Large-Scale Nanofiber Manufacturing| A Coordinated cascade Therapy-Based janus FibrousMembrane Drives Bone Regeneration throughMediating the Transformation of Energy MetabolismPathway

Professor Bai Yan from Chongqing Medical University & Associate Researcher Li Jiangfeng from Southwest Hospital in AFM: Janus Fibrous Membrane Based on Coordinated Cascade Therapy for Bone Regeneration

Bone defect regeneration is a dynamic and complex process involving spatiotemporal coordination of multiple cell populations, precise regulation of bioactive molecules, and cascade responses of signaling pathways. Achieving precise regulation of different growth factors at various bone regeneration stages for synergistic cascade therapy is crucial. Although current research has made significant progress in growth factor-induced bone regeneration mechanisms, the deeper mechanisms through which they influence bone regeneration by regulating cellular energy metabolism reprogramming remain to be elucidated.

Recently, Professor Bai Yan's team from Chongqing Medical University and Associate Researcher Li Jiangfeng's team from Southwest Hospital collaborated to design a novel metabolically activated Janus fibrous membrane. The inner fiber layer achieves controlled growth factor release to coordinately regulate BMSC energy metabolism, while the outer fiber layer provides sustainable antibacterial activity and barrier function to drive osteogenic differentiation and bone regeneration, offering a new therapeutic strategy. This work was published in Advanced Functional Materials as "A Coordinated Cascade Therapy-Based Janus Fibrous Membrane Drives Bone Regeneration through Mediating the Transformation of Energy Metabolism Pathway". Cheng Xiting (2024 master's graduate), Xu Na and Wu Hao are co-first authors, with Professor Bai Yan and Associate Researcher Li Jiangfeng as corresponding authors.

Preparation and Characterization of Janus Fibrous Membrane:
This study aimed to construct a multifunctional nanofibrous membrane that could effectively regulate BMSC energy metabolism through controlled growth factor release for efficient bone regeneration (Figure 1). Researchers used electrospinning to prepare aligned PCL/PLGA@ZnO fibers combined with coaxial electrospinning and LBL technology to fabricate core-shell Gelatin/PLLA nanofibers loaded with BMP-2 (core) and aFGF (shell). The inner Gelatin@BMP-2/PLLA@aFGF nanofibers sequentially released different growth factors according to bone regeneration cascade logic, achieving sustained BMP-2 release throughout bone repair while rapidly releasing aFGF in early stages (Figure 2).

Figure 1: Preparation, application, bioactivity and mechanisms of multifunctional Janus membrane

Figure 2: Preparation and characterization of Janus membrane

In Vitro Osteogenic Effects and Energy Metabolism Mechanisms:
The study further verified that dual growth factor release from Janus membrane's inner layer synergistically promoted BMSC osteogenic differentiation (Figure 3). Genomic screening revealed that growth factor-loaded Janus membrane's osteoinductive capacity was closely related to oxidative phosphorylation, glutathione metabolism, and PI3K-AKT signaling pathways (Figure 4). The membrane activated BMSC PI3K-AKT pathway, significantly improving glucose-derived OXPHOS by enhancing GLUT4 and metabolic enzyme (PFKM, IDH2) expression while maintaining low-ROS microenvironment required for osteogenesis, ultimately increasing osteogenic gene transcription (Figure 5).

Figure 3: In vitro osteogenic function of Janus membrane

Figure 4: RNA-seq reveals potential mechanisms of Janus membrane-induced BMSC osteogenesis

Figure 5: Osteogenic mechanism of Janus membrane

In Vivo Bone Repair Evaluation:
A rat critical-size calvarial defect model demonstrated Janus membrane's osteoinductive capacity, confirming that time-controlled dual release of aFGF and BMP-2 produced better and faster vascular/osseous regeneration (Figure 6).

Figure 6: In vivo guided bone regeneration and angiogenesis by Janus membrane

Conclusion:
Using coaxial electrospinning and LBL self-assembly, researchers successfully prepared a coordinated cascade therapy-based Janus membrane. Results showed significantly enhanced OXPHOS as the primary energy supply pathway was key to driving BMSC osteogenic differentiation. The outer structure effectively prevented epithelial invasion and bacterial infection, while the core-shell inner layer enabled sequential aFGF/BMP-2 release, significantly promoting angiogenesis and osteogenesis both in vitro and in vivo. This study not only reveals growth factors' synergistic mechanisms in bone regeneration through energy metabolism regulation but also provides important theoretical foundations and potential applications for tissue engineering.