Modification of surface morphology of UHMWPE for biomedical implants

Ion-Beam-Based Nanofabrication; San Francisco, CA; United States; 10 April 2007 through 12 April 2007Ultra High Molecular Weight Polyethylene (UHMWPE) samples were implanted with metal and metal-gas hybrid ions (Ag, Ag+N, C+H, C+H+Ar, Ti+O) by using improved MEVVA Ion implantation technique [1,2]. An extraction voltage of 30 kV and influence of 1017 ions/cm2 were attempted in this experiment, to change their surface morphologies in order to understand the effect of ion implantation on the surface properties of UHMWPEs. Characterizations of the implanted samples with RBS , ATR - FTIR, spectra were compared with the un-implanted ones . Implanted and unimplanted samples were also thermally characterized by TGA and DSC. It was generally observed that C-H bond concentration seemed to be decreasing with ion implantation and the results indicated that the chain structure of UHMWPE were changed and crosslink density and polymer crystallinity were increased compared to unimplanted ones resulting in increased hardness. It was also observed that nano size cracks (approx.10nm) were significantly disappeared after Ag implantation, which also has an improved antibacterial effect. Contact angle measurements showed that wettability of samples increased with ion implantation. Results showed that metal and metal+gas hybrid ion implantation could be an effective way to improve the surface properties of UHMWPE to be used in hip and knee prosthesis.Center for Irradiation of Materials, Alabama A&M Universit

Structure effects in heavy-ion transfer reaction to the continuum

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Physics, 1982.MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE.Includes bibliographical references.by Daryush Ila.M.S

Patterned adhesion of cells

Symposium on Ion-Beam-Based Nanofabrication held at the 2007 MRS Spring Meeting -- APR 10-12, 2007 -- San Francisco, CAWOS: 000250475100010It is well known that silver deposition avoids bacterial growth and inhibits the natural process of attachment of connective tissue to biocompatible materials in vivo. We have completed a five year investigation of the precise spatial control of cell growth on glassy polymeric carbon implanted with silver using ion beam techniques, and the persistence of the inhibitory effect on cell growth. Long term inhibition of cell growth on GPC is a desirable improvement on current cardiac implants and other biocompatible materials placed in the blood stream. We have used implanted silver ions near the surface of GPC to completely inhibit cell attachment and adhesion. Cells attach and strongly adhere to areas close to the silver implanted surfaces. Patterned ion implantation permits precise control of tissue growth on GPC and other biocompatible substrates. Cell growth limited to micrometric patterns on a substrate may be useful for in vitro studies of associated biological processes in an otherwise identical environment. The patterned inhibition of cell attachment persists for periods of time significant relative to typical implant lifetimes.Center for Irradiation of Materials, Alabama AM University; National Science FoundationNational Science Foundation (NSF) [EPS-0447675]Research sponsored by the Center for Irradiation of Materials, Alabama A&M University and by National Science Foundation under Grant No. EPS-0447675

Fluoropolymer Studies for Radiation Dosymetry

The polymers Tetrafluoroethylene-hexa-fluoropropylene (FEP) and Tetrafluoroethylene-per-fluoromethoxyethelene (PFA) are normally used as anti-adherent coatings and can also be applied for several applications in research. For example, they can be used as radiation dosimeters for X-ray and gamma photons, electrons, protons and other ionazing particles. In order to determine radiation induced damage, that can compromise applications in dosimetry, FEP and PFA films were bombarded with protons of 1 MeV at fluences from 1 × 10 11 protons/cm 2 to 1 × 10 16 protons/cm 2 . During the bombardment, the chemical species emission was monitored with a Residual Gas Analyzer (RGA), and results show that the CF3 radical is the specie preferentially emitted. The bombarded films were also analyzed with Optical Absorption Photospectrometry (OAP) which shows quantitative chemically specific evidence of the damage caused by the proton bombardment. Our results show that damage to polymers is detectable for all fluences used in this work, but damage that can compromise applications in dosimetry occurs only for fluences greater than 1 × 10 14 protons/cm 2

