Biomedical materials (Bristol, England)最新文献

Titanium (Ti), characterized by its exceptional mechanical properties, commendable corrosion resistance and biocompatibility, has emerged as the principal functional materials for implants in biomedical and clinical applications. However, the Ti-6Al-4V (TC4ELI) alloy has cytotoxicity risks, whereas the strength of the existing industrially pure titanium TA4 is marginally inadequate and will significantly limit the scenarios of medical implants. Herein, we prepared ultrafine-grained industrial-grade pure titanium TA4 and titanium alloy TC4ELI via the equal channel angular pressing method, in which the TA4-1 sample has ultrahigh strength of 1.1 GPa and elongation of 26%. In comparison with the micrometer-crystalline Ti-based materials, it showed a 35% reduction in wear depth and more than 10% reduction in wear volume, while the difference in the corrosion potential of the simulated body fluids was not significant (only ∼20 mV). XRD, electron backscatter diffraction, and transmission electron microscope characterization confirms that their superior strengths are mainly due to grain refinement strengthening.

Scaffolds are of great interest in tissue engineering associated with regenerative medicine owing to their ability to mimic biological structures and provide a support for a new tissue formation. Several techniques are used to produce biological scaffolds; among them, far-field electrospinning (FFES) process is widely used due to its versatility in producing promising structures similar to native tissues owing to the electrospun nanofibers. On the other hand, near-field electrospinning (NFES) has been investigated due to the possibility of creating scaffolds with suitable architecture for its use in specific biological tissues. Thus, we investigated the potential of the electrospun scaffolds prepared using both techniques FFES and NFES, with tailored properties to mimic bone tissue native matrix and enhance the cell response. We produced scaffolds with the piezoelectric PVDF-TrFE combined with BaTiO3 nanoparticles. Hence, the properties of both scaffolds were evaluated in terms of crystallinity and cell behavior such as adhesion, proliferation and cell viability. Microstructure properties showed good thermal stability, similar crystallinity (~ 65%) and a β-phase content of ~40% for both scaffolds. For biological tests, MG-63 osteoblast-like cells were used, and for NFES scaffolds, we noted that the proliferation and cell alignment followed the fiber pattern and create a bridge between adjacent fibers. In contrast, cells spread and proliferated randomly on the surface of the FFES scaffold. Despite the differences in cell behavior, both scaffolds showed good biocompatibility in terms of functional scaffolds with suitable characteristics for use in the area of tissue regeneration.

Medical antibacterial textiles play a vital role in tackling the issue of bacterial infection. Traditional surgical sutures face significant challenges due to wound infection caused by bacteria and breakage and scars caused by poor suture strength. Therefore, a new antibacterial and high-strength suture preparation strategy with wide clinical applicability was highly desired. In this study, a biodegradable quaternary ammonium salt (QAS)/polylactic acid (PLA) core-spun yarn with excellent antibacterial and mechanical properties was prepared by conjugated electrospinning technology combined with the braiding process. The antibacterial test results revealed the best overall performance of the PLA micro/nanofiber core-spun yarn with 0.3 wt% QAS antibacterial agent. The antibacterial rate against Escherichia coli and Staphylococcus aureus was 94.49% and 94.00%, respectively, which could effectively solve the problem of wound infection caused by bacteria. In addition, we used the diamond-braided structure to address the poor strength and fragility of the traditional suture strength. The braiding angle of 30° and 45° could effectively enhance the mechanical properties of the yarn, and the breaking strength was also in line with the industry standard. The study proposed that the degradable QAS/PLA micro/nanofiber core-spun yarn, due to its excellent antibacterial and mechanical properties, could find application in medical protection. This provided a new avenue for research into new antibacterial surgical sutures.

