The present study aims to reveal the osteogenic roles played by DNA damage response biomarkers through implementing isobaric tags for relative and absolute quantitation (iTRAQ) technique. First, sandblasted large-grit double acid-etched (SLA) titanium implant and strontium-incorporated (SLA-Sr) titanium implant were used for inserting in the tibiae of rats. iTRAQ technique was used to detect protein expression changes and identify differentially expressed proteins (DEPs). In total, 19,343 peptides and 4280 proteins were screened out. Among them, 91 and 138 DEPs were identified in the SLA-Sr group after implantation for 3 and 7 days, respectively. Ataxia-telangiectasia mutated (ATM) protein up-regulated on the 3rd day showed a trend of further up-regulation on the 7th day. Moreover, functional enrichment analyses were also conducted to explore the biological function of DEPs during the initial stage of osseointegration in vivo, which revealed that the biological functions of the DEPs on the 7th day were mainly related to “mismatch repair” and “mitotic G1 DNA damage checkpoint.” Analysis of the Reactome signaling pathway showed that ATM was associated with TP53's regulation and activation. Finally, DNA damage repair related genes were selected for validation at mRNA and protein expression levels. Real-time reverse transcription-polymerase chain reaction and immunohistochemistry validation results demonstrated that mRNA expression level of ATM was higher in SLA-Sr group. In conclusion, SLA-Sr titanium implant could initiate DNA damage repair by activating expression levels of ATM. This study was striving to reveal new faces of better osseointegration and shedding light on the biological function and underlying mechanisms of this important procedure.
Yuxuan Hou,Ruowei Yin,Junjie Li,Xiaopo Su,Chuanbao Liu,Yang Bai
Electrocaloric effect (ECE) is one of the basic features of ferroelectrics / antiferroelectrics. The positive ECE and negative ECE exhibit oppose thermal response to the variation of electric fields. This allows them to complement each other, enabling more diversified refrigeration regulation. To enhance the negative ECE and broaden its temperature range, this work investigates the impact of diffuse phase transitions in antiferroelectric Pb 1- x Sr x Zr 0.95 Ti 0.05 O 3 (PSZT) films on LaNiO 3 /Si substrates. Sr 2 + doping reduces the unit cell volume and enhances antiferroelectricity, resulting in an increment of the ECE Δ T from −2.26 K to −3.38 K. Meanwhile, it breaks the long-range antiferroelectric order to achieve a local symmetry breaking, and promotes the diffusion of the antiferroelectric-ferroelectric phase transition to significantly broaden the temperature span of the negative ECE from 33 K to over 108 K. This work demonstrates that controlling the phase transition diffusion in PSZT films effectively enhances the performance of the negative ECE and broadens its temperature span, providing a strong support for in-situ chip cooling technology.
Jin He,Haixia Ye,Yulei Li,Ju Fang,Qingsong Mei,Xiong Lu,Fuzeng Ren
The repair of large bone defects poses a grand challenge in tissue engineering. Thus, developing biocompatible scaffolds with mechanical and structural similarity to human cancellous bone is in great demand. Herein, we fabricated a three-dimensional (3D) porous iron (Fe) scaffold with interconnected pores via a template-assisted electrodeposition method. The porous Fe scaffold with a skeleton diameter of 143 μm had the porosity >90%, an average pore size of 345 μm, and a yield strength of 3.5 MPa. Such structure and mechanical strength were close to those of cancellous bone. In order to enhance the biocompatibility of the scaffold, strontium incorporated octacalcium phosphate (Sr-OCP) was coated on the skeletons of the porous Fe scaffold. The coated Sr-OCP was in the form of nanowhiskers with a mean diameter of 300 nm and length of 30 μm. Such Sr-OCP coating could effectively reduce the release rate of the Fe ions to a level which was safe for the human body. Both in vitro cytotoxicity tests by extraction method and direct contact assay confirmed that the Sr-OCP coating could promote the cell adhesion and substantially enhance the biocompatibility of the porous Fe scaffolds. Thus, the cancellous-bone-like porous structure with compatible mechanical properties and excellent biocompatibility enables the present Sr-OCP coated porous Fe scaffold to be a promising candidate for bone repair and regeneration.
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