Metal-organic Framework Nanoparticles Research Articles

Electrostatic assembly of gold nanoparticle and metal-organic framework nanoparticles attenuates amyloid β aggregate-mediated neurotoxicity.

The deposition of amyloid β (Aβ) is a conventional pathological hallmark of Alzheimer's disease (AD). Consequently, the inhibition of Aβ aggregation combined with the disaggregation of Aβ fibrils is an important therapeutic method for AD treatment. In this study, a gold nanoparticle-decorated porous metal organic framework MIL-101(Fe) (AuNPs@PEG@MIL-101) was created as an Aβ inhibitor. The high positively charged MIL-101 induced a high number of Aβ40 to be absorbed or aggregated on the surface of nanoparticles. In addition, AuNPs improved the surface property of MIL-101, causing it to uniformly bind Aβ monomers and Aβ fibrils. Thus, this framework can efficiently suppress extracellular Aβ monomer fibrillation and disrupt the preformed Aβ fibers. AuNPs@PEG@MIL-101 also decreases intracellular Aβ40 aggregation and the amount of Aβ40 immobilized on the cell membrane, thus protecting PC12 cells from Aβ40-induced microtubular defects and cell membrane damage. In summary, AuNPs@PEG@MIL-101 shows great potential for application in AD therapy.

Effect of modulator ligands on the growth of Co2(dobdc) nanorods.

Control over the size, shape, uniformity, and external surface chemistry of metal-organic framework nanocrystals is important for a wide range of applications. Here, we investigate how monotopic modulators that mimic the coordination mode of native bridging ligands affect the growth of anisotropic Co2(dobdc) (dobdc4- = 2,5-dihydroxy-1,4-benzenedicarboxylic acid) nanorods. Through a combination of transmission electron microscopy (TEM) and nuclear magnetic resonance spectroscopy (NMR) studies, nanorod diameter was found to be strongly correlated to the acidity of the modulator and to the degree of modulator incorporation into the nanorod structure. Notably, highly acidic modulators allowed for the preparation of sub-10 nm nanorods, a previously elusive size regime for the M2(dobdc) family. More broadly, this study provides new insights into the mechanism of modulated growth of metal-organic framework nanoparticles.

Electrospun nanofibers of chitosan/polyvinyl alcohol/UiO-66/nanodiamond: Versatile adsorbents for wastewater remediation and organic dye removal

The appeal of metal–organic frameworks (MOFs) in wastewater treatment is tempered by their polycrystalline, powdery state, and challenges associated with their deployment. In the case of UiO-66, one of the most stable and widely-used MOFs, a low tendency for removing some organic contaminants has been observed on top of the mentioned issues. To address these challenges, herein, we take two complementary steps, i.e., hybridization of UiO-66 with organic nanodiamond (ND) followed by the integration of the hybrid nanoparticles in electrospun polymeric nanofibers based on chitosan/polyvinyl alcohol (PVA). We present the electrospinning of polymer/MOFs as a promising technique to fabricate highly efficient adsorbents for water remediation. We use the electrospun chitosan/PVA nanofibers (ECPN) as a versatile host for MOF nanoparticles that remove cationic methylene blue and anionic Congo red dyes. Four nanofiber composites containing thermally oxidized nanodiamond (TOND), ND, UiO-66, and TOND@UiO-66 are utilized to unravel the effect of nanoparticles type and loading on dye adsorption capacity. It is shown that incorporation of a small loading of nanoparticles in ECPN significantly enhaces the maximum dye adsorption capacity. More importantly, the rationally engineered hybrid TOND@UiO-66 nanoparticles exhibit the best performance in dye adsorption; for instance, an 80 % increase in maximum dye adsorption capacity, from 769 to 1429 mg/g, is recorded for ECPN loaded with TOND@UiO-66 compared to the unfilled ECPN. On top of that, the designed adsorbent showed appreciable regeneration ability after 6 adsorption–desorption cycles. All in all, this study offers a new generation of engineered advanced materials to remove emerging contaminants from water streams.

