ObjectiveTo evaluate the bone repair efficacy of the new nano-hydroxyapatite (n-HA)/polyurethane (PU) composite scaffold in the treatment of chronic osteomyelitis in tibia.MethodsA novel levofloxacin@mesoporous silica microspheres (Lev@MSNs)/n-HA/PU was successfully synthesized. Its surface structure was observed by scanning electron microscopy (SEM). Fifty adult female New Zealand rabbits were randomly selected, and osteomyelitis was induced in the right tibia of the rabbit by injecting bacterial suspension (Staphylococcus aureus; 3×107 CFU/mL), which of the method was described by Norden. A total of 45 animals with the evidence of osteomyelitis were randomly divided into 4 groups, and the right medullary cavity of each animal was exposed. Animals in the blank control group (group A, n=9) were treated with exhaustive debridement only. The remaining animals were first treated by exhaustive debridement, and received implantations of 5 mg Lev@PMMA (group B, n=12), 1 mg Lev@MSNs/n-HA/PU (group C, n=12), and 5 mg Lev@MSNs/n-HA/PU (group D, n=12), respectively. At 12 weeks postoperatively, the right tibia of rabbits were observed by X-ray film, and then gross observation, methylene blue/acid fuchsin staining, and SEM observation of implant-bone interface, as well as biomechanical test (measuring the maximal compression force) were performed.ResultsX-ray films showed that the infection were severer than those of preoperation in group A, while the control of inflammation and bone healing of rabbits in group D were obviously better than those at preoperation. The gross observation showed extensive bone destruction in group A, a significant gap between bone tissue and the material in groups B and C, and close combination between bone tissue and the material in group D. The histology of the resected specimens showed that there was no obvious new bone formation around the materials in groups B and C, and there was abundant new bone formation around the periphery and along the voids of the materials and active bone remodeling in group D. The SEM observation of the bone-implant interface demonstrated that no new bone formation was observed at the bone-implant interface in groups B and C. However, bony connections and blurred boundaries were observed between the material and host bone tissue in group D. The biomechanical test showed the maximal compression force of groups B and D were significantly higher than that of groups A and C (P<0.05), but there was no significant difference between groups B and D (P>0.05).ConclusionThe novel synthetic composite Lev@MSNs/n-HA/PU exhibit good antibacterial activities, osteoconductivity, and biomechanical properties, and show great potential in the treatment of chronic osteomyelitis of rabbits.
ObjectiveTo summarize the research progress of suture augmentation (SA) in anterior cruciate ligament (ACL) reconstruction. MethodsA comprehensive review of recent literature about SA in ACL reconstruction at home and abroad was conducted. The efficacy of SA in ACL reconstruction was evaluated by examining the definition, biomechanics, and histological studies of SA, along with its clinical application status in ACL reconstruction. ResultsSA demonstrates significant advantages in enhancing the biomechanical stability of ACL grafts, reducing the risk of re-rupture, and accelerating postoperative recovery. Specifically, SA improves graft stiffness, ultimate failure strength, and cyclic stability, thereby diminishing the risk of early postoperative failure and joint instability. Histologically, it fosters remodeling and tendon-bone integration through early load-sharing mechanisms; however, stress shielding may interfere with natural remodeling processes, warranting further attention. Clinically, SA reduces graft failure rates and the need for revision surgeries, markedly improving knee joint stability and functional recovery in young patients. Nevertheless, its impact on graft maturation and potential complications remains controversial. ConclusionDespite the many advantages of SA in ACL reconstruction, future endeavors should focus on optimizing tensioning techniques, developing bioactive materials, and conducting large-scale randomized controlled trials to further elucidate its clinical value and scope of applicability, providing a more reliable solution for ACL reconstruction.
