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Metal–organic frameworks (MOFs) are crystalline porous materials with a broad range of practical applications. A plethora of MOFs based on a variety of metal ions including s-, p-, d-, and f-block elements have been developed over the past decade. Despite the abundance, cheapness, and recognized non-toxicity, s-block MOFs are less explored than those of MOFs based on transition metals and f-block metal ions. Given that s-block MOFs adopt outstanding features (e.g., low density, dense Lewis active centers and open metal sites, biocompatibility, and high catalytic activity), they have been used for potential applications such as gas storage and separation, chemical delivery, catalysis, electrochemical applications, and sensing. This review includes the recent advances of s-block MOFs. The properties of MOFs based on s-block metal ions are the first aspect in our discussion; the second one is the description of the chemical structures of s-block MOF constituents including organic linkers and metal clusters; furthermore, the function of crystal structures and applications of s-block MOFs are specially addressed in gas sorption and separation, chemical delivery, catalysis, sensing, and others types of practical applications. Providing viewpoints on how to expand the scope of s-block MOF chemistry is considered as our final goal in an attempt to orient the chemistry, properties, applications, and future directions of s-block MOFs as advanced materials for multiple purposes in the future.

Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) bacteria acquired serious bacterial resistance against antibiotics. Untreated dangerous infections can cause death. We proposed nanofibers (NFs) of Polyvinyl alcohol (PVA)/Chitosan (CS) nanocomposite embedded with Chicory root extract (CRE) as a safe solution. We determined the best extraction solvent and drying method, 70 % ethanol and freeze-drying, respectively. We investigated the optimal electrospinner parameters for a smooth PVA/CS NFs. Finally, we discovered PVA/CS/CRE-50 mg (F4) to be the most effective antibacterial and antioxidant CRE concentration. Interestingly, it was found that ethanolic extract had the highest yield % at 24.7 % with Total Phenolic Contents (TPC) of 4 mg Gallic Acid Equivalent (GAE)/1 g, 80 % antioxidant activity at 25 mg with an IC50 of 4.15 mg/mL and a Minimum Bactericidal Concentration (MBC) of 100 mg against S. aureus and 25 mg against E. coli. Remarkably, F4 NFs had an IC50 33.32 mg/mL, Entrapment Efficiency 64.89 %, Loading Capacity 4.41 %, obeying Noyes-Whitney release model. F4 had an MBC of 2 mg with both bacterial strains, which proved to be potent antibacterial material that surpasses the pure extract 50 times. F4 has also shown an extraordinary antioxidant activity that exceeds PVA/CS NF activity 23 times.

Inspired by the rampant digestive disorders and the vast bacterial infections, this study aimed at fabricating nanofibers made of inulin/polyvinyl alcohol (PVA) composite nanofibers (CNFs) using the electrospinning technique and testing their prebiotic and antibacterial activities. The inulin/PVA CNFs were tested for prebiotic activity with Lactobacillus species while Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were used to assess the antibacterial potentiality. During the fabrication of the CNFs, different electrospinning parameters have been carefully controlled, in order to produce nanofibers with relatively uniform diameter, fewer beads, and high integrity. The different parameters included variable solution concentration (material ratio varied from 14 to 20 wt %), applied voltage (varied from 15 to 25 kV), and solution flow (ranged between 0.005 and 0.5 mL/min). The chemical characteristics, thermal stability, and morphology of the formed CNFs were comprehensively characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. Selected CNFs, showing the best diameter uniformity and integrity, were tested for the prebiotic and antimicrobial activity. A 38% increase in prebiotic activity of CNFs, compared to their bulk solution, was observed. The antibacterial activity of the selected CNFs was enhanced, from ∼40% (pure inulin) to 70% (inulin/PVA CNFs) against E. coli and 45% against S. aureus. This study investigates the prebiotic and antibacterial activities of PVA/inulin CNFs and provides the foundation for inulin/PVA CNF use in the healthcare sector, as in disinfectants and/or digestive disorders.

Due to the current challenges faced by the increasing rate of drug-resistant bacteria, attention is gradually shifting from synthetic antimicrobial chemical compounds to natural products that are ecofriendly with a wide spectrum of properties. The aim of this research was to successfully fabricate electrospun nanofibers from poly(vinyl alcohol) (PVA), PVA blended with Bidens pilosa and chitosan composite blends and investigate their potential antibacterial activities against Escherichia coli and Staphylococcus aureus. Fabrication of nanofibers was performed by the electrospinning technique, which applies high voltage on the polymer, forcing it to spin off as a jet onto a plate collector. Characterization of the nanofibers was successfully performed by scanning electron microscopy and Fourier transform infrared spectroscopy. Antibacterial assessment was carried out by colony forming unit enumeration. The results obtained revealed a 12% increase in growth inhibition of bacteria in composite nanofibers as compared with their parental forms, which were >91 and 79%, respectively. Chitosan nanofibers have been extensively researched, and their antibacterial properties have been studied. However B. pilosa antibacterial properties in a nanofiber form have not been previously reported. These composite nanofibers open new avenues toward using natural materials as potent antibacterial agents.

Essential oils (EOs) such as Peppermint oil (PO) and Green Tea oil (GTO) have extensively been reported for their nutritional and biomedical properties. To overcome the sensitivity of EOs to the environmental conditions, nano-encapsulation has emerged as a method to address this limitation. In this work, PO and GTO were encapsulated in chitosan nanoparticles (CS NPs) following emulsification/ionic gelation method. The nano-encapsulated PO (CS/PO NPs) and GTO (CS/GTO NPs) were fully characterized by various methods. Spherical NPs with an average size range of 20–60 nm were revealed by TEM for both systems. The loading capacity reached 22.2% and 23.1%, for PO and GTO, respectively, and the in-vitro release followed a Fickian behavior in different buffer systems. The TGA thermograms of both nano-encapsulated EOs showed an increase in the temperature of maximum degradation rate up to 350 °C. The nano-encapsulation maintained the stability of the total phenolic contents in both EOs, improved the antioxidant activity by ~2 and 2.4-fold for PO and GTO respectively. Surprisingly, the antibacterial activity of CS/GTO NPs was more potent than CS/PO NPs and especially against Staphylococcus aureus with ~9.4 folds improvement compared to pure GTO, and ~4.7 fold against Escherichia coli.