Porous Aluminum-Based Metal-Organic Framework-Aminoclay Nanocomposite: Sustainable Synthesis and Ultrahigh Sorption of Cephalosporin Antibiotics

Exploring the state-of-the-art in metal-organic frameworks for antibiotic adsorption: a review of performance, mechanisms, and regeneration

The application of metal-organic frameworks (MOFs) towards the adsorption of antibiotics is a new and emerging area of study. The rise in use or misuse of antibiotic products has exacerbated their ongoing presence and persistence in the natural environment. Even at low concentrations, antibiotic residues exert pressure on bacterial populations, eventually leading to the emergence of resistant bacteria. Metal-organic frameworks, known for their high porosity, vast specific surface area, and ease of modification, have emerged to be a promising and sustainable antibiotic adsorbent. In an effort to advance the development of this adsorbent, this study provides a state-of-the-art review of recent research published from 2020 to the present, specifically examining the use of MOFs for removing antibiotics from aqueous solutions. Multiple MOF adsorbents were analyzed, with approximately 59% demonstrating significant adsorption capacity within the pH range of 6.0-8.0. In 75% of the instances, the adsorption system reached equilibrium in under 2 hr. Adsorption capacities compared well to other published works in the literature and exceeded conventional adsorbents in many instances. Notable cases of MOF performance were MIL-53(Al) adsorption of amoxicillin (AMX) and SA-g-P3AP@MOF(Fe)/Ag adsorption of neomycin where adsorption capacities of 758.5 and 625.0 mg/g were attained, respectively. The reusability of MOFs was extensively reported at the laboratory batch scale. Analysis of the reported studies revealed the most effective eluents were acetone, ethanol, and methanol, with mostly 3-5 cycles attainable without appreciable loss in efficiency. The recent literature confirmed that MOFs are highly efficient in the adsorption of antibiotics; however, there are some areas that warrant further development. It is intended that this work will bring recent trends to the forefront, identify knowledge gaps, and help guide future research proposals.

Influence of soil type on bacterial growth and tolerance to experimentally added human antibiotics

The human antibiotics cefuroxime (CXM) and azithromycin (AZI) are among the most commonly prescribed. A significant portion of both are excreted and has been detected in sewage treatment plant effluents. The increasing use of such effluents in crops for irrigation and as fertilisers poses a threat to soil microbiota because of the presence of antibiotics. The lack of studies on CXM and AZI in soils hinders our understanding of their potential toxic effects on soil bacterial communities and ecosystem services. This study significantly contributes to the literature by quantifying the toxicity of CXM and AZI at varying concentrations in 12 different crop soils and tracking their evolution over time. The study also examined whether antibiotic pressure led to the development of more tolerant bacterial communities. The results of this study are the values of the logarithm of the antibiotic concentration at which 50 % of bacterial growth is inhibited (Log IC50) and indicate that both antibiotics are toxic to soil bacteria. The direct toxicity of CXM (1 day after contamination) was higher (Log IC50: 0.9 = 7.9 mg kg-1) than that of AZI (Log IC50: 3.4 = 2362 mg kg-1). However, bacterial growth was less affected by CXM over time, whereas AZI remained toxic in some soils until day 42 (Log IC50: 3.2 = 1533 mg kg-1 and 3.4 = 2291 mg kg-1, respectively). The overall results indicate that selective pressure exerted by antibiotics generates antibiotic tolerance in soils, even at the lowest antibiotic concentration studied (7.8 mg kg-1). The general trend was to increase tolerance to higher antibiotic concentrations up to the highest concentration studied (2000 mg kg-1). However, the degree of tolerance developed was highly dependent on soil type. More studies should be conducted to quantitatively assess the toxic and tolerance-developing effects of antibiotics in soils. Such information will be valuable for identifying which antibiotics pose a threat to the soil microbiota and consequently to human health.

