The density functional theory (DFT) calculation results support the proposed mechanism. Such a sensing cycle is further transferable to urine and serum samples with a satisfactory near-quantitative recovery, highlighting its good potential in biologically relevant applications.

Solvent Adaptive Dynamic Metal-Organic Soft Hybrid for Imaging and Biological Delivery

A solvent responsive dynamic nanoscale metal-organic framework (NMOF) [Zn(1 a)(H₂ O)₂ ] has been devised based on the self-assembly of Zn^II and asymmetric bola-amphiphilic oligo-(p-phenyleneethynylene) (OPE) dicarboxylate linker 1 a having dodecyl and triethyleneglycolmonomethylether (TEG, polar) side chains. In THF solvent, NMOF showed nanovesicular morphology (NMOF-1) with surface decorated dodecyl chains. In water and methanol, NMOF exhibited inverse-nanovesicle (NMOF-2) and nanoscroll (NMOF-3) morphology, respectively, with surface projected TEG chains. The pre-formed NMOFs also unveiled reversible solvent responsive transformation of different morphologies. The flexible NMOF showed cyan emission and no cytotoxicity, allowing live cell imaging. Cisplatin (14.4 wt %) and doxorubicin (4.1 wt %) were encapsulated in NMOF-1 by non-covalent interactions and, in vitro and in vivo drug release was studied. The drug loaded NMOFs exhibited micromolar cytotoxicity.

Preparation of amine functionalized g-C3N4@H/SMOF NCs with visible light photocatalytic characteristic for 4-nitrophenol degradation from aqueous solution

At ambience temperature, a facile and large-scale sonochemical synthesis route was used to synthesize graphitic carbon nitride@[Ti₄C₂₄H₃₉N₃O₂₉] metal-organic framework nanocomposites (g-C₃N₄-X@^YTi-MIL125-NH₂ NCs, where X and Y stood for the weight percentages of g - C₃N₄ and the synthesis method of Ti-MIL125-NH₂, respectively) having 2-Amino-1,4-benzenedicarboxylic acid (2-ATA) ligand with amine functional free groups. The obtained NCs were characterized by FT-IR, PXRD, FE-SEM, BET, UV-DRS, PL, EIS, and zeta potential. Moreover, g-C₃N₄-X@^YTi-MIL125-NH₂ capability to eliminate 4-nitrophenol (4-NP) contaminant from water via visible light illumination was explored. Our synthesized NCs under a facile, green ultrasonic technique (i.e. g-C₃N₄-30@^STi-MIL125-NH₂) had a higher percentage of degradation than those from hydrothermal technique (i.e. g-C₃N₄-30@^HTi-MIL125-NH₂) with degradation percentages of 75% and 57%, respectively, which resulted in effective mass transfer and separation of photo - generated charge carriers. Additionally, this higher percentage of degradation could be attributed to the larger surface area and unique morphology of the ultrasonically synthesized particles with higher homogeneity and better and non-agglomerated distribution. Furthermore, excellent reusability and stability were observed for g-C₃N₄-30@^STi-MIL125-NH₂. We also explored the role of some scavengers in the degradation procedures to investigate the effect of active species. The experimental results were used to describe the suggested mechanism capability for improved photocatalysis.

Amino modified metal-organic frameworks as pH-responsive nanoplatforms for safe delivery of camptothecin

MIL-100(Fe) and MIL-101(Fe) metal-organic frameworks (MOFs) are excellent vehicles for drug delivery systems (DDSs) due to their high biocompatibility and stability in physiological fluids, as well as their pore diameter in the mesoporous range. Although they are appropriate for the internal diffusion of 20-(S)-camptothecin (CPT), a strongly cytotoxic molecule with excellent antitumor activity, no stable delivery system has been proposed so far for this drug based in MOFs. We here present novel DDSs based in amine functionalized MIL-100(Fe) and MIL-101(Fe) nanoMOFs with covalently bonded CPT. These CPT nanoplatforms are able to incorporate almost 20% of this molecule and show high stability at physiological pH, with no non-specific release. Based on their surface charge, some of these CPT loaded nanoMOFs present improved cell internalization in in vitro experiments. Moreover, a strong response to acid pH is observed, with up to four fold drug discharge at pH 5, which boost intracellular release by endosomolytic activity. These novel DDSs will help to achieve safe delivery of the very cytotoxic CPT, allowing to reduce the therapeutic dose and minimizing drug secondary effects.

