Self‐Activating Phosphorus‐Rich Substrate Import Enzyme Catalytic Domains for Bone Regeneration

Abstract

Enzymes play a key role in natural mineralization, but their function is disabling in bone metabolism when patients suffer severe degenerations like hypophosphatasia. To regulate bone homeostasis, a self‐activating phosphorus‐rich system is proposed on calcium glycerophosphate (CaGP) modified polyurethane (PU) fibrous substrate, wherein ample enzyme catalytic domains are imported with intestinal alkaline phosphatase (IALP) chelating and activating by calcium in situ that is testified by chemical potential evaluation. Therefore, Ca‐bonding IALP catalyzes organophosphate to phosphate locally to achieve a calcified symbiotic state, regulating mineralization and accelerating osteoinduction in vitro and in vivo. The self‐activating enzyme system promotes early osteogenic differentiation and angiogenesis, resulting in rapid healing of cranial defect with a “long‐tail” effect compared to an enzyme‐assisted system. Transcriptomic and metabolomic analyses demonstrate positive associations with neovascularization and calcium/phosphorus metabolism, specifically upregulated glycerophospholipids and calcium ions in favor of osteogenic differentiation under cytokine‐free conditions. These results provide a potential enzyme‐activating therapy in bone homeostasis and regeneration.

Enzyme-Activated Biomimetic Vesicles Confining Mineralization for Bone Maturation

“…According to this protocol, calcium ions has been introduced to the polymeric chains by CaGP fragment to stimulate ALP to promote the hydrolysis of organophosphorus in local to mimic the biomineralization, owing to alkaline phosphatase requires the presence of calcium, and magnesium ions to activate its activity . So, the enzyme activity of the ALP-loaded BVs is a pivotal factor for the premineralization process.…”

“…According to this protocol, calcium ions has been introduced to the polymeric chains by CaGP fragment to stimulate ALP to promote the hydrolysis of organophosphorus in local to mimic the biomineralization, owing to alkaline phosphatase requires the presence of calcium, and magnesium ions to activate its activity. 43 So, the enzyme activity of the ALP-loaded BVs is a pivotal factor for the premineralization process. As shown in Figure 3f, the enzyme activity of two ALP-loaded BVs was expressed by 4-nitrophenol (PNP) concentration mediated by the hydrolysis of 4-nitrophenyl phosphate disodium salt hexahydrate (PNPP).…”