Study Of Metal-organic Frameworks Research Articles

Study of metal organic framework with siRNA for overcoming matrix barrierin breast cancer

Objective: This study aimed to develop a new delivery strategy that utilized metal organic framework (MOF) loaded with small-interfering RNA (siRNA) targeting ITGAV to overcome tumor matrix barrier, and thus enhance drug penetration and immune accessibility in breast cancer. Methods: MOF@siITGAV particles were constructed and characterized. The uptake of MOF@siITGAV in breast cancer cell line 4T1 was observed by the cellular uptake assay. The toxicity of MOF@siITGAV was detected by cell counting kit 8 (CCK-8). The blank control group, naked siITGAV group and MOF@siITGAV group were set. Real-time fluorescent quantitative polymerase chain reaction (RT-qPCR) and Western blot were used to detect the expressions of ITGAV. The level of transforming growth factor β1 (TGF-β1) in the cell culture medium was detected by enzyme-linked immunosorbent assay (ELISA). The penetration of MOF@siITGAV in 4T1 cells was tested by constructing 3D spheroids. Mouse models of triple negative breast cancer were established. The effect of MOF@siITGAV on the growth of transplanted tumors and main organs was verified. Imminohistochemical (IHC) was used to test the expression of collagen and CD8. Results: MOF@siITGAV particles were constructed with sizes of (198.0±3.3) nm and zeta potential of -(20.2±0.4) mV. MOF@siITGAV could be engulfed by 4T1 cells and triggered to release siRNA. Compared to the blank control group, the expression of ITGAV in the MOF@siITGAV group [(46.5±11.3)%] and the naked siITGAV group [(109.9±19.0)%] was lower. TGF-β1 in the cell culture medium of the blank control group, naked siITGAV group, and MOF@siITGAV group was (474.5±34.4) pg/ml, (437.2±16.5) pg/ml, and (388.4±14.4) pg/ml, respectively. MOF@siITGAV could better penetrate into 4T1 spheroids and exhibit no obvious toxicity. The cell viability was (99.7±3.5)%, (98.2±5.2)%, (97.3±6.6)%, (92.1±8.1)%, and (92.4±4.1)%, respectively, after MOF@siITGAV treatment with the concentration of 0, 10, 20, 40, 80, and 160 μg/ml, respectively, for 24 h. The tumor growth in the MOF@siITGAV group was suppressed significantly. After 15-day treatment, the tumor volume of the MOF@siITGAV group was (135.3±41.9) mm3, smaller than that of the blank control group [(691.1±193.0) mm3] (P=0.025). The expression of collagen and the number of CD8 positive cells of the MOF@siITGAV group were lower than those of the other two groups. No significant abnormalities were observed in the main organs of mice. Conclusions: Targeting the integrinαv on the surface of cancer cells could destroy extracellular matrix, improve drug delivery, and increase immune infiltration.

Recent advances in small-angle scattering techniques for MOF colloidal materials

This paper reviews the recent progress of small angle scattering (SAS) techniques, mainly including X-ray small angle scattering technique (SAXS) and neutron small angle scattering (SANS) technique, in the study of metal-organic framework (MOF) colloidal materials (CMOFs). First, we introduce the application research of SAXS technique in pristine MOFs materials, and review the studies on synthesis mechanism of MOF materials, the pore structures and fractal characteristics, as well as the spatial distribution and morphological evolution of foreign molecules in MOF composites and MOF-derived materials. Then, the applications of SANS technique in MOFs are summarized, with emphasis on SANS data processing method, structure modeling and quantitative structural information extraction. Finally, the characteristics and developments of SAS techniques are commented and prospected. It can be found that most studies on MOF materials with SAS techniques focus mainly on nanoporous structure characterization and the evolution of pore structures, or the spatial distribution of other foreign molecules loaded in MOFs. Indeed, SAS techniques take an irreplaceable role in revealing the structure and evolution of nanopores in CMOFs. We expect that this paper will help to understand the research status of SAS techniques on MOF materials and better to apply SAS techniques to conduct further research on MOF and related materials.

Advances in metal-organic frameworks for optically selective alkaline phosphatase activity monitoring: a perspective.

