Efficient electronic communication-driven photoinduced charge-separation in 2-ureido-4[1H]-pyrimidinone quadruple hydrogen-bonded N,N-dimethylaniline-anthracene assemblies

Fast skin healing chitosan/PEO hydrogels: In vitro and in vivo studies

Due to its outstanding qualities, particularly when it takes the shape of hydrogels, chitosan is a well-known biological macromolecule with many applications. When chitosan hydrogels are modified with other polymers, the desirable function as skin regeneration hydrogels is compromised; nevertheless, the mechanical properties can be improved, which is crucial for commercialization. In this study, for the first time, bimetallic zinc silver metal-organic frameworks (ZAg MOF) loaded with ascorbic acid were added to chitosan/polyethylene oxide (PEO) based interpenetrating polymer network (IPN) hydrogels that were crosslinked with biotin to improve their antimicrobial activity, mechanical characteristics, and sustainable treatment of wounds. Significant changes in the microstructure, hydrophilicity level, and mechanical properties were noticed. Ascorbic acid release patterns were upregulated in an acidic environment pH (5.5) that mimics the initial wound pH. Impressive cell viability (98 %), antimicrobial properties, and almost full skin healing in a short time were achieved for the non-replaceable chitosan/PEO developed hydrogels. Enhancing the wound healing of the treated animals using the prepared CS/PEO hydrogel dressing was found to be a result of the inhibition of dermal inflammation via decreasing IL-1β, suppressing ECM degradation (MMP9), stimulating proliferation through upregulation of TGF-β and increasing ECM synthesis as it elevates collagen 1 and α-SMA contents. The findings support the implementation of developed hydrogels as antimicrobial hydrogels dressing for fast skin regeneration.

Recent Advances in Silver Nanoparticles Containing Nanofibers for Chronic Wound Management

Infections are the primary cause of death from burns and diabetic wounds. The clinical difficulty of treating wound infections with conventional antibiotics has progressively increased and reached a critical level, necessitating a paradigm change for enhanced chronic wound care. The most prevalent bacterium linked with these infections is Staphylococcus aureus, and the advent of community-associated methicillin-resistant Staphylococcus aureus has posed a substantial therapeutic challenge. Most existing wound dressings are ineffective and suffer from constraints such as insufficient antibacterial activity, toxicity, failure to supply enough moisture to the wound, and poor mechanical performance. Using ineffective wound dressings might prolong the healing process of a wound. To meet this requirement, nanoscale scaffolds with their desirable qualities, which include the potential to distribute bioactive agents, a large surface area, enhanced mechanical capabilities, the ability to imitate the extracellular matrix (ECM), and high porosity, have attracted considerable interest. The incorporation of nanoparticles into nanofiber scaffolds constitutes a novel approach to “nanoparticle dressing” that has acquired significant popularity for wound healing. Due to their remarkable antibacterial capabilities, silver nanoparticles are attractive materials for wound healing. This review focuses on the therapeutic applications of nanofiber wound dressings containing Ag-NPs and their potential to revolutionize wound healing.

Ultrafast Vibrational Energy Transfer through the Covalent Bond and Intra- and Intermolecular Hydrogen Bonds in a Supramolecular Dimer by Two-Dimensional Infrared Spectroscopy

In this work, the structural fluctuations and vibrational energy transfer dynamics in a supramolecular homodimer model, which is composed of 2-(9-anthracene)ureido-6-(1-undecyl)-4[1H]-pyrimidinone (UPAn) with quadruple intermolecular and single intramolecular hydrogen bonds (HBs), have been examined using ultrafast two-dimensional infrared (2D IR) and steady-state IR spectroscopies. A less structurally fluctuating intermolecular HB is found between the pyrimidinone C═O and ureido N-H groups. However, a larger structurally fluctuating intramolecular HB is suggested by the equilibrium and dynamical line-shape measurements of the ureido C═O stretch. Further, dynamical time-dependent 2D IR diagonal and off-diagonal signals show that intra- and intermolecular vibrational energy transfer processes occur on the picosecond timescale, where the latter is more efficient due to intermolecular hydrogen bonding interaction and through-space interaction.