Biomedical materials (Bristol, England)最新文献

The inert surface of titanium (Ti) leads to inadequate osseointegration and bacterial infection, which are critical factors contributing to the failure of Ti implants. Micro-arc oxidation (MAO) technology enables the formation of a biocompatible porous TiO₂coating on Ti surfaces, offering advantages such as a simple fabrication process, strong adhesion to the substrate, and the ability to incorporate functional ions (e.g. Ag⁺, Cu²⁺, Sr²⁺). This modification significantly enhances cellular adhesion and osteogenic activity. However, the TiO₂produced via MAO exhibits a wide bandgap (3.2 eV), responding primarily to ultraviolet light, which results in low photothermal conversion efficiency in the near-infrared (NIR) region with greater tissue penetration, thereby limiting its application in photothermal therapy (PTT). This study was based on Sr²⁺-doped TiO₂coating, and its NIR photothermal efficiency was improved through surface modification with a metal-polyphenol network (MPN). Additionally,ϵ-poly-L-lysine (EPL) antimicrobial peptides were grafted onto the surface to establish a synergistic photothermal-chemical antibacterial system. Experimental results demonstrated that the TiO₂-MPN-EPL composite coating exhibited high-efficiency photothermal conversion under 808 nm laser irradiation, with the synergistic action of EPL providing targeted membrane disruption of bacteria. This system achieved a high bactericidal rate againstStaphylococcus aureusandEscherichia coliwhile mitigating the thermal damage risks associated with standalone PTT. Furthermore, it promoted the proliferation of MC3T3-E1 osteoblasts.

Hydrogels, as three-dimensional (3D) hydrophilic polymer networks, have gained widespread attention in tissue engineering (TE) due to their high-water content, porosity, biocompatibility, and structural similarity to the native extracellular matrix. Injectable andin situforming hydrogels offer additional advantages by enabling minimally invasive delivery directly to injury sites, reducing patient discomfort, and improving clinical accessibility. Among these, tyramine (Tyr)-modified hydrogels have emerged as a promising class of biomaterials, combining enhanced biocompatibility, bioactivity, and mechanical properties through the incorporation of phenolic groups. This functionalization enables enzymatic and light-mediated cross-linking under mild physiological conditions, providing precise control over hydrogel stiffness, degradation, and cell-interacting properties. This review comprehensively covers recent advances in the synthesis, modification, and cross-linking strategies of Tyr-conjugated polymers, particularly enzymatic methods mediated by horseradish peroxidase (HRP) and hydrogen peroxide (H₂O₂), as well as light-mediated methods, and their impact on the properties of hydrogels. It also further explores the broad applications of Tyr-modified hydrogels in TE, including bone and cartilage regeneration, wound healing, vascular and cardiac repair, and 3D bioprinting. Finally, it discusses current challenges and future perspectives for Tyr-modified hydrogels in regenerative medicine.

The employment of metal nanoparticles for biomedical applications is gaining visibility as a result of their excellent properties. Niobium oxide (Nb₂O₅) possesses interesting physicochemical properties that can be modified for its use in prosthetic coatings. However, there are only a limited number of studies in the literature concerning its characterization as a pure powder, its surface modification and their cytotoxicity. Therefore, the purpose of this study was to evaluate nine different Nb₂O₅samples synthesized using the microwave technique, each with a different surfactant. x-ray diffraction results indicated that all samples were amorphous, and the addition of surfactants did not seem to cause any alterations, as indicated by Raman and FTIR. Scanning electron microscopy (SEM) images revealed that the particles tended to form aggregates; modification of parameters such as surface area and acid sites was also observed, with pure Nb₂O₅having the highest area (230.4 m²g^-1) and NbSDS5 having the highest total acidity (3141 µmol g^-1). We assessed the cytotoxicity in sheep's erythrocytes and the Zebrafish Liver (ZF-L) cell line. Pure Nb₂O₅exhibited high cytotoxicity at 10 mg ml^-1in red blood cells with an erythrocyte survival rate of 15%. The MTT assay that revealed that NbCA1 showed only 27.1% cell viability, while NbSDS1 was able to increase cell proliferation (101.1%) even at a lower pH. Compounds were also able to interfere with the intrinsic coagulation pathway, with several samples exceeding the clotting time (>120 s). Nb ions leaching to the medium does not seem to directly affect cytotoxicity. Pearson's correlation does not indicate a direct relationship between surface area, acid sites, and cytotoxicity assays.