PD‐L1 Aptamer‐Functionalized Metal–Organic Framework Nanoparticles for Robust Photo‐Immunotherapy against Cancer with Enhanced Safety

AbstractImmune checkpoint blockade has become a paradigm‐shifting treatment modality to combat cancer, while conventional administration of immune checkpoint inhibitors, such as anti‐PD‐L1 antibody (α‐PD‐L1), often shows unsatisfactory immune responses and lead to severe immune‐related adverse effects (irAEs). Herein, we develop a PD‐L1 aptamer‐based spherical nucleic acids (SNAs), which consists of oxaliplatin (OXA) encapsulated in a metal–organic framework nanoparticle core and a dense shell of aptPD‐L1 (denoted as M@O‐A). Upon light irradiation, this nanosystem enables concurrent photodynamic therapy (PDT), chemotherapy, and enhanced immunotherapy in one shot to inhibit both primary colorectal tumors and untreated distant tumors in mice. Notably, M@O‐A shows scarcely any systemic immunotoxicity in a clinical irAEs‐mimic transgenic mouse model. Collectively, this study presents a novel strategy for priming robust photo‐immunotherapy against cancer with enhanced safety.

PD-L1 Aptamer-Functionalized Metal-Organic Framework Nanoparticles for Robust Photo-Immunotherapy against Cancer with Enhanced Safety.

Immune checkpoint blockade has become a paradigm-shifting treatment modality to combat cancer, while conventional administration of immune checkpoint inhibitors, such as anti-PD-L1 antibody (α-PD-L1), often shows unsatisfactory immune responses and lead to severe immune-related adverse effects (irAEs). Herein, we develop a PD-L1 aptamer-based spherical nucleic acids (SNAs), which consists of oxaliplatin (OXA) encapsulated in a metal-organic framework nanoparticle core and a dense shell of aptPD-L1 (denoted as M@O-A). Upon light irradiation, this nanosystem enables concurrent photodynamic therapy (PDT), chemotherapy, and enhanced immunotherapy in one shot to inhibit both primary colorectal tumors and untreated distant tumors in mice. Notably, M@O-A shows scarcely any systemic immunotoxicity in a clinical irAEs-mimic transgenic mouse model. Collectively, this study presents a novel strategy for priming robust photo-immunotherapy against cancer with enhanced safety.

A Lignin-Based Carbon Anode with Long-Cycle Stability for Li-Ion Batteries.

Due to its wide source and low cost, biomass-based hard carbon is considered a valuable anode for lithium-ion batteries (LIBs). Lignins, as the second most abundant source in nature, are being intensively studied as candidate anode materials for next generation LIBs. However, direct carbonization of pure lignin usually leads to low specific surface area and porosity. In this paper, we design a porous carbon material from natural lignin assisted by sacrificing a metal-organic framework (MOF) as the template. The MOF nanoparticles can disperse the lignin particles uniformly and form abundant mesopores in the composites to offer fast transfer channels for Li+. The as-prepared carbon anode shows a high specific capacity of 420 mAh g-1 with the capacity retention of 99% after 300 cycles at 0.2 A g-1. Additionally, it keeps the capacity retention of 85% after long cycle of 1000 cycles, indicating the good application value of the designed anode in LIBs. The work provides a renewable and low-cost candidate anode and a feasible design strategy of the anode materials for LIBs.

Metal-Organic Framework-DNA Bio-Barcodes Amplified CRISPR/Cas12a Assay for Ultrasensitive Detection of Protein Biomarkers.

CRISPR/Cas12a shows excellent potential in disease diagnostics. However, insensitive signal conversion strategies hindered its application in detecting protein biomarkers. Here, we report a metal-organic framework (MOF)-based DNA bio-barcode integrated with the CRISPR/Cas12a system for ultrasensitive detection of protein biomarkers. In this work, zirconium-based MOF nanoparticles were comodified with antibodies and bio-barcode phosphorylated DNA as an efficient signal converter, which not only recognized the protein biomarker to form the sandwich complex but also released the bio-barcode DNA activators after MOF dissociation to activate the trans-cleavage activity of Cas12a. Due to the obvious advantages, including numerous loaded oligonucleotides, a convenient release process, and the nontoxic release reagent, this MOF-DNA bio-barcode strategy could amplify the CRISPR/Cas12a system to achieve simple and highly sensitive detection of tumor protein biomarkers with detection limits of 0.03 pg/mL (PSA) and 0.1 pg/mL (CEA), respectively. Furthermore, this platform could detect PSA directly in clinical serum samples, offering a powerful tool for early disease diagnosis.

