Oleksandr Solodovnyk

Niobium‐based MXenes exhibitefficient near‐infrared (NIR) absorption but remain underexplored for in vivo cancer therapy. In this study, we investigated Nb ₄ C ₃ T _x MXene as an NIR‐II photothermal therapy (PTT) sensitizer for melanoma. Both in vitro and in vivo experiments were performed using Nb ₄ C ₃ T _x in combination with pulsed 1064 nm laser irradiation. Tumor growth, histological changes, and spatial localization of MXene were assessed to evaluate therapeutic efficacy and safety. Nb ₄ C ₃ T _x significantly enhanced tumor suppression under pulsed NIR‐II irradiation, inducing extensive destruction of melanoma cells while sparing surrounding tissue. Histological analysis revealed macrophage‐mediated uptake and clearance of MXene, with no evidence of persistent accumulation in tumor remnants or visceral organs. Pulsed laser irradiation provided precise and rapid heating, improving treatment accuracy and minimizing collateral damage. However, complete tumor eradication was not achieved, likely owing to limited light penetration in bulky tumors and the nontargeted distribution of pristine MXene. Our study demonstrates the feasibility and safety of Nb ₄ C ₃ T _x MXene‐assisted PTT in vivo, providing the first experimental evidence of its therapeutic potential in melanoma treatment. These findings establish Nb ₄ C ₃ T _x as a promising platform for pulsed laser–mediated PTT, while highlighting the need for targeted functionalization and treatment optimization to achieve selective tumor ablation.

MXenes are well-known as highly biocompatible two-dimensional nanomaterials with a wide range of biomedical applications, including antibacterial strategies. However, the coexistence of high biocompatibility and reported strong antibacterial effects presents a fundamental contradiction that requires critical evaluation. In this study, we systematically investigated the antibacterial properties of pure Ti₃C₂T _x , Nb₂CT _x , V₂CT _x , and Ti₃CNT _x MXene nanosheets of varying flake sizes using multiple in vitro assays and an in vivo wound model. High-resolution structural and chemical characterizations confirmed the use of high-quality, minimally oxidized MXene samples with well-defined surface terminations. Despite using multiple evaluation methods, including disk diffusion, broth microdilution, time-kill kinetics, ROS quantification, and electron microscopy, no significant antibacterial effects were observed at subtoxic concentrations. Furthermore, neither reactive oxygen species-mediated damage nor the hypothesized “nano-knife” mechanical disruption mechanism could be confirmed. This suggests that the previous observations of antibacterial properties resulted from incomplete removal of etching products or partial oxidation of MXene nanosheets. In contrast, we demonstrate that MXene-assisted photothermal therapy (PTT) under near-infrared laser irradiation offers highly effective and selective bacterial ablation. Ti₃C₂T _x MXene exhibited strong photothermal performance, achieving complete bacterial killing in vitro and significant wound healing efficacy in an in vivo rat model. Targeted PTT using antibody-functionalized MXene nanosheets enabled the eradication of Escherichia coli while sparing nontarget bacteria. These findings suggest that while intrinsic antibacterial properties of pristine MXenes are limited, their biocompatibility and photothermal responsiveness make them promising platforms for next-generation, externally triggered antibacterial therapies.

MXenes are well-known as highly biocompatible two-dimensional nanomaterials with a wide range of biomedical applications, including antibacterial strategies. However, the coexistence of high biocompatibility and reported strong antibacterial effects presents a fundamental contradiction that requires critical evaluation. In this study, we systematically investigated the antibacterial properties of pure Ti3C2Tx, Nb2CTx, V2CTx, and Ti3CNTx MXenes of varying flake sizes using multiple in vitro assays and an in vivo wound model. High-resolution structural and chemical characterizations confirmed the use of high-quality, minimally oxidized MXene samples with well-defined surface terminations. Despite using multiple evaluation methods, including disk diffusion, broth microdilution, time-kill kinetics, ROS quantification, and electron microscopy, no significant antibacterial effects were observed at sub-toxic concentrations. Furthermore, neither reactive oxygen species-mediated damage nor the hypothesized “nano-knife” mechanical disruption mechanism could be confirmed. This suggests that the previous observations of antibacterial properties resulted from incomplete removal of etching products or partial oxidation of MXenes. In contrast, we demonstrate that MXene-assisted photothermal therapy (PTT) under near-infrared laser irradiation offers highly effective and selective bacterial ablation. Ti3C2Tx MXene exhibited strong photothermal performance, achieving complete bacterial killing in vitro and significant wound healing efficacy in an in vivo murine model. Targeted PTT using antibody-functionalized MXenes enabled the eradication of E. coli while sparing non-target bacteria. These findings suggest that while intrinsic antibacterial properties of pristine MXenes are limited, their biocompatibility and photothermal responsiveness make them promising platforms for next-generation, externally triggered antibacterial therapies.

