Biomedical materials (Bristol, England)最新文献

Binder jetting is a promising technology in the additive manufacturing of bone implants, particularly for printing brittle bioceramics that are susceptible to thermal residual stresses. However, challenges in this field include low strength and undesirable size changes due to post-sintering treatments, as well as the absence of necessary organic matter like Glycosaminoglycans, citric acid, etc. To address these issues, a novel approach was introduced using citric acid (CA) as a post-processing agent to enhance the mechanical performance of green samples and add organic matter, with boric acid (BA) as a control. A hydroxyapatite (HA) based powder mixed with 25 wt.% high-viscosity polyvinyl alcohol (PVA) was prepared and printed using a self-made printer with deionized water as the binder. The post-processing effects were analyzed in terms of mechanical properties and microstructure. The application of 5 wt.% CA solution increased the thickness of the PVA film between HA particles by 320.0%, leading to an increase in compressive strength (7.37 ± 0.28 MPa) and modulus (102.81 ± 6.74 MPa) by 840.7% and 1571.3%, respectively, achieving the mechanical standards for human trabecular bone. This work presents a simple and rapid room-temperature post-processing strategy for enhancing the mechanical properties of bone implants produced by binder jetting additive manufacturing.

In tissue engineering, collaboration among experts from different fields is needed to design appropriate cell scaffolds and the required three-dimensional environment. Osteochondral tissue engineering is particularly challenging due to the need to provide scaffolds that imitate structural and compositional differences between two neighboring tissues, articular cartilage and bone, and the required complex biophysical environments for cultivating such scaffolds. This work focuses on two key objectives: first, to develop bilayered osteochondral scaffolds based on gellan gum and bioactive glass and, second, to create a biomimetic environment for scaffold characterization by designing and utilizing novel dual-medium cultivation bioreactor chambers. Basic chemical engineering principles were utilized to help achieve both aims. First, a simple heat transport model based on one-dimensional conduction was applied as a guideline for bilayer scaffold preparation, leading to the formation of a gelatinous upper part and a macroporous lower part with a thin, well-integrated interfacial zone. Second, a novel cultivation chamber was developed to be used in a dynamic compression bioreactor to provide possibilities for flow of two different media, such as chondrogenic and osteogenic. These chambers were utilized for characterization of the novel scaffolds with regard to bioactivity and stability under dynamic compression and fluid perfusion over 14 d, while flow distribution under different conditions was analyzed by a tracer method and residence time distribution analysis.

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 imposed by commercial vascular prostheses. A comprehensive investigation of these engineered scaffolds in bioreactor is deemed essential as a prerequisite before any in vivo experimentation in order to get information regarding their behavior under physiological conditions and predict the biological activities they will possess. This study focuses on an innovative electrospun scaffold made of poly(caprolactone) and poly(glycerol sebacate), integrating quercetin, able to modulate inflammation, and gelatin, necessary to reduce permeability. A custom-made bioreactor was used to assess the performances of the scaffolds maintained under different pressure regimes, covering the human physiological pressure range. As results, the 3D microfibrous architecture was notably influenced by the release of bioactives, maintaining the adequate properties needed for the in vivo regeneration and scaffolds showed mechanical properties similar to human native artery. Release of gelatin was adequate to avoid blood leakage and useful to make the material porous during the testing period, whereas the amount of released quercetin was useful to counteract the post-surgery inflammation. This study showcases the successful validation of an engineered scaffold in a bioreactor, enabling to consider it as a promising candidate for vascular substitutes in in vivo applications. 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. .