Nanoscale Metal-Organic Frameworks for Phototherapy of Cancer

Phototherapy involves the irradiation of tissues with light, and is commonly implemented in the forms of photodynamic therapy (PDT) and photothermal therapy (PTT). Photosensitizers (PSs) are often needed to improve the efficacy and selectivity of phototherapy via enhanced singlet oxygen generation in PDT and photothermal responses in PTT. In both cases, efficient and selective delivery of PSs to the diseased tissues is of paramount importance. Nanoscale metal-organic frameworks (nMOFs), a new class of hybrid materials built from metal connecting points and bridging ligands, have been examined as nanocarriers for drug delivery due to their compositional and structural tunability, highly porous structures, and good biocompatibility. This review summarizes recent advances on using nMOFs as nanoparticle PSs for applications in PDT and PTT.

Ratiometric Monitoring of Thorium Contamination in Natural Water Using a Dual-Emission Luminescent Europium Organic Framework

Traditional analytical methods of thorium contamination suffer from several disadvantages such as time-consuming procedures and an equipment-intensive nature, leading to substantial challenges in rapid and on-site monitoring of thorium concentrations in complex natural water systems. We report here the first case of a luminescent metal organic framework based probe (ThP-1) for highly sensitive and selective self-calibrated sensing of Th⁴⁺ contamination in natural fresh water media with a notably facilitated detection procedure. The detection limit of ThP-1 was determined to be 24.2 μg/L, much lower than the thorium contamination standard of 246 μg/L in drinking water defined by the World Health Organization. Importantly, the detection procedure based on the rarely reported self-calibration manner is greatly beneficial in improving the detection accuracy. The self-calibrated luminescence evolution process shows a great anti-interference ability capable of detecting thorium contamination in a wide concentration range from 24.2 μg/L to 300 mg/L, which can not be achieved directly by the traditional methods. The Th⁴⁺-selective luminescence response originates from the selective uptake and efficient enrichment of Th⁴⁺ by the host framework of ThP-1 through inner-sphere coordination, which is further confirmed by batch experiments, X-ray absorption spectroscopic study, and DFT calculations.

Tuning the net topology of a ternary Ag(i)-1,2,4,5-tetra(4-pyridyl)benzene-carboxylate framework: structures and photoluminescence

Changing of auxiliary ligands leads to the formation of 1D–3D coordination structures and the use of dye molecules provides a way to promote the luminescence properties of MOFs.

Bio-related applications of porous organic frameworks (POFs)

Porous organic frameworks (POFs) are promising candidates for bio-related applications. This review highlights the recent progress in POF-based bioapplications, including drug delivery, bioimaging, biosensing, therapeutics, and artificial shells. These encouraging performances suggest that POFs used for bioapplications deserve more attention in the future.

Co(ii)-cluster-based metal–organic frameworks as efficient heterogeneous catalysts for selective oxidation of arylalkanes

Three Co-cluster-based metal–organic frameworks were designed and their catalytic activities for the selective oxidation of arylalkanes were explored.

Selective adsorption and removal of drug contaminants by using an extremely stable Cu(II)-based 3D metal-organic framework

