Long-term chronic inflammation after Achilles tendon injury is critical for tendinopathy. Platelet-rich plasma (PRP) injection, which is a common method for treating tendinopathy, has positive effects on tendon repair. In addition, tendon-derived stem cells (TDSCs), which are stem cells located in tendons, play a major role in maintaining tissue homeostasis and postinjury repair. In this study, injectable gelatine methacryloyl (GelMA) microparticles containing PRP laden with TDSCs (PRP–TDSC–GM) were prepared by a projection-based 3D bioprinting technique. Our results showed that PRP–TDSC–GM could promote tendon differentiation in TDSCs and reduce the inflammatory response by downregulating the PI3K–AKT pathway, thus promoting the structural and functional repair of tendons in vivo. Graphical Abstract

Muscular atrophy after limb fracture is a frequently occurring complication with multiple causes. Different treatments and targeted rehabilitation procedures should be carried out based on the causes. However, bedside evaluation methods are invasive in clinical practice nowadays, lacking reliable non-invasive methods. In this study, we propose a non-invasive flexible surface electromyography system with machine learning algorithms to distinguish nerve-injury and limb immobilization-related atrophy. First, a flexible surface electromyography sensor was designed and verified by in vitro tests for its robustness and flexibility. Then, in vivo tests on rats proved the reliability compared with the traditional invasive diagnosis method. Finally, this system was applied for the diagnosis of muscular atrophy in 10 patients. The flexible surface electromyography sensor can achieve a max strain of 12.0%, which ensures close contact with the skin. The in vivo tests on rats show great comparability with the traditional invasive diagnosis method. It can achieve a high specificity of 95.28% and sensitivity of 98.98%. Application on patients reaches a relatively high specificity of 89.44% and sensitivity of 91.94%. The proposed painless surface electromyography system can be an easy and accurate supplementary for bedside muscular atrophy causes evaluation, holding excellent contact with the body.

Senescent cells (SnCs) are increasingly recognized as key contributors to osteoarthritis, with conventional strategies centered on their elimination. However, senolytic approaches face mounting limitations, driving the need for refined interventions. Here, we exploit SnCs’ lipid metabolic signature to develop a senotherapeutic strategy. Given the universal lipid accumulation in SnCs and the dual role of lipids as both metabolic liabilities and essential lubricants, we engineer an injectable nanoliposuction hydrogel platform designed for “waste recycling”. This system removes excess lipids to mitigate senescence-associated secretory phenotype (SASP) propagation and incorporates the harvested lipids as a pivotal component of the biomimetic lubricating system, thereby alleviating mechanical allodynia and cartilage wear. This strategy circumvents potential side effects associated with direct SnCs clearance and repurposes these traditionally harmful cells as functional resources. Our findings establish a shift in the philosophy of senescence therapy, transitioning the focus from destructive ablation to spatially adaptive reallocation of metabolites.