The corrosion of magnesium (Mg)-based bioabsorbable implanting devices is influenced by implantation environment which dynamically changes by biological response including wound healing. Understanding the corrosion mechanisms along the healing process is essential for the development of Mg-based devices. In this study, a hematoma model was created in a rat femur to analyze Mg corrosion with hematoma in the early stage of implantation. Pure Mg specimen (99.9%,ϕ1.2 × 6 mm) was implanted in rat femur under either hematoma or non-hematoma conditions. After a designated period of implantation, the specimens were collected and weighed. The insoluble salts formed on the specimen surfaces were analyzed using scanning electron microscopy, energy-dispersive x-ray spectroscopy, and Raman spectroscopy on days 1, 3, and 7. The results indicate that hematomas promote Mg corrosion and change the insoluble salt precipitation. The weight loss of the hematoma group (27.31 ± 5.91 µg mm^-2) was significantly larger than that of the non-hematoma group (14.77 ± 3.28 µg mm^-2) on day 7. In the non-hematoma group, carbonate and phosphate were detected even on day 1, but the only latter was detected on day 7. In the hematoma group, hydroxide was detected on day 1, followed by the formation of carbonate and phosphate on days 3 and 7. The obtained results suggest the hypoxic and acidic microenvironment in hematomas accelerates the Mg corrosion immediately after implantation, and the subsequent hematoma resorption process leads to the formation of phosphate and carbonate with organic molecules. This study revealed the risk of hematomas as an acceleration factor of the corrosion of Mg-based devices leading to the early implant failure. It is important to consider this risk in the design of Mg-based devices and to optimize surgical procedures controlling hemorrhage at implantation and reducing unexpected bleeding after surgery.

Curcumin is a natural polyphenolic compound extracted from turmeric with antibacterial, antioxidant, antitumor, preventive and therapeutic neurological disorders and a variety of bioactivities, which is widely used in the field of food and medicine. However, the drawbacks of curcumin such as poor aqueous solubility and stability have limited the practical application of curcumin. To overcome these defects and enhance its functional properties, various nanoscale systems (liposomes, polymer nanoparticles, protein nanoparticles, solid lipid nanoparticles, metal nanoparticles, etc) have been extensively employed for curcumin encapsulation and delivery. Despite the rapid development of curcumin nanoformulations, there is a lack of comprehensive reviews on their preparation and properties. This review provides an overview of the construction of curcumin nano-delivery systems, mechanisms of action, nanocarrier preparation methods and the applications of curcumin nanocarriers in the food and pharmaceutical fields to provide a theoretical basis and technological support for the efficient bio-utilization, product development and early clinical application of curcumin.

During the healing process after intra-nasal surgery, the growth and repair of damaged tissues can result in the development of postoperative adhesions. Various techniques have been devised to minimize the occurrence of postoperative adhesions which include insertion of stents in the middle meatus, application of removable nasal packing, and utilizing biodegradable materials with antiadhesive properties. This study assesses the efficacy of two sodium hyaluronate (SH)-based freeze-dried hydrogel composites in preventing postoperative nasal adhesions, comparing them with commonly used biodegradable materials in nasal surgery. The freeze-dried hydrogels, sodium hyaluronate and collagen 1(SH-COL1) and sodium hyaluronate, carboxymethyl cellulose, and collagen 1 (SH-CMC-COL1), were evaluated for their ability to reduce bleeding time, promote wound healing, and minimize fibrous tissue formation. Results showed that SH-CMC-COL1 significantly reduced bleeding time compared to both biodegradable polyurethane foam and SH-COL1. Both SH-COL1 and SH-CMC-COL1 exhibited enhanced wound healing effects, as indicated by significantly greater wound size reduction after two weeks compared to the control. Histological analyses revealed significant differences in re-epithelialization and blood vessel count among all tested materials, suggesting variable initial wound tissue response. Although all treatment groups had more epithelial growth, with X-SCC having higher blood vessel count at 7 d post treatment, all treatment groups did not differ in all histomorphometric parameters by day 14. However, the long-term application of SH-COL1 demonstrated a notable advantage in reducing nasal adhesion formation compared to all other tested materials. This indicates the potential of SH-based hydrogels, particularly SH-COL1, in mitigating postoperative complications associated with nasal surgery. These findings underscore the versatility and efficacy of SH-based freeze-dried hydrogel composites for the management of short-term and long-term nasal bleeding with an anti-adhesion effect. Further research is warranted to optimize their clinical use, particularly in understanding the inflammatory factors influencing tissue adhesions and assessing material performance under conditions mimicking clinical settings. Such insights will be crucial for refining therapeutic approaches and optimizing biomaterial design, ultimately improving patient outcomes in nasal surgery.

