Cellular Response of Human Bone Marrow Derived Mesenchymal Stem Cells to Titanium Surfaces Implanted with Calcium and Magnesium Ions.

Surface characteristics and cellular response to titanium surfaces that had been implanted with calcium and magnesium ions using plasma immersion ion implantation and deposition (PIIID) were evaluated. Three different titanium surfaces were analyzed: a resorbable blast media (RBM) surface (blasted with hydroxyapatite grit), a calcium ion-implanted surface, and a magnesium ion-implanted surface. The surface characteristics were investigated by scanning electron microscopy (SEM), surface roughness testing, X-ray diffraction (XRD), and Auger electron spectroscopy (AES). Human bone marrow derived mesenchymal stem cells were cultured on the 3 different surfaces. Initial cell attachment was evaluated by SEM, and cell proliferation was determined using MTT assay. Real-time polymerase chain reaction (PCR) was used to quantify osteoblastic gene expression (i.e., genes encoding RUNX2, type I collagen, alkaline phosphatase, and osteocalcin). Surface analysis did not reveal any changes in surface topography after ion implantation. AES revealed that magnesium ions were present in deeper layers than calcium ions. The calcium ion- and magnesium ion-implanted surfaces showed greater initial cell attachment. Investigation of cell proliferation revealed no significant difference among the groups. After 6 days of cultivation, the expression of RUNX2 was higher in the magnesium ion-implanted surface and the expression of osteocalcin was lower in the calcium ion-implanted surface. In conclusion, ion implantation using the PIIID technique changed the surface chemistry without changing the topography. Calcium ion- and magnesium ion-implanted surfaces showed greater initial cellular attachment.

Magnetic, optical and structural property studies of Mn-doped ZnO nanosheets.

We report the synthesis of pure and Mn doped ZnO in the form of nanosheets using a simple and single step procedure involving a microwave assisted chemical method. As prepared Mn-doped ZnO nanosheets were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), ultra violet-visible (UV-Vis), Raman spectroscopy and magnetization measurements. The structural studies using XRD and TEM revealed the absence of Mn-related secondary phases and showed that Mn-doped ZnO comprise a single phase nature with wurtzite structure. FESEM and TEM micrographs show that the average diameter of Mn-ZnO assembled nanosheets is about approximately 50 nm, and the length of a Mn-doped ZnO nanosheet building block which is made up of thin mutilayered sheets is around approximately 300 nm. Concerning the Raman scattering spectra, the shift in peak position of E2 (high) mode toward low frequencies due to the Mn doping could be explained well by means of the spatial correlation model. Magnetic measurements showed that Mn-doped ZnO nanosheets exhibit ferromagnetic ordering at or above room temperature.

Bone response of Mg ion-implanted clinical implants with the plasma source ion implantation method.

OBJECTIVES: This study examined the bone response of magnesium (Mg) ion-implanted implants produced using a plasma source ion implantation method. MATERIALS AND METHODS: The surface characteristics were evaluated by scanning electron microscopy, Auger electron spectroscopy, X-ray photoelectron spectroscopy, and Rutherford backscattering spectroscopy. The screw-type titanium implants were treated with resorbable blasting media (RBM) and divided into one control group (RBM implants) and three test groups (Mg ion-implanted implants with different retained Mg doses). Twenty-four implants from each group were placed into the tibiae of 24 New Zealand white rabbits. After allowing 6 weeks for healing, the removal torque (RTQ) was measured and the implants were subjected to histomorphometric analysis. RESULTS: The surface roughness and surface morphology of the test groups were similar. The Mg ion-implanted implants with a 2.3 x 10(15) ions/cm(2) retained dose showed a significantly higher RTQ than the other implants. Histomorphometric analysis indicated that the bone contact of this group was superior to the other groups. CONCLUSION: The bone response of Mg ion-implanted implant showed results superior or similar to an RBM-treated implant. The optimal Mg ion concentration that induced the strongest osseointegration was approximately 9%.

Biomechanical measurements of calcium-incorporated oxidized implants in rabbit bone: effect of calcium surface chemistry of a novel implant.

BACKGROUND: In oral implantology there has been a general trend away from machine-turned minimally rough and acid-etched and blasted implants toward intermediary roughened surfaces. Mechanical interlocking at micron resolution is claimed to be the dominant reason for the fixation of such implants in bone. However, clinical demands for stronger and faster bone bonding to the implant (eg, in immediately loaded and compromised bone cases) have motivated the development of novel surfaces capable of chemical bonding. PURPOSE: The purpose of the present study is to investigate bone tissue reactions to a newly developed calciumincorporated oxidized implant. The specific aim is to assess the effect of calcium surface chemistry on the bone response. MATERIALS AND METHODS: Calcium (Ca) ion-incorporated implants were prepared by micro arc oxidation methods. Surface oxide properties were characterized by using various surface analytic techniques involving scanning electron microscopy, x-ray diffractometry, x-ray photoelectron spectroscopy, and optical interferometry. Twenty screw-shaped commercially pure (CP) titanium implants (10 turned implants [controls] and 10 Ca-incorporated implants [tests]) were inserted in the femoral condyles of 10 New Zealand White rabbits. RESULTS: After a healing period of 6 weeks, resonance frequency analyses and removal torque measurements of the Ca-incorporated oxidized implants demonstrated statistically significant improvements of implant integration with bone in comparison to machine-turned control implants (p = 0.013 and p = 0.005, respectively). CONCLUSIONS: The Ca-reinforced surface chemistry of the oxidized implants significantly improved bone responses in a rabbit model. The present study suggests that biochemical bonding at the bone-implant interface, in combination with mechanical interlocking, may play a dominant role in the fixation of Ca-incorporated oxidized implants in bone. The observed rapid and strong integration of test Ca implants may have clinical implications for immediate or early loading and improved performance in compromised bone.