Increasing interest in aerogels among industrial sectors and the scientific community has sparked a sustained effort to develop methodologies for rational organization of aerogels for broader applications. Here we demonstrate that anisotropically compression-resilient cellulose/silica aerogels with tailorable macropores can be realized through guided self-assembly and controlled mineralization of bacterial cellulose. The cellulose/silica aerogels replicate the mesostructural features of modified bacterial cellulose with the macropores tailored during the biosynthesis using polystyrene spheres. Silica deposition surrounding bacterial cellulose nanofibers is controlled by moderating the hydrolysis and polycondensation of tetrapropoxysilane in the presence of cetyltrimethylammonium bromide. Cellulose/silica withstands 100 cycles with almost 100% height recovery along the growth direction and 1 cycle with 86.2% height recovery perpendicular to the growth direction at 60% compression strain. The anisotropic compression resilience is attributed to a multiscale deformation involving silica nanoparticles size, bead-on-string nanostructure, and oriented mesostructure of wavy fibers with cellular pores. The potential of the cellulose/silica aerogels for oily water cleansing is illustrated. Our work opens up new possibilities for bacterial cellulose-based advanced materials through in vivo mesostructure engineering and controlled mineralization.
Xi Cui,Lingling Xu,Yizhu Shan,Jiaxuan Li,Jianying Ji,Engui Wang,Baokun Zhang,Xiaozhou Wen,Yuan Bai,Dan Luo,Chunying Chen,Zhou Li
Orderly hierarchical structure with balanced mechanical, chemical, and electrical properties is the basis of the natural bone microenvironment. Inspired by nature, we developed a piezocatalytically-induced controlled mineralization strategy using piezoelectric polymer poly-L-lactic acid (PLLA) fibers with ordered micro-nano structures to prepare biomimetic tissue engineering scaffolds with a bone-like microenvironment (pcm-PLLA), in which PLLA-mediated piezoelectric catalysis promoted the in-situ polymerization of dopamine and subsequently regulated the controllable growth of hydroxyapatite crystals on the fiber surface. PLLA fibers, as analogs of mineralized collagen fibers, were arranged in an oriented manner, and ultimately formed a bone-like interconnected pore structure; in addition, they also provided bone-like piezoelectric properties. The uniformly sized HA nanocrystals formed by controlled mineralization provided a bone-like mechanical strength and chemical environment. The pcm-PLLA scaffold could rapidly recruit endogenous stem cells, and promote their osteogenic differentiation by activating cell membrane calcium channels and PI3K signaling pathways through ultrasound-responsive piezoelectric signals. In addition, the scaffold also provided a suitable microenvironment to promote macrophage M2 polarization and angiogenesis, thereby enhancing bone regeneration in skull defects of rats. The proposed piezocatalytically-induced controllable mineralization strategy provides a new idea for the development of tissue engineering scaffolds that can be implemented for multimodal physical stimulation therapy.
危险品化学品经营许可证（带存储）