Soft-tissue injuries affecting muscles, nerves, vasculature, tendons, and ligaments often diminish the quality of life due to pain, loss of function, and financial burdens. Both natural healing and surgical interventions can result in scarring, which potentially may impede functional recovery and lead to persistent pain. Scar tissue, characterized by a highly disorganized fibrotic extracellular matrix, may serve as a physical barrier to regeneration and drug delivery. While approaches such as drugs, biomaterials, cells, external stimulation, and other physical forces show promise in mitigating scarring and promoting regenerative healing, their implementation remains limited and challenging. Ultrasound, laser, electrical, and magnetic forms of external stimulation have been utilized to promote soft tissue as well as neural tissue regeneration. After stimulation, neural tissues experience increased proliferation of Schwann cells, secretion of neurotropic factors, production of myelin, and growth of vasculature, all aimed at supporting axon regeneration and innervation. Yet, the outcomes of healing vary depending on the pathophysiology of the damaged nerve, the timing of stimulation following injury, and the specific parameters of stimulation employed. Increased treatment intensity and duration have been noted to hinder the healing process by inducing tissue damage. These stimulation modalities, either alone or in combination with nerve guidance conduits and scaffolds, have been demonstrated to promote healing. However, the literature currently lacks a detailed understanding of the stimulation parameters used for nerve healing applications. In this article, we aim to address this gap by summarizing existing reports and providing an overview of stimulation parameters alongside their associated healing outcomes.

The main reasons for the difficulty in curing and high recurrence rate of glioblastoma multiforme (GBM) include: 1. The difficulty of chemotherapy drugs in penetrating the blood-brain barrier (BBB) to target tumor cells; 2. The presence of glioma stem cells (GSCs) leading to chemotherapy resistance. Therefore, breaking through the limitations of the BBB and overcoming the drug resistance caused by GSCs are the main strategies to address this problem. This study presents our results on the development of lactoferrin (Lf)/CD133 antibody conjugated nanostructured lipid carriers (Lf/CD133-NLCS) for simultaneously targeting BBB and GSCs. Temozolomide (TMZ) loaded Lf/CD133-NLCS (Lf/CD133-NLCS-TMZ) exhibited high-efficiencyin vitroanti-tumor effects toward malignant glioma cells (U87-MG) and GSCs, while demonstrating no significant toxicity to normal cells at concentrations lower than 200 μg ml^-1. The results of thein vitrotargeting GBM study revealed a notably higher cellular uptake of Lf/CD133-NLCS-TMZ in U87-MG cells and GSCs in comparison to Lf/CD133 unconjugated counterpart (NLCS-TMZ). In addition, increased BBB permeability were confirmed for Lf/CD133-NLCS-TMZ compared to NLCS-TMZ bothin vitroandin vivo. Taking together, Lf/CD133-NLCS-TMZ show great potential for dual targeting of BBB and GSCs, as well as GBM therapy based on this strategy.

The role of blood clots in tissue repair has been identified for a long time; however, its participation in the integration between implants and host tissues has attracted attention only in recent years. In this work, a mesoporous silica thin film (MSTF) with either vertical or parallel orientation was deposited on titania nanotubes surface, resulting in superhydrophilic nanoporous surfaces. A proteomic analysis of blood plasma adsorption revealed that the MSTF coating could significantly increase the abundance of acidic proteins and the adsorption of coagulation factors (XII and XI), with the help of cations (Na⁺, Ca²⁺) binding. As a result, both the activation of platelets and the formation of blood clots were significantly enhanced on the MSTF surface with more condensed fibrin networks. The two classical growth factors of platelets-derived growth factors-AB and transformed growth factors-βwere enriched in blood clots from the MSTF surface, which accounted for robust osteogenesis bothin vitroandin vivo. This study demonstrates that MSTF may be a promising coating to enhance osteogenesis by modulating blood clot formation.