The adsorption capacity of three representative pharmaceutical drugs and personal care products (PPCPs) viz. diclofenac sodium (DCF), chlorpromazine hydrochloride (CLF) and amodiaquin dihydrochloride (ADQ), were preliminarily studied using a water-stable Cu(II)-based metal organic framework (MOF) [Cu(BTTA)]_n·2DMF (1) (H₂BTTA = 1,4-bis(triazol-1-yl)terephthalic acid). We also investigated the factors influencing the adsorption such as concentration, pH, contact time, temperature and dosages. The results show that the adsorption capacity of 1 for DCF (650 mg g-¹) from aqueous medium, which is higher in comparison to most of the reported MOFs. While the adsorption of CLF and ADQ are only 67 mg g-¹ and 72 mg g-¹, respectively. The adsorption isotherm and adsorption kinetics indicated that the adsorption of diclofenac sodium by 1 follows Freundlich model with R² value of 0.9902 and pseudo-first-order kinetics with correlation coefficient 0.9939 and K₁ value of 0.0058 min^-1, respectively. Investigations indicate that 1 could become a potential material to adsorb DCF from aqueous medium.

Direct grafting-from of PEDOT from a photoreactive Zr-based MOF – a novel route to electrically conductive composite materials

Photochemical modification of Zr-bzpdc-MOF with PEDOT through direct polymerization of EDOT at the MOF surface gives an electrically conductive material.

A Biocompatible GdIII–Organic Framework Incorporating Polar Pores for pH-Sensitive Anti-Cancer Drug Delivery and Inhibiting Human Bone Tumour Cells

With the aim of developing new and effective drug delivery systems for cancer treatments, great effort has been devoted to the field of porous metal–organic framework (MOF) platforms because of their controlled drug release performance, high drug loading, and acceptable biocompatibility. In this contribution, we report a MOF [Gd2(H2O)3(SDBA)3](DMA)3] (1, DMA=N,N-dimethylacetamide) with open O donor sites functionalised 1D pores, which has been fabricated using a bent polycarboxylic acid organic linker 4,4′-sulfonyldibenzoic acid (H2SDBA) under solvothermal conditions. Single crystal X-ray diffraction (SCRD), thermogravimetric analysis (TGA), elemental analysis, X-ray powder diffraction (XPRD), and Brunauer–Emmett–Teller (BET) analysis were used to characterise the as-prepared complex 1. 5-Fluorouracil (5-Fu) loaded 1 was soaked in phosphate buffer saline (PBS) and the invitro drug release performance was monitored by HPLC analysis under different pH conditions. At the pH values of 7.4 and 6.5, different profiles of pH-responsive release were achieved, indicating that the drug release performance of 5-Fu loaded 1 is pH sensitive. Grand Canonical Monte Carlo (GCMC) simulation results demonstrate that the open O donor sites in the framework of 1 account for the slower drug release rate. The prepared carrier is found to be bio-compatible with MG63 cells (cancerous tissue) and oral epidermal cells (normal tissue), when tested by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The 5-Fu loaded carrier also shows a promising growth inhibition effect towards the human bone tumour cells MG63.

Degradation of ZIF-8 in phosphate buffered saline media

Understanding the stability of zeolitic imidazolate framework-8 (ZIF-8) under physiological conditions is critical in biotechnology and biomedicine for biosensing, biocatalysis, and drug delivery.

Immobilization of amidase into a magnetic hierarchically porous metal–organic framework for efficient biocatalysis

A novel core–shell magnetic hierarchically porous MOF has been designed and used for amidase immobilization, which demonstrated excellent catalytic performance.

Cyclodextrin-Based Metal-Organic Frameworks (CD-MOFs) in Pharmaceutics and Biomedicine

Metal-organic frameworks (MOFs) show promising application in biomedicine and pharmaceutics owing to their extraordinarily high surface area, tunable pore size, and adjustable internal surface properties. However, MOFs are prepared from non-renewable or toxic materials, which limit their real-world applications. Cyclodextrins (CDs) are a typical natural and biodegradable cyclic oligosaccharide and are primarily used to enhance the aqueous solubility, safety, and bioavailability of drugs by virtue of its low toxicity and highly flexible structure, offering a peculiar ability to form CD/drug inclusions. A sophisticated strategy where CD is deployed as a ligand to form an assembly of cyclodextrin-based MOFs (CD-MOFs) may overcome real-world application drawbacks of MOFs. CD-MOFs incorporate the porous features of MOFs and the encapsulation capability of CD for drug molecules, leading to outstanding properties when compared with traditional hybrid materials. This review focuses on the inclusion technology and drug delivery properties associated with CD-MOFs. In addition, synthetic strategies and currently developed uses of CD-MOFs are highlighted as well. Also, perspectives and future challenges in this rapidly developing research area are discussed.

