Marzena Fandzloch

Defect-engineered UiO-66 serves as a multifunctional platform for controlled release of biologically active compounds and, after Eu ³⁺ incorporation, luminescent Fe ³⁺ sensing.

A novel core-shell hybrid material composed of bioactive glass (BG) nanoparticles and the metal-organic framework (MOF) MIL-100(Fe) (Fe₃O(H₂O)₂OH(BTC)₂·nH₂O, BTC: 1,3,5-benzenetricarboxylate) was synthesized using a layer-by-layer strategy. The formation of the MIL-100(Fe) shell on the BG core was directly confirmed by high-resolution transmission electron microscopy, which revealed a continuous MOF layer with an average thickness of 6.1 ± 0.9 nm. Complementary characterization by infrared spectroscopy, X-ray powder diffraction, X-ray photoelectron spectroscopy, N₂ sorption, and synchrotron-based X-ray absorption spectroscopy (XAS) confirmed the coexistence of MIL-100(Fe) and BG components and their structural integrity within the hybrid material. Notably, for the first time, a synchrotron-based technique (XAS) was used to characterize the MOF@BG system, providing unique insight into its local coordination environment and structural evolution. The hybrid material demonstrated favorable cytocompatibility in a long-term (21-day) assay on mouse osteoblast precursor cells (MC3T3) and human dermal fibroblasts (HDF). At the same time, it did not induce ex vivo hemolysis at concentrations up to 1000 μg/mL. The induction of osteogenic differentiation in MC3T3 cells in the presence of MIL-100(Fe)@BG was confirmed by early osteogenic markers, including alkaline phosphatase (ALP) activity and alizarin red staining (ARS). Bioactivity studies in Dulbecco's phosphate-buffered saline (DPBS) and simulated body fluid (SBF) revealed rapid formation of nanohydroxyapatite, beginning within the first hours of incubation. Importantly, under physiological conditions, the MIL-100(Fe) shell undergoes a controlled structural transformation, yielding highly dispersed nanoscale Fe₂O₃ particles. These nanoparticles induce the production of reactive oxygen species (ROS) and contribute to antibacterial activity, thereby inhibiting E. coli and S. aureus without the need for external antimicrobial agents. The combination of bioactivity, osteogenic potential, hemocompatibility, and intrinsic antibacterial functionality positions MIL-100(Fe)@BG as a promising multifunctional platform for bone regeneration and infection control.

The first example of a Eu( iii )-based coordination polymer supported on a (bio)carrier: EuBTC@HA (where H ₃ BTC = 1,3,5-benzenetricarboxylic acid and HA stands for hydroxyapatite) for dual sensing of Fe ³⁺ ions and ofloxacin.

The standard clinical management of osteomyelitis involves prolonged antibiotic therapy, which frequently necessitates the excision of infected tissues. However, the efficacy of such treatments is increasingly compromised by the rise of antibiotic-resistant pathogens, underscoring an urgent need for innovative approaches. This study introduces a novel composite material designed to offer dual functionality: robust antimicrobial activity and promotion of bone regeneration. The composite integrates biocompatible hydroxyapatite nanoparticles (HA) with a titanium(IV)-metal-organic framework, MIL-125(Ti)-NH₂, impregnated with gentamicin (GM). The solvothermally synthesized MIL-125-NH₂@HA composite demonstrates high cytocompatibility, as evidenced by assays using osteoblasts (U2-OS) and fibroblasts (L929), alongside an absence of hemolytic activity at concentrations of up to 1000 μg/mL. Importantly, the introduction of GM into the composite significantly amplifies its antibacterial efficacy against Staphylococcus aureus and Pseudomonas aeruginosa. Additionally, nanoindentation assessments reveal enhanced mechanical properties of the MIL-125-NH₂@HA composite, indicating the superior elastic performance relative to unmodified HA. The findings of this research are poised to generate significant interest in the development of metal-organic framework (MOF)-based composites for antimicrobial implant applications, presenting a promising avenue for addressing the challenges posed by antibiotic resistance in bone infections.

