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Abstract Background and aims Osteoarthritis (OA) is a prevalent degenerative joint disorder, marked by the progressive degeneration of joint cartilage, synovial inflammation, and subchondral bone hyperplasia. The synovial tissue plays a pivotal role in cartilage regulation. Exosomes (EXOs), small membrane-bound vesicles released by cells into the extracellular space, are crucial in mediating intercellular communication and facilitating the exchange of information between tissues. Our study aimed to devise a hydrogel microsphere infused with SOD3-enriched exosomes (S-EXOs) to protect cartilage and introduce a novel, effective approach for OA treatment. Materials and methods We analyzed single-cell sequencing data from 4247 cells obtained from the GEO database. Techniques such as PCR, Western Blot, immunofluorescence (IF), and assays to measure oxidative stress levels were employed to validate the cartilage-protective properties of the identified key protein, SOD3. In vivo, OA mice received intra-articular injections of S-EXOs bearing hydrogel microspheres, and the effectiveness was assessed using safranine O (S.O) staining and IF. Results Single-cell sequencing data analysis suggested that the synovium influences cartilage via the exocrine release of SOD3. Our findings revealed that purified S-EXOs enhanced antioxidant capacity of chondrocytes, and maintained extracellular matrix metabolism stability. The S-EXO group showed a significant reduction in mitoROS and ROS levels by 164.2% (P

Infectious bone defects are one of the thorny problems faced by orthopedists. Developing prosthetic materials with antimicrobial osteogenic features is a key solution. Biodegradable Polyacrylic acid (PAA)-based hydrogels have gained attention for their exceptional qualities. However, the influence of zinc ions on PAA-based mineralized hydrogels remains understudied. In this paper, Poly (acrylic acid)-calcium-zinc (PA-CZ) biomineralized hydrogel was prepared through ionic cross-linking and biomineralization. In vitro bacterial and cell tests demonstrated the hydrogel’s exceptional biocompatibility, antibacterial, and osteogenic traits, along with good mechanical strength. The PA-CZ mineralized hydrogel lays the foundation for developing orthopedic implants with antimicrobial osteogenic features and offers a promising approach for treating infected bone defects.

Insufficient initial vascularization plays a pivotal role in the ineffectiveness of bone biomaterials for treating bone defects. Consequently, enhancing the angiogenic properties of bone repair biomaterials holds immense importance in augmenting the efficacy of bone regeneration. In this context, we have successfully engineered a composite hydrogel capable of promoting vascularization in the process of bone regeneration. To achieve this, the researchers first prepared an aminated bioactive glass containing zinc ions (AZnBg), and hyaluronic acid contains aldehyde groups (HA-CHO). The composite hydrogel was formed by combining AZnBg with gelatin methacryloyl (GelMA) and HA-CHO through Schiff base bonding. This composite hydrogel has good biocompatibility. In addition, the composite hydrogel exhibited significant osteoinductive activity, promoting the activity of ALP, the formation of calcium nodules, and the expression of osteogenic genes. Notably, the hydrogel also promoted umbilical vein endothelial cell migration as well as tube formation by releasing zinc ions. The results of in vivo study demonstrated that implantation of the composite hydrogel in the bone defect of the distal femur of rats could effectively stimulate bone generation and the development of new blood vessels, thus accelerating the bone healing process. In conclusion, the combining zinc-containing bioactive glass with hydrogels can effectively promote bone growth and angiogenesis, making it a viable option for the repair of critical-sized bone defects.

The process of bone regeneration is intricately regulated by various cytokines at distinct stages. The establishment of early and efficient vascularization, along with the maintenance of a sustained osteoinductive microenvironment, plays a crucial role in the successful utilization of bone repair materials. This study aimed to develop a composite hydrogel that would facilitate the creation of an osteogenic microenvironment for bone repair. This was achieved by incorporating an early rapid release of VEGF and a sustained slow release of BMP-2. Herein, the Schiff base was formed between VEGF and the composite hydrogel, and VEGF could be rapidly released to promote vascularization in response to the early acidic bone injury microenvironment. Furthermore, the encapsulation of BMP-2 within mesoporous silica nanoparticles enabled a controlled and sustained release, thereby facilitating the process of bone repair. Our developed composite hydrogel released more than 80% of VEGF and BMP-2 in the acidic medium, which was significantly higher than that in the neutral medium (about 60%). Moreover, the composite hydrogel demonstrated a significant improvement in the migratory capacity and tube formation ability of human umbilical vein endothelial cells (HUVECs). Furthermore, the composite hydrogel exhibited an augmented ability for osteogenesis, as confirmed by the utilization of ALP staining, alizarin red staining, and the upregulation of osteogenesis-related genes. Notably, the composite hydrogel displayed substantial osteoinductive properties, compared with other groups, the skull defect in the composite hydrogels combined with BMP-2 and VEGF was full of new bone, basically completely repaired, and the BV/TV value was greater than 80%. The outcomes of animal experiments demonstrated that the composite hydrogel effectively promoted bone regeneration in cranial defects of rats by leveraging the synergistic effect of an early rapid release of VEGF and a sustained slow release of BMP-2, thereby facilitating vascularized bone regeneration. In conclusion, our composite hydrogel has demonstrated promising potential for vascularized bone repair through the enhancement of angiogenesis and osteogenic microenvironment.

The detection of pathogens in medical wastewater is crucial due to the high content of pathogenic microorganisms that pose significant risks to public health and the environment. Medical wastewater, which includes waste from infectious disease and tuberculosis facilities, as well as comprehensive medical institutions, contains a variety of pathogens such as bacteria, viruses, fungi, and parasites. Traditional detection methods like nucleic acid detection and immunological assays, while effective, are often time-consuming, expensive, and not suitable for rapid detection in underdeveloped areas. Electrochemical biosensors offer a promising alternative with advantages including simplicity, rapid response, portability, and low cost. This paper reviews the sources of pathogens in medical wastewater, highlighting specific bacteria (e.g., E. coli, Salmonella, Staphylococcus aureus), viruses (e.g., enterovirus, respiratory viruses, hepatitis virus), parasites, and fungi. It also discusses various electrochemical biosensing techniques such as voltammetry, conductometry, impedance, photoelectrochemical, and electrochemiluminescent biosensors. These technologies facilitate the rapid, sensitive, and specific detection of pathogens, thereby supporting public health and environmental safety. Future research may should pay more attention on enhancing sensor sensitivity and specificity, developing portable and cost-effective devices, and innovating detection methods for diverse pathogens to improve public health protection and environmental monitoring.

The bone defect caused by fracture, bone tumor, infection, and other causes is not only a problematic point in clinical treatment but also one of the hot issues in current research. The development of bone tissue engineering provides a new way to repair bone defects. Many animal experimental and rising clinical application studies have shown their excellent application prospects. The construction of rapid vascularization of tissue-engineered bone is the main bottleneck and critical factor in repairing bone defects. The rapid establishment of vascular networks early after biomaterial implantation can provide sufficient nutrients and transport metabolites. If the slow formation of the local vascular network results in a lack of blood supply, the osteogenesis process will be delayed or even unable to form new bone. The researchers modified the scaffold material by changing the physical and chemical properties of the scaffold material, loading the growth factor sustained release system, and combining it with trace elements so that it can promote early angiogenesis in the process of induced bone regeneration, which is beneficial to the whole process of bone regeneration. This article reviews the local vascular microenvironment in the process of bone defect repair and the current methods of improving scaffold materials and promoting vascularization.