A robust zirconium amino acid metal-organic framework for proton conduction

Proton conductive materials are of significant importance and highly desired for clean energy-related applications. Discovery of practical metal-organic frameworks (MOFs) with high proton conduction remains a challenge due to the use of toxic chemicals, inconvenient ligand preparation and complication of production at scale for the state-of-the-art candidates. Herein, we report a zirconium-MOF, MIP-202(Zr), constructed from natural α-amino acid showing a high and steady proton conductivity of 0.011 S cm^-1 at 363 K and under 95% relative humidity. This MOF features a cost-effective, green and scalable preparation with a very high space-time yield above 7000 kg m^-3 day^-1. It exhibits a good chemical stability under various conditions, including solutions of wide pH range and boiling water. Finally, a comprehensive molecular simulation was carried out to shed light on the proton conduction mechanism. All together these features make MIP-202(Zr) one of the most promising candidates to approach the commercial benchmark Nafion.

Derivative of Epigallocatechin-3-gallatea Encapsulated in ZIF-8 with Polyethylene Glycol-Folic Acid Modification for Target and pH-Responsive Drug Release in Anticancer Research

Epigallocatechin-3-gallatea (EGCG), a key component of tea, has been found to have anticancer activity but poor stability. To improve its antioxidative stability and widen the application of EGCG in anticancer therapy, a kind of EGCG derivative, EGCG palmitate (PEGCG), was synthesized and encapsulated in ZIF-8 nanoparticles with functionalization of folic acid (FA), which is commonly used as pH-responsive drug carrier. PEGCG encapsulated in polyethylene glycol (PEG)-FA/ZIF-8 nanoparticles (PEG-FA/PEGCG@ZIF-8 NPs) exhibits sixfold improvement of stability compared to that of free PEGCG. With target recognition between folic acid (FA) on the surface of NPs and overexpressed FA receptor (FR) in cancer cells, the NPs can be efficiently internalized into cells and present targeted effects of inhibition growth on HeLa cells (cancer cells) compared with HEK 293 cells (normal cells), consistent with the regulation of reactive oxygen species (ROS) level and the induction of autophagy. The detection of autophagy flux and the measurement of autophagy marked proteins in cells suggest that autophagy flux and the autophagosome formation are appreciably induced when the cells were treated with PEG-FA/PEGCG@ZIF-8 NPs. It indicates that pH-responsive PEG-FA/PEGCG@ZIF-8 NPs with target identification for cancer cells can be used as highly efficient drug carriers in targeting cancer chemotherapy.

Novel Surfaces in Extracorporeal Membrane Oxygenation Circuits

The balance between systemic anticoagulation and clotting is challenging. In normal hemostasis, the endothelium regulates the balance between anticoagulant and prothrombotic systems. It becomes particularly more challenging to maintain this physiologic hemostasis when we are faced with extracorporeal life support therapies, where blood is continuously in contact with a foreign extracorporeal circuit surface predisposing a prothrombotic state. The blood-surface interaction during extracorporeal life support therapies requires the use of systemic anticoagulation to decrease the risk of clotting. Unfractionated heparin is the most common anticoagulant agent widely used in this setting. New trends include the use of direct thrombin inhibitor agents for systemic anticoagulation; and surface modifications that aim to overcome the blood-biomaterial surface interaction by modifying the hydrophilicity or hydrophobicity of the polymer surface; and coating the circuit with substances that will mimic the endothelium or anti-thrombotic agents. To improve hemocompatibility in an extracorporeal circuit, replication of the anti-thrombotic and anti-inflammatory properties of the endothelium is ideal. Surface modifications can be classified into three major groups: biomimetic surfaces (heparin, nitric oxide, and direct thrombin inhibitors); biopassive surfaces [phosphorylcholine, albumin, and poly- 2-methoxyethylacrylate]; and endothelialization of blood contacting surface. The focus of this paper will be to review both present and future novel surface modifications that can obviate the need for systemic anticoagulation during extracorporeal life support therapies.

