Enhancement of Visible Light Antibacterial Activities of Cellulose Fibers from Lotus Petiole Decorated ZnO Nanoparticles.

Cellulose/ZnO (CZ) nanocomposites are promising antimicrobial materials known for their antibiotic-free nature, biocompatibility, and environmental friendliness. In this study, cellulose fibers extracted from lotus petioles were utilized as a substrate and decorated with various shapes of ZnO nanoparticles (NPs), including small bean, hexagonal ingot-like, long cylindrical, and hexagonal cylinder-shaped NPs. Increasing zinc salt molar concentration resulted in highly crystalline ZnO NPs forming and enhanced interactions between ZnO NPs and -OH groups of cellulose. The thermal stability and UV-visible absorption properties of the CZ samples were influenced by ZnO concentration. Notably, at a ZnO molar ratio of 0.1, the CZ 0.1 sample demonstrated the lowest weight loss, while the optical band gap gradually decreased from 3.0 to 2.45 eV from the CZ 0.01 to CZ 1.0 samples. The CZ nanocomposites exhibited remarkable antibacterial activity against both Staphylococcus aureus (S. aureus, Gram-positive) and Escherichia coli (E. coli, Gram-negative) bacteria under visible light conditions, with a minimum inhibitory concentration (MIC) of 0.005 mg/mL for both bacterial strains. The bactericidal effects increased with higher concentrations of ZnO NPs, even achieving 100% inhibition. Incorporating ZnO NPs onto cellulose fibers derived from lotus plants presents a promising avenue for developing environmentally friendly materials with broad applications in antibacterial and environmental fields.

Ionic liquid-immobilized silica gel as a new sorbent for solid-phase extraction of heavy metal ions in water samples.

In the current study, we have developed a solid-phase extraction (SPE) method with novel C18-alkylimidazolium ionic liquid immobilized silica (SiO2-(CH2)3-Im-C18) for the preconcentration of trace heavy metals from aqueous samples as a prior step to their determination by inductively coupled plasma mass spectrometry (ICPMS). The material was characterized by Fourier-transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA), Energy-Dispersive X-ray Spectroscopy (EDS), and Brunauer-Emmett-Teller (BET) analysis. A mini-column packed with SiO2-(CH2)3-Im-C18 sorbent was used for the extraction of the metal ions complexed with 1-(2-pyridylazo)-2-naphthol (PAN) from the water sample. The effects of pH, PAN concentration, length of the alkyl chain of the ionic liquid, eluent concentration, eluent volume, and breakthrough volume have been investigated. The SiO2-(CH2)3-Im-C18 allows the isolation and preconcentration of the heavy metal ions with enrichment factors of 150, 60, 80, 80, and 150 for Cr3+, Ni2+, Cu2+, Cd2+, and Pb2+, respectively. The limits of detection (LODs) for Cr3+, Ni2+, Cu2+, Cd2+, and Pb2+ were 0.724, 11.329, 4.571, 0.112, and 0.819 µg L-1, respectively with the relative standard deviation (RSD) in the range of 0.941-1.351%.

Synthesis of 5-hydroxymethylfurfural from monosaccharides catalyzed by superacid VNU-11-SO4 in 1-ethyl-3-methylimidazolium chloride ionic liquid.

Superacid VNU-11-SO4, a modified metal-organic framework by post-synthetic treatment with a sulfuric acid solution, has been considered as a promising heterogeneous catalyst in the isomerization of glucose to fructose and further dehydration to form 5-hydroxymethylfurfural (HMF) due to its possession of both Lewis and Brønsted acid sites. In this work, we focused on using VNU-11-SO4 for the optimization of the conversion of fructose and glucose into HMF using an ionic liquid as a green solvent. The highest yields of HMF from glucose and fructose could be obtained in 28% (140 °C, 8 h) and 86% (110 °C, 3 h), respectively, with the use of VNU-11-SO4 catalyst in 1-ethyl-3-methylimidazolium chloride ionic liquid. Recycling examination of the catalyst showed only a slight decrease in the HMF yield, implying its potential industrial application in biomass transformation.

Hydrogen adsorption mechanism of MOF-74 metal-organic frameworks: an insight from first principles calculations.