The study of Metal-Organic Frameworks (MOFs) has gained significant momentum due to their remarkable properties, including adjustable pore sizes, extensive surface area, and customizable compositions, which have urged scientists to investigate their applicability in pertinent societal issues such as water absorption, environmental remediation, and sensor technology. MOFs have the ability to transport and detect specific biomolecules, including proteins. One such biomolecule is alkaline phosphatase (ALP) that can be influenced by various diseases and can lead to severe consequences when its regulation is disrupted. The porous nature of MOFs and their tunable nature allows them to selectively adsorb, interact directly or indirectly with ALP. This ultimately influences the electronic and optical properties of the MOF, leading to measurable changes. Early detection and continuous monitoring of ALP play a crucial role in the use of an effective treatment, and recent studies have shown that MOFs are effective in detecting alkaline phosphatases. This manuscript offers a thorough examination of the potential biomedical applications of MOFs for monitoring alkaline phosphatase and envisions possible future trends in this field.

Advances in the study of metal-organic frameworks and their biomolecule composites for osteoporosis therapeutic applications.

With the population aging, osteoporosis (OP) is becoming more and more common, seriously affecting patients' quality of life and their families, and how to prevent and treat osteoporosis has become a hot topic. However, the current conventional method of treating OP is oral anti-osteoporosis medication, which has drawbacks such as first-pass elimination and gastrointestinal adverse effects. At the same time, osteoporosis can lead to microbial infections and the need to promote angiogenesis for bone healing, among other needs that often cannot be met with conventional treatments, and there is a risk of resistance to oral antibiotics for microbial infections. Metal-organic frameworks (MOFs) having a high specific surface area, high porosity, controlled degradation, and variable composition; they can not only be used as a carrier to control drug release, but can also play multiple roles in the treatment of OP and microbial infections by releasing metal ions, etc., so they have inherent advantages for OP, which is a disease that requires long-term treatment. Therefore, this paper reviews the research progress of MOFs and their biomacromolecular composites in therapeutic applications for osteoporosis, categorized by MOF type, and briefly describes the mechanism of osteoporosis, and different synthesis methods of MOFs and MOF-based composites, and finally presents the main existing problems and future perspectives, aiming to make MOFs more helpful for OP treatment.

Thermo-, Electro-, and Photocatalytic CO2 Conversion to Value-Added Products over Porous Metal/Covalent Organic Frameworks.

ConspectusThe continuing increase of the concentration of atmospheric CO2 has caused many environmental issues including climate change. Catalytic conversion of CO2 using thermochemical, electrochemical, and photochemical methods is a potential technique to decrease the CO2 concentration and simultaneously obtain value-added chemicals. Due to the high energy barrier of CO2 however, this method is still far from large-scale applications which requires high activity, selectivity, and stability. Therefore, development of efficient catalysts to convert CO2 to different products is urgent. With their well-engineered pores and chemical compositions, high surface area, elevated CO2 adsorption capability, and adjustable active sites, porous crystalline frameworks including metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) are potential materials for catalytic CO2 conversion. Here, we summarize our recent work on MOFs and COFs for thermocatalytic, electrocatalytic, and photocatalytic CO2 conversion and describe the structure-activity relationships that could guide the design of effective catalysts.The first section of this paper describes imidazolium-functionalized porous MOFs, including porous liquid and cationic MOFs with nucleophilic halogen ions, which can promote thermocatalytically CO2 cycloaddition reaction with epoxides toward cyclic carbonates at one bar pressure. A porous liquid MOF takes on the role of a CO2 reservoir to tackle the low local CO2 concentrations in gas-liquid-solid heterogeneous reactions. Imidazolium-functionalized MOFs with halogen ions for CO2 cycloaddition could avoid the use of cocatalysts, and this leads to milder and more facile experimental conditions and separation processes.In a section dealing with the electrocatalytic CO2 reduction reaction (CO2RR), we developed a series of conductive porous framework materials with fast electron transmission capabilities, which afford high current densities and outperform the traditional MOF and COF catalysts that have been reported. The intrinsically conductive two-dimensional 2D MOFs and COFs nanosheets based on the fully π-conjugated phthalocyanine motif with excellent electron transport capability were prepared, and strong electron transporters were also integrated into metalloporphyrin-based COFs for CO2RR. Cu2O quantum dots and Cu nanoparticles (NPs) can be uniformly dispersed on porous conductive MOFs/COFs to afford synergistic and/or tandem electrocatalysts, which can achieve highly selective production of CH4 or C2H4 in CO2RR.A third section describes our efforts to facilitate electron-hole separation in CO2 photocatalysis. Our focus is on regulation of coordination spheres in MOFs, fabrication of the architecture of MOF heterojunctions, and engineering MOF films to facilitate photocatalytic CO2 reduction.Finally, we discuss several problems associated with the studies of MOFs and COFs for CO2 conversion and consider some prospects of the fabrication of effective porous frameworks for CO2 adsorption and conversion.