Multifunctional Supramolecular Materials Constructed from Polypyrrole@UiO-66 Nanohybrids and Pillararene Nanovalves for Targeted Chemophotothermal Therapy

Multifunctional supramolecular nanomaterials capable of targeted and multimodal therapy hold great potential to improve the efficiency of cancer therapeutics. Herein, we report a proof-of-concept nanoplatform for effective chemophotothermal therapy via the integration of folic acid-based active targeting and supramolecular nanovalves-based passive targeting. Inspired by facile surface engineering and designable layer-by-layer assembly concept, we design and synthesize PPy@UiO-66@WP6@PEI-Fa nanoparticles (PUWPFa NPs) to achieve efficient synergistic chemophotothermal therapy, taking advantage of the desirable photothermal conversion capability of polypyrrole nanoparticles (PPy NPs) and high drug-loading capacity of hybrid scaffolds. Significantly, pillararene-based pseudorotaxanes as pH/temperature dual-responsive nanovalves allow targeted drug delivery in pathological environment with sustained release over 4 days, which is complementary to photothermal therapy, and folic acid-conjugated polyethyleneimine (PEI-Fa) at the outmost layer through electrostatic interactions is able to enhance tumor-targeting and therapeutic efficiency. Such PUWPFa NPs showed efficient synergistic chemophotothermal therapy of cervical cancer both in vitro and in vivo. The present strategy offers not only the distinctly targeted drug delivery and release, but also excellent tumor inhibition efficacy of simultaneous chemophotothermal therapy, opening a new avenue for effective cancer treatment.

Metal-organic frameworks induce autophagy in mouse embryonic fibroblast cells

Autophagy is the lysosomal-dependent degradation process of intracellular substances in adaptation to environmental or developmental changes. It plays an essential role in maintaining cellular homeostasis while its dysfunction is involved in various human diseases. The regulation of autophagy has attracted more and more attention with the promise for improving treatment of diseases as a potential therapeutic target. Metal-organic frameworks (MOFs), as emerging biomaterials, have been investigated in the biological and biomedical fields in recent years. Therefore, it is interesting and significant to study the effects of MOFs on living cells from safety aspects as well as the therapeutic viewpoint, especially their effects on autophagy which have not been reported yet. In this study, the effects of Fe-MIL-101_NH2 on mouse embryonic fibroblasts (MEFs) were investigated and the potential applications of these nanoparticles in the regulation of autophagy were explored. Our results demonstrated that Fe-MIL-101_NH2 induced cytoprotective autophagy in MEFs instead of cytotoxicity. The activation of autophagy kept reactive oxygen species from accumulating, which protected MEFs from apoptosis. Further exploration of the possible mechanisms of MOF-induced autophagy revealed that the inhibition of mTOR pathway as well as the enhancement of Becline1 and Atg5 contributed to autophagy induction. Our study uncovered the autophagic effects and mechanistic insights of MOFs, which will be beneficial and meaningful to the safety evaluation and the reasonable and effective usage of MOFs.

GraftFast Surface Engineering to Improve MOF Nanoparticles Furtiveness

Controlling the outer surface of nanometric metal-organic frameworks (nanoMOFs) and further understanding the in vivo effect of the coated material are crucial for the convenient biomedical applications of MOFs. However, in most studies, the surface modification protocol is often associated with significant toxicity and/or lack of selectivity. As an alternative, how the highly selective and general grafting GraftFast method leads, through a green and simple process, to the successful attachment of multifunctional biopolymers (polyethylene glycol (PEG) and hyaluronic acid) on the external surface of nanoMOFs is reported. In particular, effectively PEGylated iron trimesate MIL-100(Fe) nanoparticles (NPs) exhibit suitable grafting stability and superior chemical and colloidal stability in different biofluids, while conserving full porosity and allowing the adsorption of bioactive molecules (cosmetic and antitumor agents). Furthermore, the nature of the MOF-PEG interaction is deeply investigated using high-resolution soft X-ray spectroscopy. Finally, a cell penetration study using the radio-labeled antitumor agent gemcitabine monophosphate (³ H-GMP)-loaded MIL-100(Fe)@PEG NPs shows reduced macrophage phagocytosis, confirming a significant in vitro PEG furtiveness.

