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Journal of Hazardous Materials Jun 2024Covalent organic frameworks (COFs) are a type of novel organic catalysts which show great potential in the treatment of environmental contaminations. Herein, we...
Covalent organic frameworks (COFs) are a type of novel organic catalysts which show great potential in the treatment of environmental contaminations. Herein, we synthesized three isoreticular halogen-functionalized (F, Cl and Br) porphyrin COFs for visible-light (420 nm ≤ λ ≤ 780 nm) photocatalytic reduction of Cr(VI) to Cr(III). Halogen substituents with tunable electronegativity can regulate the band structure and modulate the charge carrier kinetics of COFs. In the absence of any sacrificial reagent, the isoreticular COFs exhibited good photocatalytic reduction activity of Cr(VI). Particularly, the TAPP-2F showed nearly 100 % conversion efficiency and the highest reaction rate constants (k) on account of the strong electronegativity of F substituent. Experimental results and theoretical calculations showed that the conduction band (CB) potentials of COFs became more negative and charge carrier separation increased with the enhancement of electronegativity (Br < Cl < F), which could provide sufficient driving force for the photoreduction of Cr(VI) to Cr(III). The halogen substituents strategy for regulating the electronic structure of COFs can provide opportunities for designing efficient photocatalysts for environmental remediation. Meanwhile, the mechanistic insights reported in this study help to understand the photocatalytic degradation pathways of heavy metals.
PubMed: 38917630
DOI: 10.1016/j.jhazmat.2024.134956 -
ACS Applied Materials & Interfaces Jun 2024Covalent organic frameworks (COFs) are ideal platforms to spatially control the integration of multiple molecular motifs throughout a single nanoporous framework....
Covalent organic frameworks (COFs) are ideal platforms to spatially control the integration of multiple molecular motifs throughout a single nanoporous framework. Despite this design flexibility, COFs are typically synthesized using only two monomers. One bears the functional motif for the envisioned application, while the other is used as an inert connecting building block. Integrating more than one functional motif extends the functionality of COFs immensely, which is particularly useful for multistep reactions such as electrochemical reduction of CO. In this systematic study, we synthesized five Ni(II)- and Zn(II)-porphyrin-based COFs, including two pure component COFs (Ni and Zn) and three mixed Ni/Zn-COFs (Ni/Zn, Ni/Zn, and Ni/Zn). Among these, the Ni/Zn-COF exhibited the highest catalytic performance for the electroreduction of CO to CO and formate at -0.6 V vs RHE, as was observed in an H-cell. The catalytic performance of the COF catalysts was further extended to a zero-gap membrane electrode assembly (MEA) operation where, utilizing Ni/Zn, CH was detected along with CO and formate at a high current density of 150 mA cm. In contrast, under these conditions predominantly H and CO were detected at Ni and Zn respectively, indicating a clear synergistic effect between the Ni- and Zn-porphyrin units.
PubMed: 38914515
DOI: 10.1021/acsami.4c02511 -
Inorganic Chemistry Jun 2024Two new vanadyl complexes of N-confused porphyrins (NCPs), [VONCTPP] () and [VONCP(OMe)] (), have been synthesized for the first time and investigated as a catalyst for...
Two new vanadyl complexes of N-confused porphyrins (NCPs), [VONCTPP] () and [VONCP(OMe)] (), have been synthesized for the first time and investigated as a catalyst for the oxidative bromination reaction of phenol and its derivatives. This article further delineates crystal structures, photophysical, and redox properties of both the vanadyl complexes. Complexes and exhibited a significant red shift in their absorption spectra compared with their respective free bases. The single-crystal structure of revealed that the complex is in the 2H tautomeric form, while EPR studies revealed the +4 oxidation state of vanadium metal having an axial compression with d configuration. Catalytic potential for -like activity has been explored for both complexes and for the first time in NCP chemistry with excellent TOF values (4.7-6.3 s for and 7.3-8.7 s for ) using KBr as a source of bromine and HO as a green oxidant in aqueous acidic medium at 298 K. Notably, both catalysts show excellent recyclability over five cycles. The vanadyl-metalated NCPs exhibit excellent stability in the air.