Multifunctional materials that combine antimicrobial properties with the ability to stimulate bone formation are needed to overcome the problem of infected bone defects. As a novel approach, a new composite based on bioactive glass nanoparticles in a simple system of SiO₂–CaO (BG) coated with NH₄[Cu₃(μ₃-OH)(μ₃-4-carboxypyrazolato)₃] (Cu-MOF) with additionally anchored silver nanoparticles (AgNPs) was proposed. Ag@Cu-MOF@BG obtained by the spin coating approach in the form of a disc was characterized using PXRD, ATR-FTIR, XPS, ICP-OES, and TEM. Importantly, the material retained its bioactivity, although ion exchange in the bioactive glass administered as a disc is limited. Hydroxyapatite (HA) formation was identified in TEM images after 7 days of immersion of the composite in a physiological-like buffer (pH 7.4, 37 °C). The Cu and Ag contents of Ag@Cu-MOF@BG were as low as 0.013 and 0.018 wt% respectively, but the slow release of the AgNPs ensured its antibacterial nature. Ag@Cu-MOF@BG exhibited antibacterial activity against all tested bacteria (E. coli, S. aureus, P. aeruginosa, and K. pneumoniae) with the diameter of the inhibition zones of their growth between 8 and 10 mm and the reduction index determined to be ≥3. Moreover, the biocompatibility of the new composite has been demonstrated, as shown by cell culture assays with human dermal fibroblasts (HDFs). The results from the migration test also proved that the HDF cell's phenotypic properties were not changed, and the cell adhesion and migration ability were the same as in control indirect assays.

A novel composite based on biocompatible hydroxyapatite (HA) nanoparticles and Cu-HKUST-1 (Cu-HKUST-1@HA) has been prepared following a layer-by-layer strategy. Cu-HKUST-1 was carefully selected from a group of four Cu-based metal-organic frameworks as the material with the most promising antimicrobial activity. The formation of a colloidal Cu-HKUST-1 layer on HA nanoparticles was confirmed by various techniques, e.g., infrared spectroscopy, powder X-ray diffraction, N₂ sorption, transmission electron microscopy imaging, electron paramagnetic resonance, and X-ray absorption spectroscopy. Importantly, such a Cu-HKUST-1 layer significantly improved the nanomechanical properties of the composite, with Young's modulus equal to that of human cortical bone (13.76 GPa). At the same time, Cu-HKUST-1@HA has maintained the negative zeta potential (-16.3 mV in pH 7.4) and revealed biocompatibility toward human dermal fibroblasts up to a concentration of 1000 μg/mL, without inducing ex vivo hemolysis. Chemical stability studies of the composite over 21 days in a buffer-simulated physiological fluid allowed a detailed understanding of the transformations that the Cu-HKUST-1@HA undergoes over time. Finally, it has been confirmed that the Cu-HKUST-1 layer provides antibacterial properties to HA, and the synergism reached in this way makes it promising for bone tissue regeneration.

Four highly bioactive glasses in a binary SiO₂–CaO system are prepared following a sol−gel method using Ca(OH)₂ as a calcium precursor. In the synthesis of glass according to the modified Stöber method, Ca(OH)₂ suspended in polyethylene glycol allows the elimination of the presence of calcite and the increase of ammonia concentration causes formation of spherical particles with different sizes in the range of 26–266 nm. The relation among the size and properties, including bioactivity, of the glass particles is evaluated. New glasses that vary in composition (10–25 wt% CaO), porosity (15–113 m² g⁻¹), and hydroxyl groups content greatly enhance the formation process of hydroxyapatite (HA) in simulated physiological fluids. For all glasses, superior apatite‐mineralization ability in time as short as 2 h in the physiological‐like buffer is achieved, thus exceeding the bioactivity of the known bioactive glasses, including 45S5 glass (Bioglass). The assessment of the safety and toxicity profile of the obtained glasses is verified in a wide range of concentrations (1–1000 µg mL⁻¹) against human dermal fibroblasts and MC3T3 mouse osteoblast precursors, but also to human erythrocytes by determining hemocompatibility. Two glasses of different sizes, 73 and 266 nm, are promising and warrant further research.

Ascorbic acid (AA) is an important biomolecule, the deficiency or maladjustment of which is associated with the symptoms of many diseases (e.g., cardiovascular disease or cancer). Therefore, there is a need to develop a fluorescent probe capable of detecting AA in aqueous media. Here, we report the synthesis, structural, and spectroscopic characterization (by means of, e.g., XRD, XPS, IR and Raman spectroscopy, TG, SEM, and EDS analyses), as well as the photoluminescent properties of a metal–organic framework (MOF) based on Cu²⁺ and Eu³⁺ ions. The ion-exchange process of the extraframework cation in anionic Cu-based MOF is proposed as an appropriate strategy to obtain a new material with a nondisturbed structure and a sensitivity to interaction with AA. Accordingly, a novel Eu[Cu₃(μ₃-OH)(μ₃-4-carboxypyrazolato)₃] compound for the selective optical detection of AA with a short detection time of 5 min is described.