The reliability of hard tissue engineering processes is crucial in a variety of application such as knee or hip joint replacement. For a successful integration of any implant, bone regeneration, osseointegration at the interface bone and implant as well as mitigating inflammatory events are essential aspects.

The objective of this work is to extend the biocompatibility, osteoconductivity and mechanical performance associated with a lifetime of biomaterials based on Titanium (Ti). The hypothesis state that the bioactivity of titanium alloy biomaterials can be increased by the addition of hydroxyapatite (HAp) and further boosted by porosity. Designing the gradient bio composite starting with preparation of materials mixture of Ti6Al4V powder, synthetized HAp powder (5 and 10% wt.) and a foaming agent cabroxymethylocelulose (CMC) (5 and 10% wt.) milled to a very uniform density by ZrO₂ ball miller. In a step next the powders mixtures were cascaded in a press die the first layer was Ti6Al4V+5%HAp+5%CMC and upper layer was Ti6Al4V+10%HAp+10%CMC, and next pressed by the cold isostatic pressing (CIP). Sintering of the composites was performed on a Yttria-stabilized zirconia plate with air channels in a vacuum furnace at 1300°C under Ar protective atmosphere. The results show high potential of this methodology for preparation of gradient structure, with lower layer hardness reaching 10GPa and elastic modulus 154 GPa and upper layer containing HAP and porosity reaching 10%.

The authors gratefully acknowledge financial support of the project “New Generation of Bioactive Laser Textured Ti/Hap Implants” under acronym “BiLaTex” carried out within M-ERA.NET 3 Call 2022 programme in the National Centre for Research and Development (ERA.NET3/2022/48/BiLaTex/2023).

Objective: To construct a multi-functional Ph-responsive hydrogel loaded with tannic acid, and explore its hemostatic function and promoting the repair of infected wounds, and initially explore the related mechanism of hydrogel promoting the repair of infected wounds. Method: Ph-responsive multifunctional hydrogels were composed of carboxymethyl chitosan (CMCS), Konjac oxide (OKGM) and tannic acid (TA). CMCS and OKGM were able to form Ph-responsive hydrogels with dynamic covalent bonds through Schiff base reaction. TA could enhance the antibacterial and mechanical properties of the hydrogels. The biocompatibility, blood compatibility and functional evaluation (antioxidant, antibacterial and hemostatic properties) of CMCS-OKGM@TA hydrogel were tested in vitro. Meanwhile, cellular function experiments related to wound healing were performed. The effects of CMCS-OKGM@TA hydrogel on inflammation regulation, vascularization and epithelialization of infected wounds in BALB/C mice were investigated under in vivo conditions. Transcriptomic sequencing was performed on skin tissues of infected wounds in mice to screen relevant pathways for mechanism study, providing new ideas for treatment of infected wounds. Results: Due to Schiff base reaction and hydrogen bonding, the compound could rapidly absorb liquid components, form gel and adhere to the tear, showing rapid liver hemostasis and tail hemostasis. The polyphenol groups of TA make the hydrogel have good antibacterial and scavenging properties of active oxygen free radicals. In addition, the hydrogel has good biocompatibility in vitro cytotoxicity, blood compatibility test and in vivo toxicity test. Finally, in vivo experiments showed that the hydrogel showed significant bacteriostasis and promoting wound healing. Conclusion: The multifunctional hydrogel has the ability of rapid hemostasis and bacteriostasis, and can be widely used in acute bleeding caused by trauma and as wound dressing to prevent bacterial infection.

Bone tissue engineering (BTE) has emerged as an option for creating new bone substitutes for application in bone tissue defects. The materials used for making the scaffolds have been based on FDA-approved synthetic polymers such as poly(ε-caprolactone) (PCL) and poly(lactic acid) (PLA) for their biodegradable, biocompatible, and mechanical properties. Moreover, one biopolymer, gelatin (Gt), has been used as a functional coating for its biological properties. In BTE, a combination of techniques has emerged for developing different microarchitectures that could imitate the extracellular matrix (ECM) of native bone. In this work, we try to combine electrospinning and 3D printing to create a bone scaffold with improved topological properties. We produce coaxial nanofibers (CNF) of PCL/Gt and PLA/Gt for coating circular porous 3D printing scaffolds using electrospinning. The characterization by SEM showed the fibrillar structures with interconnected pores with random alignment, and TEM indicated the formation of the core–shell structure. FTIR and thermal analysis showed the characteristic signals of each component and no apparent effect on the decomposition stages of each material, respectively. The biological characterization of the 3D scaffold coating showed improved adhesion in 24 h and good biocompatibility and bioactivity of human fetal osteoblasts over the 21 days of culture. In conclusion, our results showed that CNF-coated scaffolds achieve improved topological properties by functionalizing Gt-based coaxial electrospun nanofibers with potential use in BTE. The authors want to thank the financial support by CONAHCYT for the scholarship granted for the doctoral study of CETS with CVU 1009583 and the financial support given by the DGAPA-UNAM-PAPIIT IN202924, IN106624, and PAIP 5000-9222 projects.