Microcurvature Controllable Metal-Organic Framework Nanoagents Capable of Ice-Lattice Matching for Cellular Cryopreservation.

Ice-binding proteins (IBPs) produced by psychrophilic organisms to adapt for the survival of psychrophiles in subzero conditions have received illustrious interest as a cryopreservation agent required for cells and tissues to completely recover after freezing/thawing. Depressing water-freezing point and avoiding ice-crystal growth affect their activities which are closely related to the presence of ice crystal well-matched binding moiety. The interaction of IBPs with ice and water is critical in enhancing their freeze avoidance against cell or tissue damage. Metal-organic frameworks (MOFs) with a controllable lattice at the molecular level and a size at the nanometer scale can offer periodically ordered ice-binding sites by modifying organic linkers and controlling microcurvature at the ice surface. Herein, zirconium (Zr)-based MOF-801 nanoparticles (NPs) with good biocompatibility were used as a cryoprotectant that is well dispersed and colloidal-stable in an aqueous solution. The MOF NP size was precisely controlled, and 10, 35, 100, and 250 nm NPs were prepared. The specific IBPs-mimicking pendants (valine and threonine) were simply introduced into the MOF NP-surface through the acrylate-based functionalization to endow with hydrophilic and hydrophobic dualities. When small-sized MOF-801 NPs were attached to ice, they confined ice growth in high curvature between the adsorption sites because of the decreased radius of the convex area of the growth region, leading to highly enhanced ice recrystallization inhibition (IRI). Surface-functionalized MOF NPs could increase the number of anchored clathrate water molecules with hydrophilic/hydrophobic balance of the ice-binding moiety, effectively inhibiting ice growth. The MOF-801 NPs were biocompatible with various cell lines regardless of concentration or NP surface-functionalization, whereas the smaller-sized surface-functionalized NPs showed a good cell recovery rate after freezing/thawing by induction of IRI. This study provides a strategy for the fabrication of low-cost, high-volume antifreeze nanoagents that can extend useful applications to organ transplantation, cord blood storage, and vaccines/drugs.

Reversing ferroptosis resistance by MOFs through regulation intracellular redox homeostasis

As a non-apoptotic cell death form, ferroptosis offers an alternative approach to overcome cancer chemotherapy resistance. However, accumulating evidence indicates cancer cells can develop ferroptosis resistance by evolving antioxidative defense mechanisms. To address this issue, we prepared a Buthionine-(S,R)-sulfoximine (BSO) loaded metal organic framework (MOF) of BSO-MOF-HA (BMH) with the combination effect of boosting oxidative damage and inhibiting antioxidative defense. MOF nanoparticle was constructed by the photosensitizer of [4,4,4,4-(porphine-5,10,15,20-tetrayl) tetrakis (benzoic acid)] (TCPP) and the metal ion of Zr6, which was further decorated with hyaluronic acid (HA) in order to impart active targeting to CD44 receptors overexpressed cancer cells. BMH exhibited a negative charge and spherical shape with average particle size about 162.5 nm. BMH was found to restore the susceptibility of 4T1 cells to ferroptosis under irradiation. This was attributed to the combination of photodynamic therapy (PDT) and γ-glutamylcysteine synthetase inhibitor of BSO, shifting the redox balance to oxidative stress. Enhanced ferroptosis also induced the release of damage associated molecular patterns (DAMPs) to maturate dendritic cells and activated T lymphocytes, leading to superior anti-tumor performance in vivo. Taken together, our findings demonstrated that boosting oxidative damage with photosensitizer serves as an effective strategy to reverse ferroptosis resistance.