PubMed: 38912934
DOI: 10.1021/acs.inorgchem.4c01222 -
Nano Letters Jun 2024Wound infections, especially those caused by pathogenic bacteria, present a considerable public health concern due to associated complications and poor therapeutic...
Wound infections, especially those caused by pathogenic bacteria, present a considerable public health concern due to associated complications and poor therapeutic outcomes. Herein, we developed antibacterial nanoparticles, namely, PGTP, by coordinating guanidine derivatives with a porphyrin-based sonosensitizer. The synthesized PGTP nanoparticles, characterized by their strong positive charge, effectively disrupted the bacterial biosynthesis process through charge interference, demonstrating efficacy against both Gram-negative and Gram-positive bacteria. Additionally, PGTP nanoparticles generated reactive oxygen species under ultrasound stimulation, resulting in the disruption of biofilm integrity and efficient elimination of pathogens. RNA-seq analysis unveiled the detailed mechanism of wound healing, revealing that PGTP nanoparticles, when coupled with ultrasound, impair bacterial metabolism by interfering with the synthesis and transcription of amino acids. This study presents a novel approach to combatting wound infections through ultrasound-driven charge-interfering therapy, facilitated by advanced antibacterial nanomaterials.
PubMed: 38912706
DOI: 10.1021/acs.nanolett.4c00930 -
ACS Omega Jun 2024Water electrolysis for clean hydrogen production requires high-activity, high-stability, and low-cost catalysts for its particularly sluggish half-reaction, the oxygen...
Water electrolysis for clean hydrogen production requires high-activity, high-stability, and low-cost catalysts for its particularly sluggish half-reaction, the oxygen evolution reaction (OER). Currently, the most promising of such catalysts working in alkaline conditions is a core-shell nanostructure, NiFe@NC, whose Fe-doped Ni (NiFe) nanoparticles are encapsulated and interconnected by N-doped graphitic carbon (NC) layers, but the exact OER mechanism of these catalysts is still unclear, and even the location of the OER active site, either on the core side or on the shell side, is still debated. Therefore, we herein derive a plausible active-site model for each side based on various experimental evidence and density functional theory calculations and then build OER free-energy diagrams on both sides to determine the active-site location. The core-side model is an FeO-type (rather than NiO-type) active site where an Fe atom sits on Ni oxide layers grown on top of the core surface during catalyst activation, whose facile dissolution provides an explanation for the activity loss of such catalysts directly exposed to the electrolyte. The shell-side model is a NiN-type (rather than FeN-type) active site where a Ni atom is intercalated into the porphyrin-like NC site of the NC shell during catalyst synthesis. Their OER free-energy diagrams indicate that both sites require similar amounts of overpotentials, despite a complete shift in their potential-determining steps, i.e., the final O evolution from the oxophilic Fe on the core and the initial OH adsorption to the hydrophobic shell. We conclude that the major active sites are located on the core, but the NC shell not only protects the vulnerable FeO active sites on the core from the electrolyte but also provides independent active sites, owing to the N doping.
PubMed: 38911812
DOI: 10.1021/acsomega.3c09920 -
International Journal of Biological... Jun 2024Chitosan/zeolite-X (CHS/ZX) was synthesized to serve as an effective adsorbent for metal porphyrins through adsorption processes as an alternative to traditional...