This study explores the impact of α-tricalcium phosphate (α-TCP) on a poly-3-hydroxybutyrate (PHB) matrix via electrospinning (ES) to produce composite materials. The ES method allows for the production nonwoven fibrous materials with a high content of functional additives. The ES method ensures the uniform distribution of the additive, which is important for applications in regenerative medicine. Scanning electron microscopy (SEM) analysis of materials based on PHB-α-TCP shows a reduction in surface defects with the addition of α-TCP; however, at higher concentrations, larger inclusions appear. Additionally, morphology analysis indicates changes in fiber diameters and a decrease in surface density with the introduction of α-TCP, highlighting increased porosity and surface development.

Mechanical testing illustrates the deformation process of PHB-based nonwoven materials, with the rupture mechanism influenced by the presence of α-TCP. SEM images reveal the impact of α-TCP on the mechanism of the rupture, showcasing accumulations of the calcium source within the fibrous material.

Thermal properties were analyzed using differential scanning calorimetry. The impact of the additive on the thermal properties was insignificant during the first round of heating. The second round of heating showed a decrease in crystallinity, but X-ray diffraction analysis indicated changes in the supramolecular structure, with the crystallites themselves increasing in number.

The obtained materials were characterized by high porosity and surface development, which are crucial for effective tissue regeneration and restoration. The unique combination of properties in the PHB-α-TCP composite material holds promise for revolutionizing multiple industries, particularly those in the fields of regenerative medicine, dentistry, and environmental sustainability. However, further research is required to optimize the material's properties for specific applications, ensuring its safe and effective utilization.

Decellularized reproductive tissues have been used to generate biomaterials for several applications, not restricted to reproduction due to their enriched ECM and capacity to be modulated and applied for other tissues. This study aimed to produce and characterize grafts derived from decellularized uterine tissue to be used in tissue engineering approaches. Porcine uterine fragments (n=10) were decellularized in 1% SDS and 0.5% Triton X-100, followed by three cycles of ultrasonic bath. To evaluate the decellularization efficiency, HE and DAPI staining and total DNA quantification were performed. Histological analysis of ECM components was performed as well. SEM was used for ultrastructural characterization. For biomechanical characterization, native and decellularized samples were attached to a computerized mechanical testing machine and submitted to a traction charge. FTIR-ATR and Raman spectroscopy were used to perform a physical–chemical evaluation of ECM. For the cytocompatibility assay, 3T3 and canine yolk-sac-derived cells were cultured on the scaffolds for 10 days. DAPI and HE staining revealed absence of nuclei in decellularized samples; moreover, DNA quantification revealed a decrease of 95%. Regarding ultrastructure, 3D structure was maintained, conserving the original stratification and preserving thin and dense collagen bundles. Histological analyses showed that main ECM components remained preserved with a similar organization as found in the native tissue. Biomechanical results demonstrated significate difference only for the maximum pulling force between the groups, but there was no difference for maximum elongation and stiffness. Spectroscopic results also corroborated the structural findings, with no difference in the main analyzed band between the samples. In vitro assays revealed that cells were able to attach to the scaffolds, which allowed their survival and proliferation. Our data revealed that the decellularization was efficient, which preserved 3D structure, composition and biomechanical properties and presented satisfactory cytocompatibility, demonstrating the generated biomaterial can be used tissue-engineering applications.