Two new 3D lanthanide-organic frameworks based on rod-shaped metal-carboxylate chain SBU: Synthesis, characterization and luminescent detection of Fe3+ and S2− in aqueous solution

The study of metal-organic frameworks (MOFs) as luminescence sensors for the detection of polluting molecules and ions are of great importance to the health of all creatures in the world. In this research field, lanthanide ions, especially for Eu3+ and Tb3+, have intrinsic advantages based on their outstanding luminescent properties. To develop smart luminescence sensors towards heavy metal ions and acid anions, two new lanthanide(III)-based MOFs: {[Ln2(btpdc)3·DMF·2H2O]·2DMF·4H2O}n (Ln ​= ​Eu (1), Tb (2), H2btpdc ​= ​benzo[b]thiophene-2,6-dicarboxylic acid) were designed and synthesized under solvothermal condition based on a dicarboxylate ligand H2btpdc. Single crystal X-ray diffraction tests show the two complexes are isostructural with three dimensional (3D) porous framework structure. Notably, both of them exhibit good chemical stability in water. Under the excitation of ultra-violet light, 1 can exhibit strong Eu3+-based red light emission in both solid state and aqueous suspension while 2 doesn't show observable luminescence emission. The luminescence sensing experiments performed on 1 reveal that it can be employed as a smart “turn-off” luminescence sensor for the detection of Fe3+ or S2− in aqueous solution with high selectivity, low detection limit, good anti-interference ability and recyclability. The obtained quenching constant Ksv and detection limits are 2.316 ​× ​104 ​M−1 and 0.26 ​μM, respectively, for Fe3+, and 1.38 ​× ​104 ​M−1 and 1.05 ​μM, respectively, for S2−.

Theoretical Studies of Metal-Organic Frameworks: Calculation Methods and Applications in Catalysis, Gas Separation and Battery

Theoretical Studies of Metal-Organic Frameworks: Calculation Methods and Applications in Catalysis, Gas Separation and Battery

2D CoP supported 0D WO3 constructed S-scheme for efficient photocatalytic hydrogen evolution

For heterojunction composite photocatalyst, intimate contact interface is the key to the carrier transfer separation conditions. Due to the interface contact, the electron transfer rate between catalysts can be increased during photocatalytic hydrogen production, therefore, we design the close contact of 0D/2D heterojunction, which greatly enhanced the photocatalytic hydrogen production activity of the composite catalyst. The composite catalyst WO3/CoP was obtained by simple high temperature in situ synthesis. Moreover, it was proved by photoelectric chemistry and fluorescence tests that appropriate conduction band and valence band locations of WO3 and CoP provided a favorable way for thermodynamic electron transfer. In addition, fluorescence results showed that WO3 load effectively promoted photoelectron-hole transfer and increased electron lifetime. The formation of S-scheme heterojunctions can make more efficient use of useful photogenerated electrons and prevent the photogenerated electron-hole recombination of CoP itself, further promote the liveness of photocatalytic H2 evolution. Meanwhile, the study of Metal-organic frameworks (MOFs) materials further promoted the application of MOFs derivatives in the field of photocatalytic hydrogen evolution, and provided a reference for the rational design of composite catalysts for transition metal phosphide photocatalysts.

