Microalgae-Based Tunable Hierarchical Microparticles for Multifunctional Wound Therapy

Microalgae-derived microparticles have garnered significant interest for biomedical applications, yet their potential remains constrained by limited control over hierarchical micro-/nanostructure fabrication. Here, we engineer biohybrid microparticles featuring tunable 3D architectures through a controllable strategy, wherein vertically aligned ZnO nanotubes (NTs) are epitaxially grown on biochar microspheres derived from Chlorella cells. Density functional theory calculations confirm a 2-fold enhancement in Zn²⁺ release kinetics from ZnO NTs compared to conventional nanorods, attributed to increased surface area and reduced ionic diffusion pathways. The hierarchically structured microparticles are incorporated into a bioinspired Janus wound dressing with asymmetric wettability gradients, enabling synergistic unidirectional biofluid drainage, photothermal evaporation, and NIR/Zn²⁺-enhanced sterilization. In vivo wound tests verify treatment efficacy with impressive antibacterial performance and accelerated wound closure. Furthermore, effective alleviate inflammation is also achieved with significant enhancement in granulation tissue thickness and collagen deposition. This work establishes a scalable biotemplating platform for constructing multifunctional materials with hierarchical architectures, offering significant potential in precision wound treatment and regenerative engineering.