In the past few decades, researchers have investigated Fe-based biodegradable alloys for various purposes such as biocompatibility, tissue healing control over degradation rate, and the shape memory effect (SME) for specific medical applications. Within this study, the authors proposed bifunctional Fe–Mn–Si-based alloys with additions of Ag and Cu as potential biodegradable materials with a SME. In vitro studies were conducted by immersing the samples in physiological solutions, Ringer’s and simulated body fluid (SBF), for different time intervals at 37 ℃. Corrosion rates were determined according to the mass loss, via cyclic and linear potentiometry, and electrochemical impedance spectroscopy (EIS). Microstructural analyses were performed using optical microscopy (OM) and scanning electron microscopy (SEM). Initial and post-immersion chemical analyses were performed using energy-dispersive spectroscopy (EDS), aiming to investigate the formation of salts, chlorides, and carbonates. The samples were subjected to dynamic mechanical analysis (DMA) and were evaluated before and after immersion at different applied frequencies. The surface morphology was examined using atomic force microscopy (AFM) for the initial samples and those subjected to DMA experiments. Fourier transform infrared spectroscopy (FT-IR) and nano-FTIR experiments were performed to identify and confirm the corrosion compounds formed on the surface. A generalized type of corrosion was identified, and an increase in mass was observed in the first 3-5 days due to the compounds formed due to metal–solution contact. A phase change in the solid state was observed using differential scanning calorimetry (DSC) during cooling, which was associated with a martensitic transformation. Its critical start temperature (M_s) was similar to the human body temperature, indicating that this material has potential for medical applications. The results suggested that a shape memory Fe-based biodegradable alloy has the potential to be used in the medical industry, with a suitable thermomechanical treatment to adjust the transition temperatures.

Introduction: After severe skin damage, the resulting scar usually contains dense extracellular matrix (ECM) fibers devoid of the hair follicle, which lack sensation and endocrine function as well as the flexibility of normal skin. The immune system plays a varying role in driving scar fibrosis or hair follicle regeneration upon different environmental stimuli. Recently, tissue regeneration mediated by immunoregulatory biomaterials is emerging as a prospective strategy in tissue engineering. The biomaterials ' topographical properties, such as pattern and diameter, play important roles in influencing cell activities and manipulating the related immune response during wound regeneration. As a result, there is an urgent need to explore the immunoregulatory mechanisms stimulating hair follicle regeneration in skin repair.

Methods: Here we present a method for skin wound regeneration using biodegradable aligned ECM scaffolds with different diameters: A300 (319 ± 100 nm), A600 (588±132nm), and A1000 (1048 ± 130 nm). Currently, development in single-cell RNA sequencing (scRNA-seq) and spatial transcriptomics (ST) has enabled the assessment of gene expression at spatial resolution, which has been applied to detect regional cellular communication. The large-scale wound healing model with implanted biomaterials provides an ideal method to understand and probe the role of the immune system in tissue regeneration.

Conclusions: We show that the implantation of A300 scaffolds accelerates wound coverage and enhances hair follicle neogenesis. Multimodal profiles highlight the potential role of regulatory T cells in mitigating tissue fibrous by suppressing excessive type 2 inflammation. We find that immunodeficient mice lacking mature T lymphocytes show the typical characteristic of tissue fibrous driven by type 2 macrophage inflammation, validating the potential therapeutic effect of the adaptive immune system activated by biomaterials. These findings contribute to our understanding of the coordination of immune systems in wound regeneration and facilitate the design of immunoregulatory biomaterials in the future.

Introduction

Spinal cord injury (SCI) is characterized by a primary SCI that is the consequence of a traumatic event, and by the subsequent inflammatory response, characterized by the activation of microglia/macrophages/astrocytes, that leads to an aggravation of the pathology and to neurodegeneration [1,2]. A possible therapeutic approach is represented by the possibility to modulate the inflammatory response through the release of drugs in the damaged zone selectively within different cell lines. Recent advances in polymer science and nanotechnologies showed increased interest for nanogels (NGs), a new class of colloidal systems that can be used as carriers to treat SCI.

Material and Methods

Nanogels were synthesized using polyethylene glycol (PEG) and polyethylenimine linear (PEI), after having functionalized PEI with a chromophore [3, 4]. This PEI functionalization was essential to constantly trace the nanogels during the biological assays. Many different coating strategies of the nanogels were analyzed; in fact, surface functionalization is essential to tune the characteristics and the biological behavior of the final system.

Results and discussion

Biological tests proved that functionalized nanogels were able to be selectively internalized in mouse microglia or astrocytes depending on their surface decoration, that their degradation promoted drug release, and that the use of anti-inflammatory molecules as a delivered drug were able to mitigate the pain state [5, 6]. Subsequent in vivo assays on diseased mice confirmed the result obtained in vitro and the potentiality of this kind of surface functionalization.