Four novel 3D RE-MOFs based on maleic hydrazide: Syntheses, structural diversity, efficient electromagnetic wave absorption and antibacterial activity properties

Maleic hydrazide (MH), a six-membered heterocycle, contains two rigid lactam groups. Although MH has more than one coordination site, structural information regarding its metal organic frameworks (MOFs), especially rare-earth metal organic frameworks (RE-MOFs), is barely reported. In this work, four novel RE-MOFs [Y2(MH)6]n·DMF (1), [Er2(MH)6]n (2), [Yb2(MH)6]n (3), and [La(MH)3]n (4) were successfully synthesized by hydrothermal reactions and characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental analyses, powder X-ray diffraction (PXRD) and thermogravimetric analyses (TGA). The organic linkers bind to the central metal ions through oxygen atoms in MOFs 1–3 (isostructural), and the organic linkers bind to the central ions through both oxygen atoms and nitrogen atoms in MOF 4. The electromagnetic wave absorption (EMWA) studies of MOFs 1–4 demonstrate that these MOFs with special porous structures have impressive EMWA performance. A maximum reflection loss (RL) value of −22.78 dB, with a broad effective absorption bandwidth of 2.24 GHz, can be obtained for MOF 1. Additionally, for MOF 2, a maximum RL value of −20 dB can be obtained. Both MOF 3 and MOF 4 have narrow effective EMWA bandwidths with maximum RL values of −28.14 dB and −13.07 dB. The excellent EMWA property may be attributed to the synergetic and complementary effects of permittivity and permeability. Additionally, MOFs 1–4 were tested for antibacterial activity. The results show that all the tested MOFs exhibit significant antibacterial properties. In particular, MOF 4 has the strongest antibacterial activity against two tested pathogenic bacteria compared to MOFs 1–3.

Molecular simulation study of metal organic frameworks for methane capture from low-concentration coal mine methane gas

Methane and nitrogen are the main components in the coal mine drainage gases. However, it is the most difficult to separate methane from CH4 to N2 mixtures due to the completely nonpolar molecule for these two components. Research on the adsorption and separation properties of CH4 and N2 may have great significance for methane purification from coal mine methane. In the present work, adsorption and separation performance of 22 different metal–organic frameworks (MOFs) for CH4, N2 and their binary mixtures at room temperature have been investigated using molecular simulation method. Results show that the adsorption capacity is mainly dominated by the occupied sites and small pore spaces for pure CH4 or N2 adsorption. Compared with N2, CH4 would be preferentially adsorbed in all MOFs, which is consistent with the rules of adsorption heat, especially at low pressure ranges. Methane uptake with low gas adsorption loadings is mainly controlled by the interactions between adsorbate and frameworks caused by small pore spaces. And, there is a linear rule between methane uptakes and surface areas or pore volumes. The adsorption isotherms of CH4/N2 binary mixtures could be well predicted based on single-component isotherms using IAST method. Analyses on CH4/N2 mixture adsorption selectivity show that MOFs are the promising candidate for methane capture from CH4/N2 mixtures. Among all the selected MOFs, ZIF-7 is the most promising porous material for CH4/N2 mixture separation. The parameter of adsorbility is showing well correlations with the selectivity of CH4/N2 mixture, which can be served as a general criterion for the preliminary screening of MOFs for methane separation applications.

Electronic structure modulation of metal-organic frameworks for hybrid devices.

The study of metal–organic frameworks has largely been motivated by their structural and chemical diversity; however, these materials also possess rich physics, including optical, electronic, and magnetic activity. If these materials are to be employed in devices, it is necessary to develop an understanding of their solid-state behavior. We report an approach to calculate the effect of strain on the band structure of porous frameworks. The origin of the bidirectional absolute deformation potentials can be described from perturbations of the organic and inorganic building blocks. The unified approach allows us to propose several uses for hybrid materials, beyond their traditionally posited applications, including gas sensing, photoelectrochemistry, and as hybrid transistors.

Understanding gas separation in metal–organic frameworks using computer modeling

Metal–organic frameworks (MOFs) are a new family of nanoporous materials that combine the advantages of both inorganic and organic materials with great variety in functionality, pore size and topology. Gas separation is one of the fields that the first practical application of MOFs may be applied to; however, the study of MOFs as adsorbents in gas separation is still in its early stage, and their separation characteristics are not quite clear. Here, we summarize the recent advances on gas separation in MOFs using computer modeling, and show how computer modeling can help to understand the separation characteristics of MOFs. In addition, several strategies are proposed to improve the separation efficiency of MOFs, which are expected to be useful for designing new MOFs with improved separation performance for targeted properties.