Stimuli-responsive metal–organic framework hydrogels endow long carbon fiber reinforced polyetheretherketone with enhanced anti-inflammatory and angiogenesis and osteogenesis

The ideal orthopedic implant has sufficient biomechanical strength and physiological activity to coordinate with the intricate physiological healing process of the tissue. Herein, multifunctional stimuli-responsive metal–organic framework (MOF) hydrogels on the surface of the sulfonated long carbon fiber reinforced polyetheretherketone (LCFRPEEK) implant using the UV-grafting method is constructed to coordinate with the osseointegration process. The hydrogels are composed of nano-hydroxyapatite cored magnesium-gallic acid (HAP@Mg-GA) MOF nanoparticles and methacryloylchitosan. The stimuli-responsive MOF hydrogels exhibit outstanding pH-sensitive biomolecule release capabilities. The outcomes of in vitro cell experiments demonstrate that the multifunctional sulfonated LCFRPEEK could actively and precisely perform immunomodulation, timely scavenge excess ROS and reduce NO production under the immune environment (low pH), as well as promote angiogenesis and osteogenic differentiation benefiting from the cooperation of GA, Mg2+ and Ca2+. Furthermore, the in vivo SD rat subcutaneous implantation and rabbit tibia defect models further demonstrate that the implant has superior in vivo immunomodulation, angiogenesis, osteogenic differentiation, and osseointegration abilities. Therefore, the study provides a new multifunctional orthopedic implant that can achieve osseointegration, which broadens the effective application of LCFRPEEK biomaterials in orthopedics.

Metal-organic framework nanoparticles as a free radical scavenger improving the stability of epoxy under high dose gamma irradiation

Understanding the degradation mechanism of epoxy resin under irradiation and enhancing the radiation resistance of epoxy resin are of great significance for its application in aerospace and nuclear industries. In this study, we investigated the radiation resistance of epoxy reinforced by UIO-66-OH metal-organic framework. Outstanding radiation resistance was achieved by using UIO-66-OH nanoparticles as radical scavengers to retard epoxy degradation. The introduction of UIO-66-OH reduces the content of free radicals generated after irradiation by 88.17%. UIO-66-OH also improves the mechanical and thermal properties of epoxy before and after irradiation. The scavenging radicals mechanism of hydrogen atom transfer of UIO-66-OH is more dominant than that of graphene oxide and carbon nanotubes. The radiation resistance of UIO-66-OH nanoparticles is related to hydroxyl functionalization and porous structure. This work provides a new idea and method for improving the stability of epoxy resin under gamma ray radiation.

“Non-cytotoxic” doses of metal-organic framework nanoparticles increase endothelial permeability by inducing actin reorganization

Cytotoxicity of nanoparticles is routinely characterized by biochemical assays such as cell viability and membrane integrity assays. However, these approaches overlook cellular biophysical properties including changes in the actin cytoskeleton, cell stiffness, and cell morphology, particularly when cells are exposed to “non-cytotoxic” doses of nanoparticles. Zeolitic imidazolate framework-8 nanoparticles (ZIF-8 NPs), a member of metal–organic framework family, has received increasing interest in various fields such as environmental and biomedical sciences. ZIF-8 NPs may enter the blood circulation system after unintended oral and inhalational exposure or intended intravenous injection for diagnostic and therapeutic applications, yet the effect of ZIF-8 NPs on vascular endothelial cells is not well understood. Here, the biophysical impact of “non-cytotoxic” dose ZIF-8 NPs on human aortic endothelial cells (HAECs) is investigated. We demonstrate that “non-cytotoxic” doses of ZIF-8 NPs, pre-defined by a series of biochemical assays, can increase the endothelial permeability of HAEC monolayers by causing cell junction disruption and intercellular gap formation, which can be attributed to actin reorganization within adjacent HAECs. Nanomechanical atomic force microscopy and super resolution fluorescence microscopy further confirm that “non-cytotoxic” doses of ZIF-8 NPs change the actin structure and cell morphology of HAECs at the single cell level. Finally, the underlying mechanism of actin reorganization induced by the “non-cytotoxic” dose ZIF-8 NPs is elucidated. Together, this study indicates that the “non-cytotoxic” doses of ZIF-8 NPs, intentionally or unintentionally introduced into blood circulation, may still pose a threat to human health, considering increased endothelial permeability is essential to the progression of a variety of diseases. From a broad view of cytotoxicity evaluation, it is important to consider the biophysical properties of cells, since they can serve as novel and more sensitive markers to assess nanomaterial’s cytotoxicity.

