EDITORIAL
2025, 6(1): 1–3. doi:https://doi.org/10.12336/biomatertransl.2025.01.001
REVIEW
2025, 6(1): 4–23. doi:https://doi.org/10.12336/biomatertransl.2025.01.002
Mitochondrial transplantation (MT), an innovative regenerative technique widely used to treat diseases caused by mitochondrial dysfunction, shows great promise for clinical application. This procedure can increase the number of mitochondria and improve the function of damaged mitochondria, resulting in increased adenosine triphosphate levels, decreased reactive oxygen species production, improved Ca2+ buffering capacity, modulated inflammatory response, and reduced apoptosis to protect cells, thus promoting tissue repair. In this review, we describe research advances in MT over the last five years, focusing on its application in treating various diseases, including ischaemic injuries (of the kidney, heart, lung, and liver), neurodegenerative disorders, spinal cord injury, sepsis, diabetes mellitus, stroke, and ultraviolet radiation injuries, as well as in procedures such as organ transplantation, focusing on instances where MT demonstrated good efficacy. We also cover the application of engineered mitochondria and mitochondrial combination therapies and present the latest advances in improving MT efficiency, as well as the current clinical applications and shortcomings of MT, aiming to provide a theoretical foundation for enhanced MT utilisation in the future.

REVIEW
2025, 6(1): 24–39. doi:https://doi.org/10.12336/biomatertransl.2025.01.003
Sonodynamic therapy (SDT) has emerged as a cutting-edge strategy for combating multidrug-resistant bacterial infections. Unlike conventional antibiotics, SDT leverages the generation of reactive oxygen species during the treatment process to inflict multifaceted damage on bacterial cells, thereby significantly reducing the likelihood of developing drug resistance. Compared to other physical sterilisation methods, such as ultraviolet irradiation, SDT offers enhanced tissue penetration, making it particularly suitable for addressing deep-seated infections, including osteomyelitis. Despite its significant advantages, the clinical translation of SDT for antibacterial applications faces several challenges. This review discusses the fundamental mechanisms of SDT, with a focus on phenomena such as cavitation-induced reactions and piezocatalytic generation of reactive oxygen species. Furthermore, it provides a comprehensive analysis of various sonosensitisers used in SDT, emphasising their potential to enhance therapeutic outcomes in areas such as infected wound healing, bone regeneration, and the mitigation of deep tissue inflammation. While SDT shows great promise in addressing multidrug-resistant bacterial infections, further research and development are essential to overcome existing limitations and unlock its full clinical potential.

REVIEW
2025, 6(1): 40–54. doi:https://doi.org/10.12336/biomatertransl.2025.01.004
Rheumatoid arthritis is a chronic autoimmune disease characterised by inflammation and progressive joint damage, necessitating innovative therapeutic strategies. Conventional rheumatoid arthritis treatments, including disease-modifying antirheumatic drugs, nonsteroidal anti-inflammatory drugs, glucocorticoids, and biologics, often administered through systemic or intra-articular ways. These drugs often have low accumulation and/or retention in articular cartilage, causing dose-limiting toxicities and reduced efficacy. This review summarises recent advances in injectable drug delivery systems, specifically hydrogels, microspheres, and nanoparticles, highlighting their potential to enhance rheumatoid arthritis therapy. The outstanding potential of these systems was demonstrated; however, substantial research remains to be conducted to optimise their performance and safety.

REVIEW
2025, 6(1): 55–72. doi:https://doi.org/10.12336/biomatertransl.2025.01.005
The key role and impact of nanotechnology in vaccine development became particularly prominent following the outbreak of the coronavirus disease 2019 (COVID-19) pandemic in 2019. Especially in the process of designing and optimising COVID-19 vaccines, the application of nanomaterials significantly accelerated vaccine development and efficient delivery. In this review, we categorised and evaluated conventional vaccines, including attenuated live vaccines, inactivated vaccines, and subunit vaccines, highlighting their advantages and limitations. We summarised the development history, mechanisms, and latest technologies of vaccine adjuvants, emphasising their critical role in immune responses. Furthermore, we focused on the application of nanotechnology in the vaccine field, detailing the characteristics of nanoparticle vaccines, including virus-like particles, lipid-based carriers, inorganic nanoparticles, and polymer-based carriers. We emphasised their potential advantages in enhancing vaccine stability and immunogenicity, as well as their ability to deliver vaccines and present antigens through various routes. Despite facing challenges such as low drug loading efficiency, issues with long-term storage, high costs, and difficulties in large-scale production, nano-vaccines hold promise for the future. This review underscores the pivotal role and prospects of nanotechnology in vaccine development, offering new pathways and strategies to address current and future disease challenges.