Chitosan/zeolite-X (CHS/ZX) was synthesized to serve as an effective adsorbent for metal porphyrins through adsorption processes as an alternative to traditional separation methods from crude oil. The adsorption-desorption mechanisms of vanadyl and nickel tetraphenyl porphyrin (VO-TPP and Ni-TPP) were conducted on the model solution. Compared to individual components CHS and ZX, the CHS/ZX composite exhibited a doubled capacity for metal porphyrin removal. The synthesized composite was systematically characterized using FESEM, BET, XRD, FTIR, TGA, XPS, and CHN analyses. The study investigated the impact of many factors, including temperature, initial metal-porphyrin concentration, CHS/ZX dose, and contact time, on the adsorption efficiency of metal-porphyrin using CHS/ZX adsorbents. The adsorption processes of VO-TPP and Ni-TPP on CHS/ZX were effectively assessed through various equilibrium models, such as Langmuir, Freundlich, and Dubinin-Radushkevich (D-R). The pseudo-second-order model accurately depicted the adsorption processes of both VO-TPP and Ni-TPP. Determining the point of zero charge (pH) highlighted the composite's surface charge distribution. Furthermore, considering the ΔG° and ΔH° values, the adsorption processes at different temperatures are exothermic, and VO-TPP exhibits a greater adsorption capacity than Ni-TPP under similar conditions. Notably, 73.7 % of VO-TPP and 83.8 % of Ni-TPP that were adsorbed were successfully recovered.
PubMed: 38909734
DOI: 10.1016/j.ijbiomac.2024.133358 -
TAG. Theoretical and Applied Genetics.... Jun 2024A large fragment deletion of CpAPRR2, encoding a two-component response regulator-like protein, which influences immature white rind color formation in zucchini...
A large fragment deletion of CpAPRR2, encoding a two-component response regulator-like protein, which influences immature white rind color formation in zucchini (Cucurbita pepo). Fruit rind color is an important agronomic trait that affects commodity quality and consumer choice in zucchini (Cucurbita pepo). However, the molecular mechanism controlling rind color is unclear. We characterized two zucchini inbred lines: '19' (dark green rind) and '113' (white rind). Genetic analysis revealed white immature fruit rind color to be controlled by a dominant locus (CpW). Combining bulked segregant analysis sequencing (BSA-seq) and Kompetitive Allele-Specific PCR (KASP) markers, we mapped the CpW locus to a 100.4 kb region on chromosome 5 and then narrow down the candidate region to 37.5 kb using linkage analysis of 532 BC and 1613 F individuals, including 6 coding genes. Among them, Cp4.1LG05g02070 (CpAPRR2), encoding a two-component response regulator-like protein, was regarded to be a promising candidate gene. The expression level of CpAPRR2 in dark green rind was significantly higher than that in white rind and was induced by light. A deletion of 2227 bp at the 5' end of CpAPRR2 in '113' might explain the white phenotype. Further analysis of allelic diversity in zucchini germplasm resources revealed rind color to be associated with the deletion of CpAPRR2. Subcellular localization analysis indicated that CpAPRR2 was a nuclear protein. Transcriptome analysis using near-isogenic lines with dark green (DG) and white (W) rind indicated that genes involved in photosynthesis and porphyrin metabolism pathways were enriched in DG compared with W. Additionally, chlorophyll synthesis-related genes were upregulated in DG. These results identify mechanisms of zucchini rind color and provide genetic resources for breeding.
Topics: Fruit; Chromosome Mapping; Pigmentation; Phenotype; Cucurbita; Plant Proteins; Genetic Linkage; Gene Expression Profiling; Gene Expression Regulation, Plant; Alleles; Genes, Plant; Color; Transcriptome
PubMed: 38909110
DOI: 10.1007/s00122-024-04676-z -
Bioorganic Chemistry Jun 2024LD4, a novel porphyrin derivative, has attracted much attention for its excellent anti-inflammatory properties. It can promote the healing of colonic mucosa, reduce...