ObjectiveTo summarize the research progress of interfacial tissue engineering in rotator cuff repair.MethodsThe recent literature at home and abroad concerning interfacial tissue engineering in rotator cuff repair was analysed and summarized.ResultsInterfacial tissue engineering is to reconstruct complex and hierarchical interfacial tissues through a variety of methods to repair or regenerate damaged joints of different tissues. Interfacial tissue engineering in rotator cuff repair mainly includes seed cells, growth factors, biomaterials, oxygen concentration, and mechanical stimulation.ConclusionThe best strategy for rotator cuff healing and regeneration requires not only the use of biomaterials with gradient changes, but also the combination of seed cells, growth factors, and specific culture conditions (such as oxygen concentration and mechanical stimulation). However, the clinical transformation of the relevant treatment is still a very slow process.
Due to its special sequence structure, spider silk protein has unique physical and chemical properties, mechanical properties and excellent biological properties. With the expansion of the application value of spider silk in many fields as a functional material, progress has been made in the studies on the expression of recombinant spider silk proteins through many host systems by gene recombinant techniques. Recombinant spider silk proteins can be processed into high performance fibers, and a wide range of non-fibrous morphologies. Moreover, for their excellent biocompatibility and low immune response they are ideal for biomedical applications. Here we review the process and mechanism of preparation in vitro, chemistry and genetic engineering modification on recombinant spider silk protein.
ObjectiveTo explore the feasibility of three-dimensional (3D) bioprinted adipose-derived stem cells (ADSCs) combined with gelatin methacryloyl (GelMA) to construct tissue engineered cartilage.MethodsAdipose tissue voluntarily donated by liposuction patients was collected to isolate and culture human ADSCs (hADSCs). The third generation cells were mixed with GelMA hydrogel and photoinitiator to make biological ink. The hADSCs-GelMA composite scaffold was prepared by 3D bioprinting technology, and it was observed in general, and observed by scanning electron microscope after cultured for 1 day and chondrogenic induction culture for 14 days. After cultured for 1, 4, and 7 days, the composite scaffolds were taken for live/dead cell staining to observe cell survival rate; and cell counting kit 8 (CCK-8) method was used to detect cell proliferation. The composite scaffold samples cultured in cartilage induction for 14 days were taken as the experimental group, and the composite scaffolds cultured in complete medium for 14 days were used as the control group. Real-time fluorescent quantitative PCR (qRT-PCR) was performed to detect cartilage formation. The relative expression levels of the mRNA of cartilage matrix gene [(aggrecan, ACAN)], chondrogenic regulatory factor (SOX9), cartilage-specific gene [collagen type Ⅱ A1 (COLⅡA1)], and cartilage hypertrophy marker gene [collagen type ⅩA1 (COLⅩA1)] were detected. The 3D bioprinted hADSCs-GelMA composite scaffold (experimental group) and the blank GelMA hydrogel scaffold without cells (control group) cultured for 14 days of chondrogenesis were implanted into the subcutaneous pockets of the back of nude mice respectively, and the materials were taken after 4 weeks, and gross observation, Safranin O staining, Alcian blue staining, and collagen type Ⅱ immunohistochemical staining were performed to observe the cartilage formation in the composite scaffold.ResultsMacroscope and scanning electron microscope observations showed that the hADSCs-GelMA composite scaffolds had a stable and regular structure. The cell viability could be maintained at 80%-90% at 1, 4, and 7 days after printing, and the differences between different time points were significant (P<0.05). The results of CCK-8 experiment showed that the cells in the scaffold showed continuous proliferation after printing. After 14 days of chondrogenic induction and culture on the composite scaffold, the expressions of ACAN, SOX9, and COLⅡA1 were significantly up-regulated (P<0.05), the expression of COLⅩA1 was significantly down-regulated (P<0.05). The scaffold was taken out at 4 weeks after implantation. The structure of the scaffold was complete and clear. Histological and immunohistochemical results showed that cartilage matrix and collagen type Ⅱ were deposited, and there was cartilage lacuna formation, which confirmed the formation of cartilage tissue.ConclusionThe 3D bioprinted hADSCs-GelMA composite scaffold has a stable 3D structure and high cell viability, and can be induced differentiation into cartilage tissue, which can be used to construct tissue engineered cartilage in vivo and in vitro.