RESEARCH ARTICLE
2025, 6(1): 73–84. doi:https://doi.org/10.12336/biomatertransl.2025.01.006
Photothermal therapy is a safe and effective tumour treatment strategy due to its excellent spatiotemporal controllability. However, interferon gamma in the tumour microenvironment is upregulated after photothermal therapy, which enhances the expression of programmed cell death ligand 1 (PD-L1) in tumour cells. This further promotes immunosuppression and tumour metastasis, resulting in a poor prognosis in cancer therapy. Traditional nanodrugs often face challenges in penetrating the dense extracellular matrix of solid tumours, whereas certain probiotics possess the ability to specifically colonise the core regions of tumours. In this research, we used Escherichia coli Nissle 1917 (ECN) as a chassis cell and self-assembly polydopamine (PDA) on the ECN surface. The black PDA@ECN (notes as PE) actively colonises at the tumour site and produces a photothermal effect under 808 nm laser irradiation to kill tumour cells. To overcome the high expression of PD-L1 induced after photothermal therapy, metformin (MET) was also encapsulated in PE to form PDA@MET@ECN (notes as PME). In vivo experiments demonstrated that PME effectively inhibited the PD-L1 expression and growth of CT26 tumour cells. Overall, PME reverses the immunosuppressive tumour microenvironment and enhances the effect of photothermal/immune therapy in tumour treatment.

RESEARCH ARTICLE
2025, 6(1): 85–102. doi:https://doi.org/10.12336/biomatertransl.2025.01.007
Orthopedic implant-associated infections pose a significant clinical challenge, often requiring surgical intervention along with systemic antibiotic treatments. To address this issue, we developed a novel approach using Ångstrom-scale silver particles (AgÅPs) with broad-spectrum antibacterial properties. Specifically, we formulated a polyethylene glycol hydrogel infused with AgÅPs (Gel-AgÅPs) designed for treating fracture fixation infections. This novel hydrogel formulation is injectable, ensuring precise adherence to both the exposed tissue and fracture surfaces, thereby allowing the direct targeted action of AgÅPs at the infection site. The Gel-AgÅPs significantly reduced the infection caused by Escherichia coli (a model pathogen of orthopedic implant infection) in a murine femoral fracture model. Moreover, the Gel-AgÅPs-treated infected fractures healed completely within 6 weeks, exhibiting bone formation and mechanical strength comparable to those of uninfected fractures. Further analysis revealed a significant downregulation of local inflammatory response as evidenced by a lower expression of inflammatory markers in Gel-AgÅPs-treated fractures compared to untreated infected controls. Furthermore, Gel-AgÅPs exhibited a unique ability to inhibit osteoclast differentiation, a critical factor in infection-induced bone degradation, without impacting osteoblast activity. In conclusion, Gel-AgÅPs exerted a dual therapeutic effect by eradicating bacterial infection and mitigating inflammation-induced osteoclast activity, thereby expediting infected fracture healing. This innovative approach is a promising therapeutic alternative to conventional antibiotic treatments, potentially transforming the treatment landscape for orthopedic implant-associated infections.

COMMENTARY
2025, 6(1): 103–105. doi:https://doi.org/10.12336/biomatertransl.2025.01.008
COMMENTARY
2025, 6(1): 106–109. doi:https://doi.org/10.12336/biomatertransl.2025.01.009
COMMENTARY
2025, 6(1): 110–111. doi:https://doi.org/10.12336/biomatertransl.2025.01.010