A hydrogel-based biosensor for stable detection of glucose

Glucose detection is vital in the food industry for safety and quality management. As a healthy ingredient, the flavor of honey is frequently impacted by the crystallization of glucose. Therefore, determining the glucose level can offer precise reference data for the manufacture of honey. Various approaches have been tried, and the enzyme-based electrochemical analytical method is one of the most important and widely used strategies. However, there are still challenges for most electrochemical methods to achieve stable detection resistant to temperature variation due to the easy inactivation of the enzyme, the poor anti-interference capacity of the detection techniques and other influences from the external environment. Herein, a hydrogel-based electrochemical biosensor is proposed to stably detect glucose even at wide ranges of temperatures via electrochemical impedance spectroscopic (EIS) measurement. The key factor for stable detection relies on the metal-organic framework nanoparticles' protective layer to guarantee the robustness of glucose oxidase (GOx), thereby achieving stable and specific detection for glucose. Moreover, a cascade reaction-induced hydrogel formation in a 3D structure can be used as an impedance readout, which not only amplifies but also further stabilizes the GOx-induced response. The prepared hydrogel-based electrochemical biosensor showed a linear response to the glucose concentration in the range of 0.75–4 mg/mL. Furthermore, the biosensor has excellent anti-interference and temperature stability. High performance liquid chromatography analysis also validated the accuracy of this biosensor in detecting glucose in the honey sample.

In-situ etching MOF nanoparticles for constructing enhanced interface in hybrid membranes for gas separation

Metal-organic frameworks (MOFs) based hybrid membranes have great potential for energy-efficient gas separation. However, the defective interface structure greatly depresses their separation performance. In this work, a distinctive interfacial design strategy via in-situ etching ZIF-8 nanoparticles is proposed to construct hybrid membranes with nearly defect-free interfaces. The nanoscale etching of ZIF-8 nanoparticles in polymer matrix with acid group (PI-COOHx) is well controlled by the amount of carboxyl group and reaction time. Owing to the strong coordination interaction between Zn2+ ions and –COOH groups, the residual ZIF-8 nanoparticles are tightly wrapped by polymer matrix. Molecular simulation was performed to study the in-situ etching ZIF-8 in PI-COOHx matrix in molecular level. The resulted hybrid membranes (PI-COOHx/E-ZIF-8) exhibit simultaneously enhanced permeability and selectivity with increasing filler loading content. Benefiting from the rational interfacial design, the effective loading content of ZIF-8 nanoparticles is up to 50 wt% for PI-COOH20/E-ZIF-8 membrane. The H2, CO2, and O2 permeability of the membrane are 3058.6, 1429.0, and 459.0 Barrer, increasing by 468.5%, 288.3% and 348.2%, respectively, of pristine PI-COOH20 membrane, and the gas selectivity for H2/N2, H2/CH4, O2/N2, and CO2/CH4 gas pairs are greatly improved from 20.3, 23.4, 3.9 and 16.0 of pristine PI-COOH20 membrane to 30.7, 37.6, 4.6 and 17.6. The comprehensive separation performance for H2/N2, H2/CH4, and O2/N2 gas pairs surpass the 2008 upper bound and approach the 2015 upper bound. Meanwhile, the CO2 plasticization resistance of PI-COOH20/E-ZIF-8 membrane also achieves significant improvement from 6 bar of PI-COOH20 membrane to 27 bar. This work provides an effective and robust strategy to effectively enhance the interfacial compatibility of hybrid membranes.

Targeted OUM1/PTPRZ1 silencing and synergetic CDT/enhanced chemical therapy toward uveal melanoma based on a dual-modal imaging-guided manganese metal–organic framework nanoparticles

