Scanning-electron-microscopy observations and mechanical characteristics of ion-beam-sputtered surgical implant alloys

An electron bombardment ion thruster was used as an ion source to sputter the surfaces of orthopedic prosthetic metals. Scanning electron microscopy photomicrographs were made of each ion beam textured surface. The effect of ion texturing an implant surface on its bond to bone cement was investigated. A Co-Cr-W alloy and surgical stainless steel were used as representative hard tissue implant materials to determine effects of ion texturing on bulk mechanical properties. Work was done to determine the effect of substrate temperature on the development of an ion textured surface microstructure. Results indicate that the ultimate strength of the bulk materials is unchanged by ion texturing and that the microstructure will develop more rapidly if the substrate is heated prior to ion texturing

Ion beam sputter etching of orthopedic implanted alloy MP35N and resulting effects on fatigue

The effects of two types of argon ion sputter etched surface structures on the tensile stress fatigue properties of orthopedic implant alloy MP35N were investigated. One surface structure was a natural texture resulting from direct bombardment by 1 keV argon ions. The other structure was a pattern of square holes milled into the surface by a 1 keV argon ion beam through a Ni screen mask. The etched surfaces were subjected to tensile stress only in fatigue tests designed to simulate the cyclic load conditions experienced by the stems of artificial hip joint implants. Both types of sputter etched surface structures were found to reduce the fatigue strength below that of smooth surface MP35N

Mechanical properties of ion-beam-textured surgical implant alloys

An electron-bombardment Hg ion thruster was used as an ion source to texture surfaces of materials used to make orthopedic and/or dental prostheses or implants. The materials textured include 316 stainless steel, titanium-6% aluminum, 4% vanadium, and cobalt-20% chromium, 15% tungsten. To determine the effect of ion texturing on the ultimate strength and yield strength, stainless steel and Co-Cr-W alloy samples were tensile tested to failure. Three types of samples of both materials were tested. One type was ion-textured (the process also heats each sample to 300 C), another type was simply heated to 300 C in an oven, and the third type was untreated. Stress-strain diagrams, 0.2% offset yield strength data, total elongation data, and area reduction data are presented. Fatigue specimens of ion textured and untextured 316 stainless steel and Ti-6% Al-4% V were tested. Included as an ion textured sample is a Ti-6% Al-4% V sample which was ion machined by means of Ni screen mask so as to produce an array of 140 mu m x 140 mu m x 60 mu m deep pits. Scanning electron microscopy was used to characterize the ion textured surfaces

The use of an ion-beam source to alter the surface morphology of biological implant materials

An electron bombardment, ion thruster was used as a neutralized-ion beam sputtering source to texture the surfaces of biological implant materials. Scanning electron microscopy was used to determine surface morphology changes of all materials after ion-texturing. Electron spectroscopy for chemical analysis was used to determine the effects of ion texturing on the surface chemical composition of some polymers. Liquid contact angle data were obtained for ion textured and untextured polymer samples. Results of tensile and fatigue tests of ion-textured metal alloys are presented. Preliminary data of tissue response to ion textured surfaces of some metals, polytetrafluoroethylene, alumina, and segmented polyurethane were obtained

Cell attachment on Ion-implanted titanium surface

Of outmost importance for the successful use of an implant is a good adhesion of the surrounding tissue to the biomaterial. In addition to the surface composition of the implant, the surface topography also influences the properties of the adherent cells. In the present investigation, ion implanted and untreated surfaces were compared for cell adhesion and spreading. The surface topography of the surfaces were analyzed using AFM and the cell studies with SEM. The results of our present investigation is indicative of the fact that ion implanted titanium surface offer better cell binding affinity compared to untreated/polished surface

Laser Textured Calcium Phosphate Bio-Ceramic Coatings on Ti-6Al-4V for Improved Wettability and Bone Cell Compatibility

The interaction at the surfaces of load bearing implant biomaterials with tissues and physiological fluids is an area of crucial importance to all kinds of medical technologies. To achieve the best clinical outcome and restore the function of the diseased tissue, several surface engineering strategies have been discussed by scientific community throughout the world. In the current work, we are focusing on one such technique based on laser surface engineering to achieve the appropriate surface morphology and surface chemistry. Here by using a pulsed and continuous wave laser direct melting techniques we synthesize three dimensional textured surfaces of calcium phosphate (Ca-P) based surface chemistry on Ti-6Al-4V. The influence of each processing type on the micro texture and phase evolution and thereby its associated effect on wettability, in vitro bioactivity, and in vitro biocompatibility are systematically discussed. For samples processed using the pulsed laser, it was realized that with increasing laser scan speed and laser pulse frequency there was a transition from surface textures with sharp circular grooves to surface textures with radial grooves and thereby improved hydrophilicity. For CW laser processing the results demonstrated improved hydrophilicity for the samples processed at 100 μm line spacing as compared to the samples processed at 200 μm line spacing. Owing to the importance of Si for cartilage and hard tissue repair, a preliminary effort for synthesizing Ca-P-SiO2 composite coating on Ti-6Al-4V surface were also conducted. As a future potential technique we also explored the Laser Interference Patterning (LIP) technique to achieve the textured surfaces and developed understanding on their wetting behavior. In the current work, by adjusting the laser processing parameters we were able to synthesize textured coatings with biocompatible phases. The in vitro bioactivity and in vitro vi biocompatibility of the coatings were proved by the precipitation of an apatite like phase following immersion in simulated body fluid (SBF), and increased proliferation and spreading of the MC3T3-E1 like cells. The results and understanding of the current research is encouraging in terms of looking at other bio-ceramic precursor compositions and laser process parameter window for synthesizing better textured biocompatible coatings