Conclusions

Nanogels are, for sure, effective devices in drug delivery, and here, we showed their potentialities as targeted drug delivery systems in SCI.

References

[1] Nature 2006, 7, 628.

[2] J. Control. Release. 2021, 330, 218.

[3] Coll. Surf. A. 2021, 614, 126164.

[4] Coll. Surf. A. 2023, 658, 130623.

[5] ACS Nano. 2020, 14, 360.

[6] ACS Nano. 2013, 7, 9881.

Introduction: Drug carriers made of magnetic nanoparticles (Fe3O4) have become increasingly popular. Iron nanoparticles possess distinct magnetic characteristics and can be transported to the desired location by the manipulation of a magnetic field. The medicine utilized in the study is doxorubicin. The issue with magnetic nanoparticles is in their tendency to form agglomerates when suspended in physiological solutions. To enhance particle stability and ensure safe application, it is necessary to apply a biocompatible polymer coating on the surface of the particles. Lysozyme is a biopolymer that possesses both anticancer and anti-inflammatory effects, which can stabilize nanoparticles and enhance therapeutical effects.

Methods: The magnetic nanoparticles were generated using three different methods: hydrothermal, annealing, and coprecipitation. The produced particles were analyzed by SEM, EDX analysis, FTIR spectroscopy, and BET. The surface charge of the nanoparticles was determined by measuring their zeta potential. The magnetic characteristics of the Fe3O4 particles were analyzed using a vibrating sample magnetometer. Experiments involving the loading and release of doxorubicin were conducted at various pH levels. In vitro cytotoxicity studies were conducted on the created nanosystem utilizing the Emt6 cell line and a healthy cell line.

Results: A comparative analysis of three distinct approaches for producing magnetic nanoparticles facilitated the determination of the most pertinent method for synthesizing Fe3O4 nanoparticles. The nanoparticles possess an ideal size of approximately 20 nm and exhibit magnetic properties of 68.4 emu/g. Additionally, they have greater specific surface area values of 62 m²/g. The particles obtained exhibited a significant capacity for loading doxorubicin. The incorporation of a lysozyme shell resulted in an extended duration of drug release from the created systems, in contrast to the uncoated nanoparticles.

Conclusions: Based on the findings of this study, the drug-loaded nanoparticles are suitable for cancer treatment and have potential for further in vivo investigations.

Introduction. Neuroblastoma is a type of cancer that develops in young children from immature nerve cells. Traditional treatments include surgery, chemotherapy, and radiotherapy. However, these treatments can cause significant side effects, especially in children, potentially affecting their development and long-term health. A novel approach of direct drug delivery to the tumor site has been proposed, using conductive polymer-based microspheres that carry the anti-cancer, anti-inflammatory, and antioxidant agent curcumin.

Methodology. Conducting polymer microspheres (CPMSs) were formed by the chemical polymerization of hydroxymethyl-3,4-ethylenedioxythiophene around polystyrene beads, with their further removal with the use of toluene. After incubation in a solution of curcumin, CPMSs were characterized by means of electron microscopy, UV-Vis spectroscopy, and infrared spectroscopy. Curcumin release was monitored under both static (no stimulation) and electrically triggered conditions. The cytotoxic effect of CPMSs was tested against a neuroblastoma (SH-SY5Y) cell line.

Results. Infrared spectroscopy confirmed the incorporation of curcumin within CPMSs, while release studies indicated a consistent, low-dose release of the drug, applicable to both electrically stimulated and spontaneous release scenarios. Cytotoxicity measurements proved the efficiency of curcumin-loaded CPMSs against a neuroblastoma cell line.

Conclusions. We showed that CPMSs possess the capacity to efficiently encapsulate and release curcumin, demonstrating suitable release kinetics. CPMSs proved to be effective in both spontaneous and electrically induced release scenarios. Future research will focus on assessing the biocompatibility of these carriers and evaluating their efficacy with various model drugs. The research suggests that CPMSs hold significant promise and practical utility as an innovative approach to anti-cancer treatment, especially for combating neuroblastoma.

Acknowledgements. The research was funded by the Silesian University of Technology as part of the 10th program financing project-oriented education – PBL (Excellence Initiative – Research University).