Metastasis and chemical resistance are the most serious problems in the treatment of highly aggressive uveal melanoma (UM). The newly identified lncRNA OUM1 is overexpressed in UM, functions as a catalyst and regulates protein tyrosine phosphatase (PTP) activity by binding to PTP receptor type Z1 (PTPRZ1), which plays an important role in cell proliferation, metastasis and chemotherapy resistance in the UM microenvironment. Hence, siRNAs that selectively knocking down the lncRNA OUM1 (siOUM1) and its target gene PTPRZ1 (siPTPRZ1) were designed to inhibit the OUM1/PTPRZ1 pathway to reduce PTP activity, and this reduction in activity interrupts protein tyrosine phosphorylation, suppresses UM proliferation and metastasis and improves cisplatin sensitivity in UM cells. Then, to overcome the limitations of the difficulty of drug administration and traditional therapeutics, the indocyanine green (ICG)-labeled manganese metal–organic framework (MOF) nanoparticles (NPs) were fabricated and linked with arginine-glycine-aspartate (RGD) peptide to carry siOUM1/siPTPRZ1 and cisplatin to achieve targeted siRNA interference-mediated therapy, enhanced cisplatin therapy and chemodynamic therapy. This NP system also has a dual-modal imaging ability because ICG is a near-infrared region fluorescent dye and manganese has the potential to be used in magnetic resonance imaging. This study verifies the significance of the newly discovered lncRNA OUM1 as a new therapeutic target for aggressive UM and provides a drug delivery NP system for precise treatment of UM accompanied with a dual-modal imaging ability.Graphical

SERS Monitored Kinetic Process of Gaseous Thiophenol Compound in Plasmonic MOF Nanoparticles.

Benefiting from the electromagnetic enhancement of noble metal nanoparticles (NPs) and the capture ability of organic frameworks, plasmonic metal-organic framework (MOF) structures have greatly promoted the development of gas detection by surface-enhanced Raman spectroscopy (SERS). In those detections, the kinetic process of gaseous molecules in plasmonic-MOF structures has a great influence on SERS spectra, which is still lacking intensive investigation in previous reports. In this work, the kinetic processes of gaseous thiophenol compounds (TPC) in the plasmonic Zeolitic Imidazolate Framework (Ag@ZIF) core-shell NPs are studied by SERS spectra. The experimental data demonstrate that the SERS intensities of gaseous TPC could be enhanced once more in an H2 mixed gas environment with different functional groups of TPC. Further results reveal that the two-step enhancement of SERS intensities is not only related to the thicknesses of the MOF shell but also affected by the ambient mixed gas. To understand this novel phenomenon, the binding energy between the gaseous molecule and ZIF is calculated based on first-principles computation. In combination with the plasmonic properties of the Ag core, a molecular collision model is introduced here to show the distribution of gaseous TPC molecules in ZIF, which could be responsible for this interesting two-step enhancement of SERS intensities. Furthermore, the H2 assisted kinetic process of gaseous p-aminothiophenol (PATP) is also analyzed by the classical pseudo-first-order kinetic model, which is consistent with our experimental SERS data. Our work not only reveals the novel phenomenon of plasmonic-MOF structures to improve the gas detection by SERS spectra but also enriches the understanding of the microcosmic process of gaseous molecules in the mixed gas environment to optimize MOF structures for gas capture and storage.

Prostate-Specific Antigen Monitoring Using Nano Zinc(II) Metal-Organic Framework-Based Optical Biosensor.

The prostate-specific antigen (PSA) is an important cancer biomarker that is commonly utilized in the diagnosis of prostate cancer. The development of a PSA determination technique that is rapid, simple, and inexpensive, in addition to highly accurate, sensitive, and selective, remains a formidable obstacle. In this study, we developed a practical biosensor based on Zn(II) metal-organic framework nanoparticles (Zn-MOFs-NPs). Many spectroscopic and microanalytical tools are used to determine the structure, morphology, and physicochemical properties of the prepared MOF. According to the results, Zn-MOFs-NPs are sensitive to PSA, selective to an extremely greater extent, and stable in terms of chemical composition. Furthermore, the Zn-MOFs-NPs did not exhibit any interferences from other common analytes that might cause interference. The detection limit for PSA was calculated and was 0.145 fg/mL throughout a wide linear concentration range (0.1 fg/mL-20 pg/mL). Zn-MOFs-NPs were successfully used as a growing biosensor for the monitoring and measurement of PSA in biological real samples.