Ultraviolet-assisted Direct Ink Writing（UV-DIW）, an extrusion-based additive manufacturing technology, has emerged as a prominent 3D printing technique and is currently an important topic in bone tissue engineering research. This study focused on the printability of double-network (DN) bioink (Nano-hydroxyapatite/Polyethylene glycol diacrylate(nHA/PEGDA)). Next, we search for the optimal UV-DIW printing parameters for the scaffold formed by nHA-PEGDA. In the end, we developed a scaffold that has outstanding structural integrity and can repair bone defects. Achieving high-quality UV-DIW printing can be challenging due to a variety of factors (slurry solid content, rheology, printing conditions, etc.).At present, there are limited reports about precise parameter configurations for UV-DIW printing. We optimised the solid composition of the slurry by varying the quantities of nHA and PEGDA, establishing the maximum solid content (40 wt%) permissible for scaffold shaping. Consequently, we examined the influence of several factors (nozzle diameter, air pressure, and printing rate) on the surface morphology of the scaffolds and determined the ideal conditions to attain scaffolds with superior printing accuracy. The findings demonstrate excellent controllability, repeatability, and precision of the entire printing process. Finally, we evaluated the scaffolds that most effectively fulfilled the requirements for bone regeneration by examining their surface morphology and mechanical characteristics. The experimental findings indicate that nHA-PEGDA scaffolds fulfill the compressive strength requirements for bone tissue and possess promising applications in bone regeneration. This study demonstrates that the nHA-PEGDA bioink possesses significant potential as a scaffold material for bone tissue regeneration, exhibiting exceptional shape integrity and mechanical capabilities. The study found the optimal parameters for bio-3D printers and gave UV-DIW an exact data reference for making the nHA-PEGDA scaffold. In addition, it is a useful guide for 3D printing biomaterial scaffolds.

Different morphologies of graphitic carbon nitride (g-C3N4), including bulk g C- 3N4 (B-CN), ultrathin nanosheet g-C3N4(N CN), and porous g-C- 3N4 (P-CN) were synthesized through a facile one-step approach. They were then employed as efficient photocatalysts under visible light to degrade methylene blue (MB) and deactivate Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) bacteria. The synthesized powders were characterized using various industry standard techniques and Field Emission Scanning Electron Microscopy (FE-SEM) analysis successfully represented the various morphologies of g-C3N4. Furthermore, the antibacterial activities of synthesized samples were examined, and the results revealed that B- CN, N CN, and P-CN powders could eliminate around 64%, 82%, and 99% of- E. coli under visible light irradiation and about 30%, 56, and 67% in dark conditions. On the other hand, the bacterial reduction rate of S. aureus was approximately 61%, 74%, and 99% for B-CN, N-CN, and P-CN powders under visible light irradiation and about 38%, 60%, and 77% in dark conditions. The SEM analysis revealed that P-CN caused E. coli and S. aureus bacteria to rupture, completely separating their internal contents from the cell membrane. g-C3N4 photocatalytic antibacterial agents can be utilized as a unique potential solution for nosocomial infection management. .

The combining of therapeutic agents with electrospun nanofibers boosts their regeneration potential; therefore, Researchers have increasingly turned towards the development of electrospun nanofiber scaffolds to encapsulate or surface-adsorb biological payloads, such as cytokines, exosomes, peptides, nucleic acids, and enzymes. Due to their high surface-to-volume ratio, ease of manufacturing, and drug-loading capacity, electrospun nanofibers are hopeful in tissue engineering and scaffold fabrication. Electrospun multilayer scaffolds offer a promising construction for preserving the integrity and bioactivity of therapeutic factors while permitting the controlled and prolonged release of biomolecules into the environment. The present study aimed to evaluate the mechanism of controlled release of electrospun exosomes from a three-layer nanofiber scaffold and its effect on the expression of DDR2 and VEGF genes in fibroblast cells in vitro. Adipose-Derived Mesenchymal Stem Cells (AD-MSCs) were obtained and isolated from liposuction surgery samples, and their intrinsic nature was confirmed using flow cytometry. After the exosomes were separated from the cell supernatant, their size, shape, and index markers were identified. The cytotoxicity, biocompatibility, and mechanical characteristics of scaffolds were evaluated. The qRT-PCR results showed the upregulation of DDR2 and VEGF genes in the three-layer scaffold containing the exosomes was 2.04 and 1.47-fold compared to the control group. The design and construction of multi-layered electrospun nanofibers loaded with bioactive substances and favorable mechanical and biological properties for controlled and sustained release will be promising and effective scaffolds for therapeutic purposes.