Introduction. Age-related impairment of bone healing is a growing clinical concern. While the role of trace elements in bone metabolism is well recognized, their effect on cancellous bone regeneration in elderly organisms remains poorly understood. Our study contributes a valuable foundation for understanding how excess exposure to specific trace elements – namely zinc (Zn), manganese (Mn), copper (Cu), lead (Pb), and chromium (Cr) – affects bone regeneration. Through a comparative histological and ultrastructural analysis of fracture healing in control and microelement-overload groups, we aim to elucidate the mechanisms by which trace elements modulate bone repair, angiogenesis, and osteogenesis in aged organisms. Methods. Our study was focused on comparing the course of cancellous bone healing under physiological conditions and trace element overconsumption in senile rats using histological and scanning electron microscopy analysis. Results. The results showed cancellous bone healing of control group followed a time-dependent sequence of inflammation, granulation tissue formation, fibroreticular remodeling, and coarse woven bone deposition. In contrast, the trace element overconsuption group exhibited delayed and disorganized reparative osteogenesis, marked by delay tissue formation, prolonged inflammatory features, and substantial cartilaginous tissue formation by day 21. Reduced vascular density in MeG animals suggested impaired angiogenesis, further contributing to compromised regeneration. Conclusions. Trace element overconsumption alters the normal trajectory of cancellous bone healing in senile rats, inducing a shift toward endochondral ossification and impairing vascularization. These findings underscore the critical influence of microelement balance on skeletal repair in aging organisms.

Innovative therapies are urgently needed to combat cancer. Thermal ablation of tumor cells is a promising minimally invasive treatment option. Infrared light can penetrate human tissues and reach superficial malignancies. MXenes are a class of 2D materials that consist of carbides/nitrides of transition metals. The transverse surface plasmons of MXenes allow for efficient light absorption and light-to-heat conversion, making MXenes promising agents for photothermal therapy (PTT). To date, near-infrared (NIR) light lasers have been used in PTT studies explicitly in a continuous mode. We hypothesized that pulsed NIR lasers have certain advantages for the development of tailored PTT treatment targeting tumor cells. The pulsed lasers offer a wide range of controllable parameters, such as power density, duration of pulses, pulse frequency, and so on. Consequently, they can lower the total energy applied and enable the ablation of tumor cells while sparing adjacent healthy tissues. We show for the first time that a pulsed 1064 nm laser could be employed for selective ablation of cells loaded with Ti₃C₂T_x MXene. We demonstrate both low toxicity and good biocompatibility of this MXene in vitro, as well as a favorable safety profile based on the experiments in vivo. Furthermore, we analyze the interaction of MXene with cells in several cell lines and discuss possible artifacts of commonly used cellular metabolic assays in experiments with MXenes. Overall, these studies provide a basis for the development of efficient and safe protocols for minimally invasive therapies for certain tumors.

Nowadays there is a need for new generation of biodegradable implants, which should be able to stimulate the healing responses of injured tissues at the molecular level. Magnesium alloys attract great attention as perspective bone implants due to their biocompatibility, physical properties and ability to degrade completely under physiological conditions. The main purpose of this research was assessment of in vitro corrosion and surface morphology after short term in vivo implantation of Mg based implant covered by hydroxyapatite (HA). Mg alloys with the addition of Zr (0.65%), Al (1.85%) and Nd (1.25%) were used. In our work, we propose dipping method for hydroxyapatite coatings formation which has been shown to reduce the corrosion rate of magnesium implants in vivo. Simulated body fluid (SBF; pH 7.4) with ion concentrations approximately equal to those of human blood plasma resembling physiological conditions and citrate buffer with pH 5—simulating inflammation were selected as modelling environments for in vitro degradation test. The rod samples were implanted into the tibia bone of rats and after 1 day and 5 days of implantation were taken out to observe cells adhesion on surface samples. SEM was used to assess surface morphology after in vitro and in vivo tests. SBF solution causes some cracks on the surface of HA coatings, while citrate solution at pH 2 caused complete dissolving of the coating. The HA coating favoured cell adhesion and rapid fibrous tissue formation.

Basing on the literature data, negative tendency for the modern tuberculosis course was substantiated. The main causes of conservative treatment failures for chronic and aged forms of tuberculosis were shown. The data concerning the surgical treatment character change for pulmonary tuberculosis, from resection toward thoracoplasty, were adduced. The authors consider extrapleural thoracoplasty as an alternative to pulmonectomy.