LD4, a novel porphyrin derivative, has attracted much attention for its excellent anti-inflammatory properties. It can promote the healing of colonic mucosa, reduce inflammatory response, regulate oxidative stress, and thus improve ulcerative colitis (UC) symptoms. However, the specific signaling pathways of LD4-PDT involved in UC have not been explored. The present study aimed to elucidate the effects of LD4 on UC and to investigate the underlying mechanisms both in vivo and in vitro. We classified and screened the LD4-PDT proteomic data to obtain key targets. Proteomic data revealed that EPHX2 and STAT3 are key targets of LD4-PDT for UC. Moreover, transcription factor STAT3 positively regulates the expression of EPHX2. Inhibiting EPHX2 can prevent the activation of NF-κB signaling pathway. Next, through pharmacological inhibition experiments, we confirmed that LD4-PDT can reduce intestinal inflammation by inhibiting STAT3-EPHX2 axis. However, by treating normal intestinal epithelial cells and colon cancer cells with TPPU and Stattic, our data confirmed that the STAT3-EPHX2 axis does not exist in colon cancer. In this study, we demonstrated that the transcription factor STAT3 can positively regulate the expression of EPHX2 in normal colon. LD4 can alleviate UC by inhibiting the STAT3-EPHX2 axis, but this axis does not exist in colon cancer. LD4-PDT may become a new and effective method for treating UC.
PubMed: 38908128
DOI: 10.1016/j.bioorg.2024.107579 -
Journal of Nanobiotechnology Jun 2024Hypoxia-activated prodrug (HAP) is a promising candidate for highly tumor-specific chemotherapy. However, the oxygenation heterogeneity and dense extracellular matrix...
BACKGROUND
Hypoxia-activated prodrug (HAP) is a promising candidate for highly tumor-specific chemotherapy. However, the oxygenation heterogeneity and dense extracellular matrix (ECM) of tumor, as well as the potential resistance to chemotherapy, have severely impeded the resulting overall efficacy of HAP.
RESULTS
A HAP potentiating strategy is proposed based on ultrasound responsive nanodroplets (PTP@PLGA), which is composed of protoporphyrin (PpIX), perfluoropropane (PFP) and a typical HAP, tirapazamine (TPZ). The intense vaporization of PFP upon ultrasound irradiation can magnify the sonomechanical effect, which loosens the ECM to promote the penetration of TPZ into the deep hypoxic region. Meanwhile, the PpIX enabled sonodynamic effect can further reduce the oxygen level, thus activating the TPZ in the relatively normoxic region as well. Surprisingly, abovementioned ultrasound effect also results in the downregulation of the stemness of cancer cells, which is highly associated with drug-refractoriness.
CONCLUSIONS
This work manifests an ideal example of ultrasound-based nanotechnology for potentiating HAP and also reveals the potential acoustic effect of intervening cancer stem-like cells.
Topics: Humans; Tirapazamine; Protoporphyrins; Fluorocarbons; Prodrugs; Cell Line, Tumor; Nanoparticles; Neoplastic Stem Cells; Antineoplastic Agents; Ultrasonic Waves; Animals; Extracellular Matrix; Mice; Neoplasms
PubMed: 38907270
DOI: 10.1186/s12951-024-02623-0 -
Bioorganic & Medicinal Chemistry Jun 2024The antimicrobial activity of new acid-functionalized porphyrins, with or without ultra-high irradiance, was investigated. Antibacterial efficacy was evaluated against...
Synthesis and characterization of new acid-functionalized porphyrins displaying antimicrobial activity against gram positive bacteria, yeasts and filamentous fungi with or without ultra-high irradiance.
The antimicrobial activity of new acid-functionalized porphyrins, with or without ultra-high irradiance, was investigated. Antibacterial efficacy was evaluated against Staphylococcus aureus (methicillin-resistant or methicillin-sensitive strains) and antifungal efficacy was evaluated against the yeast Candida albicans and the filamentous fungi Aspergillus fumigatus. Overall, the porphyrins tested are more effective against S. aureus. The best results were obtained with zinc diacid porphyrins 4 and 5 after only 3 min of ultra-high irradiation (500 mW/cm, 405 nm), demonstrating that acid-functionalized porphyrins are promising as novel antimicrobial drugs for surface disinfection.
PubMed: 38906069
DOI: 10.1016/j.bmc.2024.117810