In the treatment of joints, mucosa, and full-thickness wounds, traditional implant surgery presents not only inconvenience but also a significant risk of wound infection. Additionally, the pharmaceutical application of mangiferin(MGF) has been severely restricted due to its poor water solubility. In this study, we reported the synthesis and characterization of sodium-mangiferin (MGF-Na(S)) using the salt formation method. This novel compound exhibits a solubility of up to 80 mg/mL, which is remarkably 800 times higher than that of MGF. Subsequently, MGF-Na(S) was combined with water to synthesize an injectable sodium-mangiferin homopolymeric hydrogel (MGF-Na(HG)). The hydrogel was further characterized, and its wound-healing properties were investigated. The results indicated that MGF-Na(HG) effectively extends the residence time of therapeutic agents on the wound surface, thereby enhancing wound healing. Moreover, this hydrogel forms a protective gel layer that prevents exogenous bacterial reinfection, providing an optimal environment for wound healing. Furthermore, the hydrogel demonstrated excellent self-healing and injectable properties, highlighting its potential for managing postoperative wounds. The successful utilization of this injectable, self-healing, and antibacterial MGF-Na(HG) in wound healing offers a novel approach for the application of MGF.

Bioprinting has the potential to revolutionize tissue engineering and regenerative medicine, offering innovative solutions for complex medical challenges and addressing unmet clinical needs. However, traditionalin vitrobioprinting techniques face significant limitations, including difficulties in fabricating and implanting scaffolds with irregular shapes, as well as limited accessibility for rapid clinical application. To overcome these challenges,in-situbioprinting has emerged as a groundbreaking approach that enables the direct deposition of cells, biomaterials, and bioactive factors onto damaged organs or tissues, eliminating the need for pre-fabricated 3D constructs. This method promises a personalized, patient-specific approach to treatment, aligning well with the principles of precision medicine. The success ofin-situbioprinting largely depends on the advancement of bioinks, which are essential for maintaining cell viability and supporting tissue development. Recent innovations in hand-held bioprinting devices and robotic arms have further enhanced the flexibility ofin-situbioprinting, making it applicable to various tissue types, such as skin, hair, muscle, bone, cartilage, and composite tissues. This review examinesin-situbioprinting techniques, the development of smart, multifunctional bioinks, and their essential properties for promoting cell viability and tissue growth. It highlights the versatility and recent advancements inin-situbioprinting methods and their applications in regenerating a wide range of tissues and organs. Furthermore, it addresses the key challenges that must be overcome for broader clinical adoption and propose strategies to advance these technologies toward mainstream medical practice.

Due to the limited self-regeneration capacity of bone, medical interventions is often required for large segmental bone defects. In this study, the application of porous titanium alloy (Ti6Al4V) scaffold in bone defect repair was investigated. Owing to its excellent mechanical properties and biocompatibility, Ti6Al4V is a preferred choice for orthopedic implants. To reduce the negative impact of its high elastic modulus on bone tissue, 3D printing technology was utilized to manufacture porous structures to approximate the elastic modulus of human bone, reducing the stress shielding phenomenon. In addition, electrochemical deposition technology was employed to deposit CeO2 nanoparticles (CNPs) onto the scaffold surface, aiming to improve its biological activity. According to the experimental findings, adding CNPs significantly enhanced the scaffold osteogenic capability. In vitro experiments on proliferation and expression of osteogenic markers verified its biological activity, while in vivo experiments further confirmed its potential to promote bone regeneration. Through detailed material characterization and biological evaluation, this study demonstrated the application prospect of 3D printed porous Ti6Al4V scaffold combined with CNPs, providing a new idea for the clinical repair of bone defects. .

Injectable nanocomposite hydrogels (NC hydrogels) have the potential to be used for minimally invasive local drug delivery. In particular, pH-sensitive injectable NC hydrogels can be used in cancer treatment to deliver high doses of anticancer drugs to the target site in cancer tissue without damaging healthy tissue. Recent studies have shown that in addition to stimuli-responsive delivery of anticancer drugs to cancer cells, oxygen delivery to the hypoxic environment of cancer tissue can lead to advanced effects, as hypoxia and an acidic pH are common characteristics of cancer tissue. However, few studies have investigated the effects of simultaneous administration of oxygen (O2) and pH-dependent anticancer drugs via injectable NC hydrogels on the viability of healthy and cancer cells under normoxic and hypoxic conditions. In this context, we describe the synthesis of injectable NC hydrogels composed of pH-responsive nanomaterials carrying oxygen and anticancer drugs. Our system provides sustained O2 release and pH-responsive sustained release of anticancer drugs for 15 and 30 days, respectively. Moreover, O2 delivery and/or simultaneous delivery of O2 and anticancer drug resulted in higher cell survival of healthy fibroblast cells than malignant Colo-818 cells under hypoxic conditions (1% O2) after 7 days of incubation. .