Effects of Argon Gas Plasma Treatment on Biocompatibility of Nanostructured Titanium

In this study, we applied argon plasma treatment to titanium surfaces with nanostructures deposited by concentrated alkali treatment and investigated the effects on the surface of the material and the tissue surrounding an implant site. The results showed that the treatment with argon plasma removed carbon contaminants and increased the surface energy of the material while the nanoscale network structure deposited on the titanium surface remained in place. Reactive oxygen species reduced the oxidative stress of bone marrow cells on the treated titanium surface, creating a favorable environment for cell proliferation. Good results were observed in vitro evaluations using rat bone marrow cells. The group treated with argon plasma exhibited the highest apatite formation in experiments using simulated body fluids. The results of in vivo evaluation using rat femurs revealed that the treatment improved the amount of new bone formation around an implant. Thus, the results demonstrate that argon plasma treatment enhances the ability of nanostructured titanium surfaces to induce hard tissue differentiation and supports new bone formation around an implant site.

Scalable Assembly of High-Quality Graphene Films via Electrostatic-Repulsion Aligning

Assembling pristine graphene into freestanding films featuring high electrical conductivity, superior flexibility, and robust mechanical strength aims at meeting the all-around high criteria of new-generation electronics. However, voids and defects produced in the macroscopic assembly process of graphene nanosheets severely degrade the performance of graphene films, and mechanical brittleness often limits their applications in wide scenarios. To address such challenges, an electrostatic-repulsion aligning strategy is demonstrated to produce highly conductive, ultraflexible, and multifunctional graphene films. Typically, the high electronegativity of titania nanosheets (TiNS) induces the aligning of negatively charged graphene nanosheets via electrostatic repulsion in the film assembly. The resultant graphene films show fine microstructure, enhanced mechanical properties, and improved electrical conductivity up to 1.285 × 10⁵ S m^-1 . Moreover, the graphene films can withstand 5000 repeated folding without structural damage and electrical resistance fluctuation. These comprehensive improved properties, combined with the facile synthesis method and scalable production, make these graphene films a promising platform for electromagnetic interference (EMI) shielding and thermal-management applications in smart and wearable electronics.