Rational Design of 3-Dimensional Carbon Architectures with Controlled Interfacial Activity for Reversible Li Metal Storage

Three-dimensional (3D) host architectures for Li metal storage have emerged as promising strategies for resolving the critical issues of Li metal anodes: severe volume changes and dendritic growth of Li during charge–discharge processes. However, the ionic resistance of electrolyte-filled pores causes the preferential deposition of Li on top of the 3D architecture (i.e., top plating), resulting in early cell failure. To realize Li metal anodes with high capacity and cyclability, herein, we report 3D-architectured electrodes with controlled interfacial activity based on metal–organic framework (MOF)-derived carbon hosts. Electrochemical simulations of Li plating processes in the 3D-architectured electrode suggest that the top plating can be effectively suppressed by increasing the interfacial activity across the thickness toward bottom of the electrode. MOF nanoparticles are pyrolyzed to form highly porous carbon hosts, and then, atomic Ag clusters are incorporated into the host by a galvanic displacement reaction to enhance the interfacial activity. A bi-layered carbon electrode with controlled interfacial activity is fabricated via sequential electrophoretic deposition of the host materials: i.e., as-pyrolyzed carbon on top and Ag-incorporated carbon on bottom. In comparison with the conventional electrode with uniform interfacial activity, the bi-layered electrode exhibits reduced overpotentials for Li plating and enhanced cyclability during galvanostatic Li plating–stripping. The combined computational and experimental studies further demonstrate that the bottom layer with atomic Ag clusters acts as a preferential site for Li nucleation even in the presence of kinetic limitations of ionic transport. As a result, Li deposits are confined in the bi-layered carbon electrode, thereby enhancing the reversibility of Li metal storage. This work provides an effective strategy to develop long-cycling, high-capacity Li metal anodes by controlling the interfacial activity of 3D carbon architectures.

Metal–Organic Framework Nanoparticle Films for Surface-Enhanced Raman Spectroscopy-Based Autograding in the Odor Intensity of Gas Mixture Generated from Kitchen Waste

As few odorous molecules in a gas mixture make a great contribution to its odor intensity, autograding in odor intensity is the key process and of great challenge in the prevention of odor pollution. In this work, the surface-enhanced Raman spectroscopy (SERS) spectra of a gas mixture from kitchen waste are detected on plasmonic MOF nanoparticle (NP) films for autograding in odor intensity. To obtain plasmonic MOF NP films with high SERS sensitivity, AgNP@ZIF-8 NPs with different shell thicknesses and adsorbing times are investigated, which is further confirmed by the simulation of electric field distribution and airflow distribution. Then, a 45 nm shell thickness and 3H adsorbing time are selected to collect the SERS spectra of the gas mixture from kitchen waste with different odor intensities. These SERS spectra point out that the odorous molecules generated from the different statuses of kitchen waste dominate the odor intensity of the gas mixture. Furthermore, autograding in odor intensities with four levels based on deep learning (DL) is achieved here. The results exhibit excellent diagnostic accuracy (93.3%) for the external held-out overall dataset, which indicates that a high-throughput, rapid, and label-free tool for screening odor intensities could be developed. Our work not only enriches the research of gas detection by SERS spectra but also improves the prevention technique of odor pollution.

Advanced formulations and nanotechnology-based approaches for pulmonary delivery of sildenafil: A scoping review.

Oral sildenafil (SDF) is used to treat pulmonary arterial hypertension (PAH), and its bioavailability is approximately 40%. Several formulations of nano and microparticles (for pulmonary delivery) are being developed because it is possible to improve characteristics such as release time, bioavailability, dose, frequency, and even directly target the drug to the lungs. This review summarizes the latest SDF drug delivery systems for PAH and explains challenges related to the development, the preclinical, and the clinical studies. A scoping review was conducted by searching electronic databases including PubMed, Scopus, and Web of Science to identify studies published between 2001 and 2021. From 300 articles found, 31 met the inclusion criteria. This review identified colloidal formulations such as polymeric, lipid, and metal-organic framework nanoparticles. Strategies were determined to reach the deep airways such as polymeric microparticles, large porous microparticles, nanocomposites, and nano in microparticles. Finally, aspects related to toxicological, pharmacokinetics, and gaps in information for potential use in humans were discussed. SDF formulations are significant candidates for the treatment of PAH by inhalation. In summation, future preclinical studies are still required in large animals, as there is no particular formulation yet submitted to clinical studies.