Metal-organic framework nanoparticles for arsenic trioxide drug delivery

Arsenic trioxide is a double-edged sword: On the one hand it is known as a poison, on the other hand it is used as an anticancer drug. Though effective in the treatment of leukaemia, arsenic trioxide has not been able to be introduced into the treatment of solid tumour entities yet due to its dose-limiting toxicity. However, different in vitro and in vivo studies revealed arsenic trioxide to be a potent agent against different solid tumour entities, including atypical teratoid rhabdoid tumours (ATRT), a paediatric brain tumour entity with a very poor prognosis. To improve the pharmacokinetics and therapeutic efficacy of arsenic trioxide and to reduce its toxic side effects, we propose to use a metal-organic framework (MOF) as a drug carrier material. Herein we report on using a MOF called MFU-4l (Metal-Organic Framework Ulm University), consisting of Zn(ii) ions and bis(1H-1,2,3-triazolo[4,5-b],[4',5'-i])dibenzo[1,4]dioxin ligands, to deliver arsenic trioxide in a form of dihydrogen arsenite anions. The H₂AsO₃ ^- anions were introduced to the MOF in a nanoparticle formulation via a postsynthetic side ligand exchange. The prepared material was characterised by IR, TGA, XRPD, SEM-EDX, TEM, DLS, ICP-OES and adsorption analysis. The drug release studies at different pH values were carried out as well as cytotoxicity tests with different ATRT cell lines and non-tumorous-control cell lines. The MOF-based material was shown to be a promising candidate for arsenic trioxide drug delivery.

Coordination Modulation Method To Prepare New Metal-Organic Framework-Based CO-Releasing Materials

Aluminum-based metal-organic frameworks (MOFs), [Al(OH)(SDC)] _n, (H₂SDC: 4,4'-stilbenedicarboxylic acid), also known as CYCU-3, were prepared by means of the coordination modulation method to produce materials with different crystal size and morphology. In particular, we screened several reagent concentrations (20-60 mM) and modulator/ligand ratios (0-50), leading to 20 CYCU x_ y materials ( x: reagent concentration, y = modulator/ligand ratio) with different particle size and morphology. Noteworthy, the use of high modulator/ligand ratio gives rise to a new phase of CYCU-3 (CYCU-3' x_50 series), which was structurally analyzed. Afterward, to test the potential of these materials as CO-prodrug carriers, we selected three of them to adsorb the photo- and bioactive CO-releasing molecule (CORM) ALF794 [Mo(CNCMe₂CO₂H)₃(CO)₃] (CNCMe₂CO₂H = 2-isocyano-2-methyl propionic acid): (i) CYCU-3 20_0, particles in the nanometric range; (ii) CYCU-3 50_5, bar-type particles with heterogeneous size, and (iii) CYCU-3' 50_50, a new phase analogous to pristine CYCU-3. The corresponding hybrid materials were fully characterized, revealing that CYCU-3 20_0 with the smallest particle size was not stable under the drug loading conditions. Regarding the other two materials, similar ALF794 loadings were found (0.20 and 0.19 CORM/MOF molar ratios for ALF794@CYCU-3 50_5 and ALF794@CYCU-3' 50_50, respectively). In addition, these hybrid systems behave as CO-releasing materials (CORMAs), retaining the photoactive properties of the pristine CORM in both phosphate saline solution and solid state. Finally, the metal leaching studies in solution confirmed that ALF794@CYCU-3' 50_50 shows a good retention capacity toward the potentially toxic molybdenum fragments (75% of retention after 72 h), which is the lowest value reported for a MOF-based CORMA to date.