Vascular tissue engineering endeavors to design, fabricate, and validate biodegradable and bioabsorbable small-diameter vascular scaffolds engineered with bioactive molecules, capable of meeting the challenges posed by commercial vascular prostheses. A comprehensive investigation of these engineered scaffolds in a bioreactor (BR) is deemed essential as a prerequisite before anyin vivoexperimentation in order to gather information regarding their behavior under physiological conditions and predict the biological activities they may exhibit. This study focuses on an innovative electrospun scaffold made of poly(caprolactone) and poly(glycerol sebacate), integrating quercetin (Q), which is able to modulate inflammation, and gelatin (G), which is necessary to reduce permeability. A custom-made BR was used to assess the performance of the scaffolds maintained under different pressure regimes, covering the human physiological pressure range. As a result, the 3D microfibrous architecture of the scaffolds was notably influenced by the release of bioactive molecules, while retaining the properties required forin vivoregeneration. Furthermore, the scaffolds exhibited mechanical properties comparable to those of native human arteries. The release of Q was effective in counteracting post-surgical inflammation, whereas the amount of released G was adequate to avoid blood leakage and useful to make the material porous during the testing period. This study showcases the successful validation of an engineered scaffold in a BR, supporting its potential as a promising candidate for vascular substitutes inin vivoapplications. Our approach represents a significant leap forward in the field of vascular tissue engineering, offering a multifaceted solution to the complex challenges associated with small-diameter vascular prostheses.

Cervical spondylosis and spinal injuries are increasing public health concerns, often associated with prolonged 'text neck' posture, sedentary lifestyles, and trauma. Artificial cervical disc replacement (ACDR) offers a treatment option. However, current prostheses are limited by narrow eligibility criteria, risks of ectopic ossification that may result in spinal fusion, and potential issues with subsidence or displacement. This study presents a novel, porous-structured prosthesis designed for implantation after bone resection, expanding ACDR applicability by enabling complete lesion removal. Developed through finite element analysis and fabricated via laser powder bed fusion using Ti-6Al-4V extra low interstitial alloy, the prosthesis is optimized for both biomechanical and biological compatibility. Tests indicate that the porous structure supports bone ingrowth, with mechanical properties closely matching those of human bone, effectively mitigating stress shielding. The gradient mechanical properties enhance integration with autologous bone, reducing postoperative complications. This work establishes a foundation for using porous bionic implants in cervical spine therapy, with broader implications for orthopedic and biomedical applications requiring high biomechanical compatibility.

Arteriovenous (AV) shunts are critical conduits for patients with end-stage renal disease undergoing hemodialysis. Desired properties of next-generation AV graft materials include artery-like mechanics, clinically feasible manufacturing processes, and a bioactive interface that facilitates rapid and deep infiltration of neighboring cells to support tissue regeneration. These requirements inspired the design, fabrication, and post-processing of our constructs. In terms of material design, we evaluated the performance of three microfiber graft materials composed of a hydrophobic polymer and photo-clickable, 4-arm thiolated polyethylene glycol-norbornene (PEG-NB). The materials included two coaxially nanostructured fiber designs, each featuring a PEG-NB sheath and different cores-polycaprolactone (PCL) and PCL-co-lactic acid (PLCL), respectively-and a mixed composition created by directly blending the sheath and core solutions during electrospinning. For post-processing, the constructs were either air-dried or freeze-dried (FD). Surface morphology was assessed using scanning electron microscopy, while mechanical properties were characterized through tensile testing and dynamic mechanical analysis. Subcutaneous implants were evaluated at 1, 4, and 16 weeks using histological, immunofluorescent, and multiphoton microscopy analyses to examine cellular distribution, material structure, and tissue remodeling. Results showed that the freeze-drying post-processing method enhanced overall porosity, stiffness, and ultimate tensile strength. Among all tested conditions, the FD core-sheath structure with PCL most closely matched the mechanical properties of native vessels. Using PLCL as a core material increased degradation and cell infiltration during the first month of subcutaneous studies. Ultimately, graft strength, porosity, and bioactivity were effectively modulated by the choice of core material and post-processing method. These findings provide insights into tailoring electrospun PEG-NB hybrid constructs as candidate AV shunt grafts, highlighting opportunities to balance mechanical performance, degradation, and bioactivity for end-stage renal disease patients requiring durable hemodialysis access.

