Jingqi Ma,Lili Lin,Yi Zuo,Qin Zou,Xin Ren,Jidong Li,Yubao Li
In the study, a specific material system that contains poly-(ε-caprolactone) (PCL), polyvinyl acetate (PVAc) and hydroxyapatite (HA) was used to fabricate porous scaffolds employing a 3D printing technique for bone regeneration. Four groups of 3D printing scaffolds were fabricated: PCL, PCL/PVAc, PCL/HA and PCL/PVAc/HA for comparision. The morphologies, mechanical properties and biological characteristics of these scaffolds were analyzed using SEM, a material testing machine, in vitro cell culture and in vivo animal experiments. The results showed that these 3D printed scaffolds possessed porous channel structures with a hole size of 375–475 μm and porosity of 74.1–76.1%. The compressive moduli of the scaffolds increased with the addition of HA and decreased with the addition of PVAc. The PCL/PVAc/HA scaffold exhibited higher cell proliferation and bone formation rates than other groups (p < 0.001), which could be attributed to the synergistic effect of PAVc and HA components. Two types of new bone formation patterns in the scaffold were found in this study: one is the new bone formed directly on the grid matrix, and the other is the new bone initially formed in the center of the scaffold channel and then remolded to concentric circles. The osteogenesis pattern of the latter is analogous to the osteon structure of a cortical bone. The 3D printed scaffold based on PCL/PVAc/HA tri-component system is a promising prospect for future individualized bone repair applications.
Tailoring the surface properties of poly(dimethylsiloxane) (PDMS) is essential for the advancement of its applications. However, the modification process is usually complicated and limited due to the chemical inertness of the surfaces of PDMS. Here, we report for the first time, a facile and versatile method for the functional surface modification of PDMS via visible light-induced grafting polymerization at room temperature. This modification is readily achieved in two steps: (1) covalently integrating alkyl bromine into the PDMS networks using a simple mixing procedure and (2) visible light-induced surface grafting polymerization using Mn2(CO)10. We have demonstrated that the PDMS surface can be functionalized with a wide variety of polymers via covalent grafting, such as poly(trifluoroethyl methacrylate) (PTFEMA), poly(N-isopropylacrylamide) (PNIPAAm), poly(acrylic acid) (PAA) and poly(vinyl acetate) (PVAc). As an example, after the grafted PVAc was transformed into its hydrophilic analogue poly(vinyl alcohol) (PVA), anti-biofouling functionalization of PDMS was obtained. The anti-biofouling properties of the functionalized PDMS were demonstrated using cell adhesion and bacterial adhesion tests. Moreover, the grafting kinetics of PVAc showed that this process was fast and efficient.
Xinrun Yu,Longlong Wang,Jun Ma,Xingwei Sun,Xinhong Zhou,Guanglei Cui
Solid polymer electrolytes (SPEs) are considered to be the key to solve the safety hazards and cycling performance of liquid high-voltage lithium metal batteries (HVLMBs), but still suffer from low conductivity and poor interfacial compatibility. Here, polyvinylidene fluoride–polyvinyl acetate-based (PVDF–PVAC) rigid–flexible coupling SPE selectively wetted by a tetramethylene sulfone (TMS) is prepared for high-performance and superior-safety HVLMBs. The intermolecular interactions in such SPE significantly facilitate lithium-ion conductivity and electrolyte/electrode interface wettability. Moreover, PVAC selectively wetted with the TMS enhances interface compatibility with Li anodes and high-voltage LiCoO 2 cathodes. As a result, the as-assembled LiCoO 2 /lithium-metal solid-state batteries present excellent cyclability with 85% capacity retention after 200 cycles between 3.0 and 4.5 V at room temperature. Furthermore, pouch cells with the as-prepared SPE exhibit brilliant safety and superior interfacial compatibility. This study offers a promising and general selectively wetted design strategy to handle the compatibility and safety issues in HVLMBs.
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