Cu-vitamin B3 donut-like MOFs incorporated into TEMPO-oxidized bacterial cellulose nanofibers for wound healing.

In this study, a novel multifunctional nanocomposite wound dressing was developed, consisting of TEMPO-oxidized bacterial cellulose (TOBC) nanofibers functionalized with donut-like copper-based metal-organic frameworks (CuVB3 MOFs). These CuVB3 MOFs were constructed using copper nodes linked by vitamin B3 molecules, resulting in a copper nicotinate crystal structure as confirmed by X-ray diffraction. Electron microscopy confirmed the presence of donut-like microstructures with uniform element distribution in the synthesized MOFs. Through the incorporation of CuVB3 MOFs into the TOBC nanofibers, innovative TOBC-CuVB3 nanocomposites were created. Biocompatibility testing using the MTT assay demonstrated enhanced cell viability of over 115% for the TOBC-CuVB3 nanocomposite. Acridine Orange staining revealed a ratio of 88-92% live cells on the wound dressings. Furthermore, fibroblast cells cultured on TOBC-CuVB3 exhibited expanded morphologies with long filopodia. The agar diffusion method exhibited improved antibacterial activity against both Gram-positive and Gram-negative bacterial strains, correlating with increased CuVB3 concentration in the samples. In vitro cellular scratch assays demonstrated excellent wound healing potential, with a closure rate of over 98% for wounds treated with the TOBC-CuVB3 nanocomposite. These findings underscore the synergistic effects of copper, vitamin B3, and TOBC nanofibers in the wound healing process.

A Novel Silver-Based Metal-Organic Framework Incorporated into Nanofibrous Chitosan Coatings for Bone Tissue Implants.

In this work, new multi-layer nanocomposite coatings comprised of chitosan (CS) nanofibers functionalized using an innovative silver-based metal-organic framework (SOF) were developed. The SOFs were produced via a facile process using green and environmental-friendly materials. The CS-SOF nanocomposites were coated on hierarchical oxide (HO) layers fabricated on titanium substrates by an innovative two-step etching process. X-ray diffraction revealed fruitful production of the SOF NPs and their stable crystalline structure within the nanocomposite coatings. Energy-dispersive x-ray spectroscopy approved uniform SOFs distribution in the CS-SOF nanocomposites. Atomic force microscopy indicated more than 700% increased nanoscale roughness for the treated surfaces compared to the bare sample. In vitro MTT assay revealed proper cell viabilities on the samples, however, high SOFs concentration led to less biocompatibility. All coatings demonstrated positive cell proliferation rates up to 45% after 72 h. Antibacterial studies showed significant inhibition zones against Escherichia coli and Staphylococcus aureus bacteria with 100-200% effective antibacterial activities. Electron microscopy exhibited excellent cell-implant integration for the CS-SOF nanocomposite surfaces due to the attached cells with expanded morphologies and long filopodia. The prepared coatings showed high apatite formation capability and bone bioactivity.

Synergistic Wound Healing by Novel Ag@ZIF-8 Nanostructures.

In this paper, novel zeolitic imidazolate framework-8 (ZIF-8) functionalized with Ag (Ag@ZIF-8) nanoparticles were synthesized through a green, facile and environmental-friendly process for wound dressing applications. X-ray diffraction revealed that the ZIF-8 and Ag@ZIF-8 were successfully synthesized by green solvents at ambient temperature. Field-emission scanning electron microscopy indicated a homogeneous porous blend of âˆ¼30 nm chitosan/bacterial cellulose (CS/BC) nanofibers embedded with âˆ¼80-110 nm nanoparticles of the ZIF-8 and Ag@ZIF-8. Transmission electron microscopy revealed the Ag@ZIF-8 nanostructures consist of ZIF-8 cores that are covered by 5-20 nm Ag nanoparticles. MTT assay indicated excellent cell viability values of âˆ¼115 and 109% for the CS/BC nanocomposites reinforced by ZIF-8 and Ag@ZIF-8 nanoparticles, respectively. The Ag-containing wound dressings showed 52-300% of effective antibacterial activities. Animal studies demonstrated excellent healing for the wound treated by CS/BC-25%Ag@ZIF-8 nanocomposite with âˆ¼91% of wound closure after 14 days of treatment. Hematoxylin and eosin (H&E) staining revealed successful healing and tissue regeneration for the wounds treated using the CS/BC-Ag@ZIF-8 nanocomposites. This kind of nanocomposites with synergistic antimicrobial and bioactivity properties can be a promising candidate for regenerative medicine.

Bioinspired TiO2/chitosan/HA coatings on Ti surfaces: biomedical improvement by intermediate hierarchical films.

The most common reasons for hard-tissue implant failure are structural loosening and prosthetic infections. Hence, in this study, to overcome the first problem, different bioinspired coatings, including dual acid-etched, anodic TiO2nanotubes array, anodic hierarchical titanium oxide (HO), micro- and nanostructured hydroxyapatite (HA) layers, and HA/chitosan (HA/CS) nanocomposite, were applied to the titanium alloy surfaces. X-ray diffraction and FTIR analysis demonstrated that thein situHA/CS nanocomposite formed successfully. The MTT assay showed that all samples had excellent cell viability, with cell proliferation rates ranging from 120% to 150% after 10 days. The HO coating demonstrated superhydrophilicity (θ≈ 0°) and increased the wettability of the metallic Ti surface by more than 120%. The friction coefficient of all fabricated surfaces was within the range of natural bone's mechanical behavior. The intermediate HO layer increased the adhesion strength of the HA/CS coating by more than 60%. The HO layer caused the mechanical stability of HA/CS during the 1000 m of friction test. The microhardness of HA/CS (22.5 HV) and micro-HA (25.5 HV) coatings was comparable to that of human bone. A mechanism for improved adhesion strength of HA/CS coatings by intermediate oxide layer was proposed.