Integration of metal-organic frameworks and clay toward functional composite materials

Metal-organic frameworks (MOFs) have become increasingly important as a class of porous crystalline materials because of their diverse applications. At the same time, significant progress has been achieved in the field of MOF-based composite materials toward novel applications based on the synergistic effect of two or more different components. Clay materials have been explored recently in MOF chemistry for the synthesis of MOF-clay composites, which are a new class of functional materials synthesized by a cooperative combination of MOFs with clay. Such composites have evolved only in the recent past with important functions and applications, such as enhanced gas storage and separation, CO2 capture and conversion, catalysis, drug delivery, and water harvesting. Notably, the typical shortcomings of MOFs, such as moisture sensitivity, poor water dispersibility, poor thermal and chemical stability, and poor processability, could be overcome by developing novel MOF-clay composites. This article provides a concise overview of MOF-clay composites and their applications in various fields that will drive the interest of researchers to explore the emerging field of MOF-clay chemistry. In the initial sections, we classify the clays that have been used in MOF chemistry and briefly discuss their structures and chemistry. We also present the advantages of MOF-clay composites and discuss their synthetic methodologies. In the later sections, we classify different MOF-clay composites based on the clay and present some representative examples of such composites that show unique properties and applications. Finally, the development in this field is summarized, and the future scope of such composites is discussed.

Advancements and Challenges in the Application of Metal-Organic Framework (MOF) Nanocomposites for Tumor Diagnosis and Treatment

Nanoscale metal-organic frameworks (MOFs) offer high biocompatibility, nanomaterial permeability, substantial specific surface area, and well-defined pores. These properties make MOFs valuable in biomedical applications, including biological targeting and drug delivery. They also play a critical role in tumor diagnosis and treatment, including tumor cell targeting, identification, imaging, and therapeutic methods such as drug delivery, photothermal effects, photodynamic therapy, and immunogenic cell death. The diversity of MOFs with different metal centers, organics, and surface modifications underscores their multifaceted contributions to tumor research and treatment. This review is a summary of these roles and mechanisms. The final section of this review summarizes the current state of the field and discusses prospects that may bring MOFs closer to pharmaceutical applications.

In vitro investigation of wound healing performance of PVA/chitosan/silk electrospun mat loaded with deferoxamine and ciprofloxacin

Electrospinning is an advanced method used for developing wound dressings. Biopolymer-based electrospun mats have been extensively studied in tissue engineering due to their similarity to the extracellular matrix. In this study, electrospun poly(vinyl alcohol)/chitosan/silk fibroin (PChS) mat demonstrated improved mechanical properties, including tensile strength, strain at break, and Young's modulus, compared to electrospun poly(vinyl alcohol) and poly(vinyl alcohol)/chitosan mats. Similarly, the swelling capability, thermal stability, and hydrophilicity were higher in the PChS mat compared to the other ones. Hence, the PChS mat was selected for further investigation. Ciprofloxacin (CIP) was added to the PChS electrospinning solution at 5 % and 10 % concentration, and deferoxamine (DFO) was immobilized on CIP-loaded mats at 1 and 2 g/L concentration using a polydopamine linker. Evaluating mats with the dimensions of 1 × 1 cm2 showed that those containing 5 % and 10 % CIP exhibited bactericidal activity against Escherichia coli and Staphylococcus aureus. Moreover, Human dermal fibroblast cells were compatible with the fabricated mats, as confirmed by the MTT assay. Finally, drug-loaded mats had a positive effect on wound healing in a scratch test, and mats with 10 % CIP and 2 g/L DFO showed the highest effect on promoting wound healing, indicating potential for use as a wound dressing.

Aminated Multiwalled Carbon Nanotube-Doped Magnetic Flower-like WSe2 Nanosheets for Efficient Adsorption in Acidic Wastewater

The water body environment is related to ecological and human health. Adsorption is an effective means to remove pollutants from water bodies. Currently, the common adsorbents suffer from disadvantages such as structural instability and poor adsorption performance under acidic conditions, which not only affect the adsorption efficiency but also cause secondary pollution of water bodies. In this study, a novel aminated multiwalled carbon nanotube-doped flower-like nanocomposite was designed, where the anionic or neutral groups were protonated under acidic conditions, and it displayed a higher adsorption capacity for dyes by ion exchange, represented by methylene blue (MB) and rhodamine B (RB). WSe₂ in the composite increases its adsorption sites. The adsorption efficiency of pollutants in acidic wastewater was enhanced while avoiding secondary contamination. The synthesized composites showed maximum adsorptions of 27.55 and 27.47 mg/g for MB and RB, respectively. The current work offers a novel approach to treating acidic wastewater.