The Effect of Ag and Ag plus N Ion Implantation on Cell Attachment Properties

20th International Conference on Application of Accelerators in Research and Industry -- AUG 10-15, 2008 -- Ft Worth, TXWOS: 000265828500115Implanted biomedical prosthetic devices are intended to perform safely, reliably and effectively in the human body thus the materials used for orthopedic devices should have good biocompatibility. Ultra High Molecular Weight Poly Ethylene (UHMWPE) has been commonly used for total hip joint replacement because of its very good properties. In this work, UHMWPE samples were Ag and Ag+N ion implanted by using the Metal-Vapor Vacuum Arc (MEVVA) ion implantation technique. Samples were implanted with a fluency of 1017 ion/cm2 and extraction voltage of 30 kV. Rutherford Backscattering Spectrometry (RBS) was used for surface studies. RBS showed the presence of Ag and N on the surface. Cell attachment properties investigated with model cell lines (L929 mouse fibroblasts) to demonstrate that the effect of Ag and Ag+N ion implantation can favorably influence the surface of UHMWPE for biomedical applications. Scanning electron microscopy (SEM) was used to demonstrate the cell attachment on the surface. Study has shown that Ag+N ion implantation represents more effective cell attachment properties on the UHMWPE surfaces.Univ N Texas, Sandia Natl La

Modification of surface morphology of UHMWPE for biomedical implants

Ion-Beam-Based Nanofabrication; San Francisco, CA; United States; 10 April 2007 through 12 April 2007Ultra High Molecular Weight Polyethylene (UHMWPE) samples were implanted with metal and metal-gas hybrid ions (Ag, Ag+N, C+H, C+H+Ar, Ti+O) by using improved MEVVA Ion implantation technique [1,2]. An extraction voltage of 30 kV and influence of 1017 ions/cm2 were attempted in this experiment, to change their surface morphologies in order to understand the effect of ion implantation on the surface properties of UHMWPEs. Characterizations of the implanted samples with RBS , ATR - FTIR, spectra were compared with the un-implanted ones . Implanted and unimplanted samples were also thermally characterized by TGA and DSC. It was generally observed that C-H bond concentration seemed to be decreasing with ion implantation and the results indicated that the chain structure of UHMWPE were changed and crosslink density and polymer crystallinity were increased compared to unimplanted ones resulting in increased hardness. It was also observed that nano size cracks (approx.10nm) were significantly disappeared after Ag implantation, which also has an improved antibacterial effect. Contact angle measurements showed that wettability of samples increased with ion implantation. Results showed that metal and metal+gas hybrid ion implantation could be an effective way to improve the surface properties of UHMWPE to be used in hip and knee prosthesis.Center for Irradiation of Materials, Alabama A&M Universit

Modification of surface morphology of UHMWPE for biomedical implants

Symposium on Ion-Beam-Based Nanofabrication held at the 2007 MRS Spring Meeting -- APR 10-12, 2007 -- San Francisco, CAWOS: 000250475100012Ultra High Molecular Weight Polyethylene (UHMWPE) samples were implanted with metal and metal-gas hybrid ions (Ag, Ag+N, C+H, C+H+Ar, Ti+O) by using improved MEVVA Ion implantation technique [1,2]. An extraction voltage of 30 kV and influence of 1017 ions/cm2 were attempted in this experiment. to change their surface morphologies in order to understand the effect of ion implantation on the surface properties of UHMWPEs. Characterizations of the implanted samples with RBS, ATR - FTIR, spectra were compared with the un-implanted ones. Implanted and unimplanted samples were also thermally characterized by TGA and DSC. It was generally observed that C-H bond concentration seemed to be decreasing with ion implantation and the results indicated that the chain structure of UHMWPE were changed and crosslink density and polymer crystallinity were increased compared to unimplanted ones resulting in increased hardness. It was also observed that nano size cracks (approx. 10nm) were significantly disappeared after Ag implantation, which also has an improved antibacterial effect. Contact angle measurements showed that wettability of samples increased with ion implantation. Results showed that metal and metal+gas hybrid ion implantation could be an effective way to improve the surface properties of UHMWPE to be used in hip and knee prosthesis.Center for Irradiation of Materials, Alabama AM UniversityThis work was supported by the Center for Irradiation of Materials, Alabama A&M University