Limited organ availability and transplantation risks have driven the development of tissue engineering approaches. This study developed and characterized crosslinked collagen biomaterial inks extracted from calf skin for three-dimensional bioprinting applications. Collagen was extracted using pepsin digestion and purified through dialysis. Biomaterial inks were prepared at 3%, 4%, and 5% (w/v) concentrations and crosslinked using genipin (1, 3, 5 mM) and riboflavin (1 mM) with UV-A activation. Optimal printing parameters were determined as 5% (w/v) collagen concentration with 0.26 mm nozzle diameter. Synchrotron FTIR spectroscopy confirmed successful crosslinking through characteristic peak shifts in amide regions. Mechanical testing revealed enhanced compressive strength: riboflavin-crosslinked scaffolds (1.5 ± 0.08 MPa) > genipin-crosslinked scaffolds (1.19 ± 0.12 MPa) > uncrosslinked scaffolds (0.66 ± 0.03 MPa). Cell viability assessments demonstrated that genipin crosslinking at 1 mM concentration significantly enhanced fibroblast viability (181.2 ± 29.32% compared to uncrosslinked controls), while higher concentrations exhibited cytotoxic effects. Riboflavin biocompatibility assessment was limited by methodological constraints due to spectral interference, preventing reliable comparative evaluation. These results demonstrate that genipin crosslinking successfully enhances both mechanical properties and biocompatibility at appropriate concentrations, while riboflavin crosslinking provides superior mechanical reinforcement but requires alternative biocompatibility assessment methods for comprehensive characterization.

Intervertebral disc herniation is a leading cause of chronic low back pain, where the avascular nature of the disc limits nutrient transport to resident cells, resulting in cellular dysfunction and matrix degeneration. Enhancing vascular perfusion at the region has therefore emerged as a promising strategy to support disc repair. In this context, the present study aimed to develop a biomimetic, mechanically stable nanofibrous annulus fibrosus (AF) patch capable of sustained nicardipine delivery, while simultaneously supporting mesenchymal stem cell (MSC) viability and chondrogenic differentiation. For this, aligned and random poly(ϵ-caprolactone)/gelatin (75:25) nanofibrous patches were fabricated, with the hypothesis that scaffold architecture would influence both drug release behavior and cellular response. The results showed that the aligned fibers exhibited larger pore size and increased surface hydrophilicity compared to randomly oriented fibers. Nicardipine was efficiently encapsulated and released in a sustained manner over 21 d, with an additional late-stage increase in drug diffusion in aligned scaffolds.In vitroassessment using MSCs confirmed cytocompatibility, and markedly improved cell viability on aligned scaffolds. Overall, the findings demonstrate the potential of aligned, nicardipine-loaded PCL-gelatin nanofibrous AF patches as a dual-function platform for localized drug delivery and AF regeneration following discectomy. Further evaluation using native AF cells and relevantin vivomodels will be essential to determine long-term efficacy and safety.

The clinical use of topical hemostatic agents has become increasingly widespread. While these agents primarily serve to control bleeding, their direct contact with bone and surrounding tissues raises concerns about biological compatibility and potential interference with bone healing and regeneration. Given their growing use in osseous surgical procedures, it is critical to characterize and compare the osteogenic properties of these materials. This study evaluated four commercially available gelatin-based hemostatic sponges: Hemospon®, Clinix®, Gelatamp®, and Octocolagen®, for their osteogenic potential. Leachables derived from each sponge were prepared according to ISO 10993-12:2021 guidelines and tested at 12.5% and 50% concentrations inin vitroassays using human osteoblastic populations. Assessed parameters included metabolic activity, proliferation, osteogenic gene expression, alkaline phosphatase (ALP) activity, and extracellular matrix production. Additionally, intact sponges were directly applied to bone defects in anex vivoorganotypic bone culture model, enabling the tissue characterization within a physiologically relevant environment. Results demonstrated marked material-dependent differences. Gelatamp® significantly enhanced osteogenic gene expression, ALP activity, and matrix productionin vitro, and promoted mature collagen depositionex vivo. Hemospon® also showed favorable, though more limited, effects. Octocolagen® exhibited a neutral biologically profile, while Clinix® consistently impaired osteoblastic activity, gene expression, and extracellular matrix formation in both models. These findings demonstrate that gelatin-based hemostatic agents are not biologically equivalent. Material composition and processing influence their regenerative performance, underscoring the need for informed selection when used in bone-contact surgical applications.

Infected wound healing environments present dual challenges of microbial colonization and sustained oxidative stress, critically impairing patient outcomes. Developing advanced dressings capable of concurrent broad-spectrum antimicrobial action and redox homeostasis restoration remains an urgent clinical priority. Here, we engineered a multifunctional porcine small intestinal submucosa extracellular matrix dressing (i.e.SISTP) integrated with AI-screened antimicrobial peptides (AMPs) via tea polyphenol-mediated coordination. The CRRI6 hexapeptide (Arg-Trp-Trp-Arg-Trp-Phe) demonstrated prolonged release kinetics (>6 h) from the SISTP scaffold, achieving ⩾90% eradication ofE. coliandS. aureus. Radical scavenging assays confirmed SISTP's capacity to neutralize reactive oxygen species, whilein vivostudies revealed accelerated wound recovery in infected rat models through synergistic microbial clearance and oxidative stress mitigation. This study pioneers a bio-inspired strategy leveraging AI-optimized AMPs and polyphenol nanoengineering to address the multifactorial pathophysiology of chronic wounds.