Rivet-Inspired Modification of Carbon Nanotubes by In Situ-Reduced Ag Nanoparticles To Enhance the Strength and Ductility of Zn Implants

Abstract

Zinc shows promise for bone repair applications, while its strength and ductility require to be improved. Carbon nanotubes (CNTs) are exceptional reinforcements due to their superior strength, ultrahigh Young’s modulus, and large aspect ratio. However, their strong agglomeration and weak interfacial bonding with the matrix are key bottleneck problems restricting the reinforcing effect. In this study, Ag nanoparticles were in situ reduced on CNTs and then the CNT@Ag powders were used to prepare Zn-CNT@Ag implants by laser powder bed fusion. Results showed that Ag reacted with Zn to form a “knot”-like AgZn3 phase. It had the same lattice structure (HCP) with Zn, which indicated a good lattice matching with the matrix, thus improving the dispersion of CNTs. More significantly, the knot played a “rivet” role and enhanced the load transfer capacity, which advantaged the CNT strengthening effects by assisting in transferring the load. Moreover, it enhanced the heterogeneous nucleation effects during solidification, which weakened the texture strength of the matrix and thus increased the ductility by improving the sliding capacity. The compressive yield strength, ultimate tensile strength, and elongation of the Zn-CNT@Ag implant were increased by 22, 26, and 17% in comparison to Zn-CNTs. Moreover, the Zn-CNT@Ag implant exhibited favorable antibacterial activity with a bacterial inhibition rate of 87.79%. Additionally, it also exhibited a suitable degradation rate and acceptable biocompatibility.

Synergetic Effects of Nanoscale ALD–HfO2 Coatings and Bionic Microstructures for Antiadhesive Surgical Electrodes: Improved Cutting Performance, Antibacterial Property, and Biocompatibility

“…coli and Gram-positive S. aureus. , Figure a shows that E. coli colonies separated from the initial (as a control) and BM electrodes were densely and uniformly distributed on the plate, suggesting poor antibacterial properties.…”

“…41,42 To evaluate bacterial adhesion to different electrodes, in vitro antibacterial tests were conducted with two kinds of bacterial species, i.e., Gram-negative E. coli and Gram-positive S. aureus. 43,44 Figure 7a shows that E. coli colonies separated from the initial (as a control) and BM electrodes were densely and uniformly distributed on the plate, suggesting poor antibacterial properties. In contrast, E. coli colonies separated from the coated electrode were relatively reduced due to the antibacterial performance of nanoscale HfO 2 coatings that were probably induced by specific surface chemistry.…”

Role of heterogenous microstructure and deformation behavior in achieving superior strength-ductility synergy in zinc fabricated via laser powder bed fusion

“…In this study, the LPBF-printed Zn achieves superior ductility and high tensile strength compared with the counterparts prepared by conventional processes such as casting [41,[57][58][59][60][61], hot extrusion [42,[62][63][64][65][66][67], and hot rolling [43,62] (figure 14(a)). Among all reported LPBF-printed Zn samples to date [21,23,27,29,[68][69][70][71][72][73][74][75][76][77][78], the printed Zn at the horizontal plane demonstrates the highest mechanical properties with a UTS of 128.7 MPa and a ductility of 12.1%, enabling it as a promising candidate for designing Zn-based implant in biomedical applications. It is worth noting that LPBFprinted Zn generally displays significant mechanical anisotropy.…”

Surface modifications of biomaterials in different applied fields

“…Shuai et al reduced silver nanoparticles on carbon nanotubes (CNTs) in situ . 114 The CNT@Ag powder was then prepared by laser powder bed fusion (LPBF) to prepare the Zn-CNTs@Ag scaffold implant, which had an orthogonal porous structure that facilitates cell migration, tissue formation, and nutrient transportation. The scaffold exhibited favourable antibacterial activity and biocompatibility.…”