The microscopic mechanism of the H2 adsorption of two Mg-MOF-74 isoreticular frameworks, one with a benzenedicarboxylate (BDC) linker and the other with a dihydroxyfumarate (DHF) linker, were studied on the basis of density functional theory (DFT) method. Possible adsorption sites on the internal surface of the two MOFs were detected using ab initio molecular dynamics (AIMD) annealing simulations. The simulations were able to reproduce all adsorption sites which have been experimentally observed for the BDC-based M-MOF-74 frameworks with M = Ni and Zn. In descending order of binding strengths, they are the adsorption sites primarily induced by the open metal sites P1, the oxygen atoms of the oxido groups P2 and the aromatic rings P3. The H2-framework binding strengths were properly evaluated by taking into account the vibrational zero-point energy (ZPE) contribution. An additional type of adsorption sites induced by the oxygen atoms of the carboxyl groups P4 is predicted for the Mg-MOF-74 framework. Two types of adsorption sites primarily induced by the open metal sites P1 and oxygen atoms of the carboxyl groups P2 were predicted for the DHF-based Mg-MOF-74 framework. Detailed analysis of the electron density showed that the electrostatic interaction of the H2 molecule with the charge distribution of the local framework environment within a radius of ∼3.5 Šis a key factor to define adsorption positions and binding strength. The absence of the P4 sites in the BDC-based Zn-MOF-74 framework is caused by the lower charge density at the oxygen atoms induced by less electro-positive metal. The substitution of the nonaromatic DHF linker for the aromatic BDC linker reduces the binding strength at the metal induced adsorption sites by 1.45 kJ mol-1 due to the absence of the aromatic ring.

A mild and efficient method for the synthesis of pyrroles using MIL-53(Al) as a catalyst under solvent-free sonication.

A highly efficient method for the synthesis of pyrroles using MIL-53(Al) as a catalyst has been developed under solvent-free sonication. This reaction has a broad substrate scope and high yields were obtained within a short reaction time. Remarkably, no additional additives and volatile organic solvent are required for this method and the MIL-53(Al) could be recovered and reused several times without significant drop-off in catalytic activity.

Anticancer Drug Delivery Capability of Biodegradable PMO in the Chicken Egg Tumor Model.

Biodegradable PMO (Periodic Mesoporous Organosilica) has emerged as a promising type of mesoporous silica based nanoparticles for clinical translation. We as well as others have synthesized and characterized three types of nanoparticles containing disulfide, tetrasulfide or peptide-like bonds within their framework. Biodegradable PMO has high drug loading efficiency and can be taken up into cancer cells. Our experiments utilizing the chicken egg tumor model uncovered excellent capability to accumulate and deliver anticancer drugs to the tumor. These results will be described and their significance will be discussed. The chicken egg tumor model provides a convenient and versatile model for characterizing nanoparticles.

Tumor Targeting and Tumor Growth Inhibition Capability of Mesoporous Silica Nanoparticles in Mouse Models.

Mesoporous silica nanoparticles (MSNs) provide a promising vehicle for anticancer drug delivery. Various animal studies point to the efficacy of this nanoparticle for delivering anticancer agents (drug and siRNA) to inhibit tumor growth. These studies also showed tumor accumulation of MSN nanoparticles. While the extent of tumor accumulation differed, the study showed that it is possible to achieve significant accumulation of nanoparticles in the tumor. Biocompatibility and safety of MSN were also demonstrated by these studies.

Chick chorioallantoic membrane assay as an in vivo model to study the effect of nanoparticle-based anticancer drugs in ovarian cancer.

New therapy development is critically needed for ovarian cancer. We used the chicken egg CAM assay to evaluate efficacy of anticancer drug delivery using recently developed biodegradable PMO (periodic mesoporous organosilica) nanoparticles. Human ovarian cancer cells were transplanted onto the CAM membrane of fertilized eggs, resulting in rapid tumor formation. The tumor closely resembles cancer patient tumor and contains extracellular matrix as well as stromal cells and extensive vasculature. PMO nanoparticles loaded with doxorubicin were injected intravenously into the chicken egg resulting in elimination of the tumor. No significant damage to various organs in the chicken embryo occurred. In contrast, injection of free doxorubicin caused widespread organ damage, even when less amount was administered. The lack of toxic effect of nanoparticle loaded doxorubicin was associated with specific delivery of doxorubicin to the tumor. Furthermore, we observed excellent tumor accumulation of the nanoparticles. Lastly, a tumor could be established in the egg using tumor samples from ovarian cancer patients and that our nanoparticles were effective in eliminating the tumor. These results point to the remarkable efficacy of our nanoparticle based drug delivery system and suggests the value of the chicken egg tumor model for testing novel therapies for ovarian cancer.