The presence of thrombus on the surface of blood-contacting biomaterials in clinical practice can significantly impact both the longevity of the biomaterials and the overall survival prognosis of patients. The administration of anticoagulant and antiplatelet medications may heighten the risk of systemic bleeding. Developing biomaterials with anti-thrombogenetic properties and enabling localized anti-thrombosis may offer a solution to these challenges. The development strategies for anti-thrombogenetic biomaterials can be categorized into three main approaches based on the mechanisms of thrombus formation on biomaterial surfaces: altering physical and chemical properties, designing coatings containing or releasing active substances, and promoting endothelialization. However, due to the intricate and interconnected nature of these mechanisms, biomaterials constructed using a single approach may not effectively prevent thrombus formation. The collaborative intervention of various mechanisms can facilitate the development of biomaterials with enhanced blood compatibility.
The study of viruses traditionally focused on their roles as infectious agents and as tools for understanding cell biology. Recently, however, with the development of structural biology, viruses have now been receiving particular attention in nanotechnology. By chemical methods or by gene modification, viruses have been functionalized as potential building blocks for several applications, such as drug/gene delivery vehicles, advanced vaccine vehicles, and special inorganic or organic nanomaterials. Here we highlight some of the recent progresses in the medical applications of viruses.
Ligaments are dense fibrous connective tissue that maintains joint stability through bone-to-bone connections. Ligament tears that due to sports injury or tissue aging usually require surgical intervention, and transplanting autologous, allogeneic, or artificial ligaments for reconstruction is the gold standard for treating such diseases in spite of many drawbacks. With the development of materialogy and manufacturing technology, engineered ligament tissue based on bioscaffold is expected to become a new substitute, which can lead to tissue regeneration by simulating the structure, composition, and biomechanical properties of natural tissue. This paper reviewed some recently published in vitro and animal researches focusing on ligament tissue engineering, then evaluated the properties and the effects on tissue repair and reconstruction of fiber structure scaffolds, multi-phase interface scaffolds and bio-derived scaffolds designed by bionic principle and made of different materials, manufacturing techniques and biological factors. Finally, summarization followed by the prospection for future development direction of biological scaffolds in ligament tissue engineering research is given.
Objective To review the osteoimmunomodulatory effects and related mechanisms of inorganic biomaterials in the process of bone repair. Methods A wide range of relevant domestic and foreign literature was reviewed, the characteristics of various inorganic biomaterials in the process of bone repair were summarized, and the osteoimmunomodulatory mechanism in the process of bone repair was discussed. Results Immune cells play a very important role in the dynamic balance of bone tissue. Inorganic biomaterials can directly regulate the immune cells in the body by changing their surface roughness, surface wettability, and other physical and chemical properties, constructing a suitable immune microenvironment, and then realizing dynamic regulation of bone repair. Conclusion Inorganic biomaterials are a class of biomaterials that are widely used in bone repair. Fully understanding the role of inorganic biomaterials in immunomodulation during bone repair will help to design novel bone immunomodulatory scaffolds for bone repair.
ObjectiveTo review the research progress and challenges of poly (L-lactic acid) (PLLA) membrane in preventing tendon adhesion. MethodsThe relevant literature at home and abroad in recent years was extensively searched, covering the mechanism of tendon adhesion formation, the adaptation challenge and balancing strategy of PLLA, the physicochemical modification of PLLA anti-adhesion membrane and its application in tendon anti-adhesion. In this paper, the research progress and modification strategies of PLLA membranes were systematically reviewed from the three dimensions of tissue adaptation, mechanical adaptation, and degradation adaptation. ResultsThe three-dimensional adaptation of PLLA membrane is optimized by combining materials (such as hydroxyapatite, polycaprolactone), structural design (multilayer/gradient membrane), and drug loading (anti-inflammatory drug). The balance between anti-adhesion and pro-healing is achieved, the mechanical adaptation significantly improve, and degradation is achieved (targeting the degradation cycle to 2-4 weeks to cover the tendon repair period). ConclusionIn the future, it is necessary to identify the optimal balance point of three-dimensional fitness, unify the evaluation criteria and solve the degradation side effects through the co-design of physicochemical modification and drug loading system to break through the bottleneck of clinical translation.