Synthesis, characterization and antibacterial activity of [Zn(formato)2(4,4′-bipy)] complex

A rewritable and shape memory hydrogel doped with fluorescein-functionalized ZIF-8 for information storage and fluorescent anti-counterfeiting

The emergence of stimuli-responsive fluorescence anti-counterfeiting technology has garnered increasing attention in the era of intelligent internet. Smart fluorescent hydrogels combine the characteristics of luminous materials with the unique structure of hydrogels, offering the potential for dynamic reversible erasing and multi-tiered data encryption. In this work, a fluorescent hydrogel was constructed by zeolitic imidazolate framework-8 loaded with fluorescein and then mixed with polyvinyl alcohol hydrogel, sodium carboxymethyl cellulose and borax, which could be used for image hiding in visible light. The reversible bonds cross-linked fluorescent hydrogel was stretchable and self-healing with a three-dimensional network structure. The hydrogel presented bright green fluorescence under 365 nm UV light, which was quenched by adding copper ions. Meanwhile, the imprint of the hydrogel could be cleared by L-Cysteine and repeatedly recorded information many times. The alkali-induced shape memory capability was further utilized to achieve multi-tiered data encryption by deforming it to a 3D-specific shape through folding. The rewritable and multi-dimensional encrypted hydrogel is expected to improve data security and reduce resource consumption.

Multifunctional metal-organic frameworks as promising nanomaterials for antimicrobial strategies

Bacterial infections pose a serious threat to human health. While antibiotics have been effective in treating bacterial infectious diseases, antibiotic resistance significantly reduces their effectiveness. Therefore, it is crucial to develop new and effective antimicrobial strategies. Metal-organic frameworks (MOFs) have become ideal nanomaterials for various antimicrobial applications due to their crystalline porous structure, tunable size, good mechanical stability, large surface area, and chemical stability. Importantly, the performance of MOFs can be adjusted by changing the synthesis steps and conditions. Pure MOFs can release metal ions to modulate cellular behaviors and kill various microorganisms. Additionally, MOFs can act as carriers for delivering antimicrobial agents in a desired manner. Importantly, the performance of MOFs can be adjusted by changing the synthesis steps and conditions. Furthermore, certain types of MOFs can be combined with traditional photothermal or other physical stimuli to achieve broad-spectrum antimicrobial activity. Recently an increasing number of researchers have conducted many studies on applying various MOFs for diseases caused by bacterial infections. Based on this, we perform this study to report the current status of MOF-based antimicrobial strategy. In addition, we also discussed some challenges that MOFs currently face in biomedical applications, such as biocompatibility and controlled release capabilities. Although these challenges currently limit their widespread use, we believe that with further research and development, new MOFs with higher biocompatibility and targeting capabilities can provide diversified treatment strategies for various diseases caused by bacterial infections.

Antimicrobial zeolites and metal-organic frameworks

The current surge in antibiotic resistance and the emergence of pandemics have created an urgent need for novel antimicrobial strategies. The controlled release of antimicrobial active principles remains the most viable strategy to date, and transition metal ions currently represent the main alternative to antibiotics. In this review, we explore the potential of two types of materials, zeolites and metal-organic frameworks (MOFs), for the controlled release of antimicrobial active principles, notably transition metal ions. These materials have unique crystalline microporous structures that act as reservoirs, enabling sustained bactericidal effects in various applications such as coatings, packaging, and medical devices. However, there are currently no convenient and standardised methods for evaluating their metal ion release and antimicrobial efficacy. This work discusses analytical techniques and the proposed mechanisms of action while highlighting recent advances in film, membrane, and coating technologies. By addressing the current limitations, microporous materials can revolutionise antimicrobial approaches, offering enhanced effectiveness and long-term sustainability.

Research progress on antibacterial applications of metal-organic frameworks and their biomacromolecule composites

With the extensive use of antibiotics, resulting in increasingly serious problems of bacterial resistance, antimicrobial therapy has become a global concern. Metal-organic frameworks (MOFs) are low-density porous coordination materials composed of metal ions and organic ligands, which can form composite materials with biomacromolecules such as proteins and polysaccharides. In recent years, MOFs and their derivatives have been widely used in the antibacterial field as efficient antibacterial agents. This review offers a detailed summary of the antibacterial applications of MOFs and their composites, and the different synthesis methods and antibacterial mechanisms of MOFs and MOF-based composites are briefly introduced. Finally, the challenges and prospects of MOFs-based antibacterial materials in the rapidly developing medical field were briefly discussed. We hope this review will provide new strategies for the medical application of MOFs-based antibacterial materials.

Yolk-shell composite optical sensors with chiral L-histidine/Rhodamine 6G for high-sensitivity "turn-on" detection of L-proline

Chirality is a ubiquitous phenomenon in nature and has attracted wide attention in the biomedicine, pharmaceutics and biosensing research fields. Enantiomeric recognition of chiral compounds, especially chiral drugs and chiral amino acids, is important for human health and nutrition. In this work, through the encapsulation of L-His&R6G (L-His = L-Histidine; R6G = Rhodamine 6G) into MOF@MOF framework ZIF-67@ZIF-8, composited material L-His&R6G@ZIF-67@ZIF-8 can be obtained. Additionally, through the etching process, a unique yolk-shell ZIF-8 chiral composite optical sensors L-His&R6G@ZIF-8 (1) can be successfully prepared. Photo-luminescent (PL) experiment also reveals that 1 can highly sensitively detect L-Proline (L-Pro) through the "turn-on" detection strategy (KBH = 1.22 × 104 M-1 and detection limit 1.9 μM). Further yolk-shell L-His&R6G@ZIF-8-based fabricate flexible mixed-matrix membranes has been prepared using doctor-blading technique, which show significant fluorescence enhancement effect under ultraviolet lamp. This work also provides the unique example of preparing chiral yolk-shell framework composite sensors, which have broad application in chiral sensing area.