The Biol Mi Logical P Cro/Nan Propert Nostruc Ties Of A Ctured T Ag-Plasm Titanium Ma Mod M Surfa Dificate Ace Ed

?Objective?The local administration of antibacterial agents on implant surfaces is frequently used to prevent implant-related bacteria contamination.Here,we aimed to immobilize silver nanoparticles?Ag NPs?onto the sandblasted and acid-etched?SLA?titanium surface by using silver plasma immersion ion implantation?Ag-PIII?.?Materials and methods?1.Ppure titanium disks of grade IV were sand blasted with large corundum grits and acid etched in a boiling mixture of HCl and H₂SO₄.Then the disks were transferred into the chamber of silver ion implantation systems.2.The surface structure and chemistry of various groups were assessed by field-emission scanning electron microscopy and X-ray photoelectron spectroscopy,respectively.The silver release after soaking the Ag-PIII groups in PBS for 30 days was assessed by inductively coupled plasma mass spectrometry.3.We evaluated the antimicrobial activities of the Ag-PIII groups against Fusobacterium nucleatum,Staphylococcus aureus and Streptococcus mutans by using Live/Dead staining assays,spread plate methods,and SEM observation.4.The in vitro compatible property of the Ag-PIII groups was investigated by using rat bone marrow mesenchymal stem cells?rBMSCs?.?Results?1.Silver is well imposed in the form of nanoparticles.As Ag-PIII duration increased,the density of particles became higher and the average size increased.2.The amounts of silver released from the Ag-PIII samples to PBS after a 30-day incubation were 3.6 ppb,4.3 ppb and 4.6 ppb,respectively.3.The reduction rates of Fusobacterium nucleatum on the three Ag-PIII groups were22%,57%and 92%,respectively.The reduction rates of Staphylococcus aureus were12%,42%and 80%,and those of Streptococcus mutans were 17%,47%and 84%.4.The antibacterial rates of the Ag-PIII groups remained almost the same after being incubated in PBS for 1 day,15 days and 30 days.Moreover,the antibacterial rates did not change even after three cycles of bacteria exposure.5.The Ag NPs immobilized using Ag-PIII technique showed almost no side effects to rBMSCs in terms of initial adhesion,cell proliferation and osteoblastic differentiation.?Conclusions?1.Ag NPs were immobilized on SLA surfaces by Ag-PIII,thus forming hierarchical titanium surfaces.The leakages of silver from Ag-PIII samples were minimal.2.The immobilized Ag NPs inhibited the proliferation of Fusobacterium nucleatum,Staphylococcus aureus and Streptococcus mutans.Gram-negative bacteria showed a higher susceptibility to Ag NPs,which might be ascribed to their less rigid cell wall structure.Moreover,the antibacterial efficacy of the immobilized Ag NPs was independent of silver release,and they were efficacious in tackling bacteria after the materials were incubated in PBS for 30 days or exposed to several cycles of bacteria.3.The immobilized Ag NPs did not exhibit apparent cytotoxicity to rBMSCs,the most well-characterized cell source involved in osseointegration.4.By using the proper Ag-PIII conditions,titanium implants with hierarchical micro/nanostructures could be endowed with excellent biological properties,which bodes well for safe and prolonged clinical applications.