Optimization of Cell Adhesion on Mg Based Implant Materials by Pre-Incubation under Cell Culture Conditions

Magnesium based implants could revolutionize applications where orthopedic implants such as nails, screws or bone plates are used because they are load bearing and degrade over time. This prevents a second surgery to remove conventional implants. To improve the biocompatibility we studied here if and for how long a pre-incubation of the material under cell culture conditions is favorable for cell attachment and proliferation. For two materials, Mg and Mg10Gd1Nd, we could show that 6 h pre-incubation are already enough to form a natural protective layer suitable for cell culture.     

Structural Effects on the Adhesive Properties of Butadiene/Styrene Radial Teleblock Copolymers

The effects of butadiene/styrene ratio, monomer distribution, and molecular weight distribution and branching on the pressure sensitive adhesive properties of butadiene/ styrene radial teleblock copolymers are reported. Styrene content of polymers with varying structures shows a close relation with tack response, and styrene content and structure affect solution viscosity and shear adhesion. When part of the styrene is incorporated into the polybutadiene segment to yield a block progressively enriched in styrene (tapered block), solution viscosity and shear adhesion are reduced. When the butadiene segment is replaced by a block of randomly copolymerized butadiene and styrene, the polymers provide lower solution viscosities and shear adhesion but unchanged tack.

The molecular weight distribution of the radial teleblock polymers can vary from broad, highly branched compositions to narrow molecular weight distributions of almost Iinear polymers. The latter have relatively high solution viscosity and low shear adhesion, whereas the former polymers produce moderate solution viscosity but high shear adhesion. Tack is generally unaffected.     

Vision implants:An electrical device will bring light to the blind

Cochlear implant has been successfully applied in clinic. Recent research indicates vision implants may be the potential way to restore sight for the blind. Here, principle and common structure of vision implants are introduced. Main vision approaches of retinal, optic nerve, and cortical prosthesis are reviewed. In our progress, electrical response at visual cortex is recorded, when penetrating electrodes stimulate rabbit optic nerve, vision implants based on optic nerve stimulator chip （ONSC） and Chipcon radio frequency （RF） chip are under developing. Despite several obstacles to overcome, promising results in animal and human experiments give scientists confidence that artificial vision implants will bring light to the blind in the near future.     

Position adjustment method and distance estimation method of magnetic field supply and detection unit for magnetic hyperthermia

In magnetic hyperthermia, the temperature and localization of a ferromagnetic implant in a tumor region is vital in determining the effectiveness of therapeutic heating. We have developed a noninvasive wireless temperature measurement method by utilizing the magnetic permeability property of a ferromagnetic implant with low Curie temperature (FILCT) that varies with the temperature. In clinical settings, when the FILCT is injected into a tumor region, the position of the FILCT is expected to deviate from the central axis of the heating coil (drive coil). When it deviates, the magnetic flux density applied to the FILCT decreases, thus causing difficulty in detecting the temperature of FILCT via a pickup coil and heating of the FILCT at a constant treatment temperature. Therefore, to adjust the magnetic field supply and detection (MFSD) unit to be directly above the FILCT, we propose a position adjustment method by referring to three voltages induced in three pickup coils symmetrically installed inside the drive coil. By using the average value of the three voltages, we also propose a method to estimate the distance between the MFSD unit and the FILCT, which is required for wireless thermometry and determination of the optimal energy applied. The proposed methods are experimentally examined by a verification system.     

Influence of argon-ion bombardment of titanium surfaces on the cell behavior

Several studies in vitro and in vivo accomplished in dental implants have demonstrated that the chemical and physical properties of biomaterials are able to regulate the initial tecidual response around the implant. This tecidual response depends directly on the hydrophily, roughness, texture and chemical composition of the surface. Plasma treatment can be used to improve the surface properties of commercial pure Ti, in order to create different surface topographies, changes in roughness, and modifications in the surface wettability. In this study a surface modification in titanium Cp degree II was carried out, through the plasma treatment and using argon-ion bombardment. A comparison of surface properties and their influence on the cells behavior was also accomplished, besides the quantification of surface roughness, wettability and cellular proliferation. The results showed that the argon-ion bombardment influences the surface energy value, surface roughness and the surface topography of Ti materials. These parameters influence the cellular proliferation process.     

Cell Adhesion and Interactions with Biomaterials

The related phenomena of biocompatibility and biodegradation are of major concern in the selection of synthetic polymers for use as implantable biomedical devices. These properties are largely determined by the consequences of the cellular interactions that occur at the polymer/tissue interface during inflammation. Using an in vivo cage implant system, in conjunction with surface analysis techniques, we have investigated the variation in the cellular events that occurred on a polyetherure-thaneurea and a cytotoxic polyvinyl chloride). Quantitative and qualitative information that describe the cellular response to polymer implantation will be presented. From the results, a chronological sequence has been established which suggests that the important events follow cellular adhesion, and include cell spreading over a polymer surface accompanied by lysosomal degranulation of the adherent cells.     

Introducing a Semi-Coated Model to Investigate Antibacterial Effects of Biocompatible Polymers on Titanium Surfaces

Peri-implant infections from bacterial biofilms on artificial surfaces are a common threat to all medical implants. They are a handicap for the patient and can lead to implant failure or even life-threatening complications. New implant surfaces have to be developed to reduce biofilm formation and to improve the long-term prognosis of medical implants. The aim of this study was (1) to develop a new method to test the antibacterial efficacy of implant surfaces by direct surface contact and (2) to elucidate whether an innovative antimicrobial copolymer coating of 4-vinyl-N-hexylpyridinium bromide and dimethyl(2-methacryloyloxyethyl) phosphonate (VP:DMMEP 30:70) on titanium is able to reduce the attachment of bacteria prevalent in peri-implant infections. With a new in vitro model with semi-coated titanium discs, we were able to show a dramatic reduction in the adhesion of various pathogenic bacteria (Streptococcus sanguinis, Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis), completely independently of effects caused by soluble materials. In contrast, soft tissue cells (human gingival or dermis fibroblasts) were less affected by the same coating, despite a moderate reduction in initial adhesion of gingival fibroblasts. These data confirm the hypothesis that VP:DMMEP 30:70 is a promising antibacterial copolymer that may be of use in several clinical applications.     

CR摄影技术在皮下埋植剂取出术中的应用价值

目的探讨CR摄影技术在皮下埋植剂取出术中的应用价值。方法在对584例育龄妇女进行左炔诺孕酮硅胶棒皮下埋植避孕剂(简称皮下埋植剂)的取出术中,有12例在取出时,出现取出困难。取出前常规消毒,在受术者的上臂内缘皮肤触摸,能触及皮下埋植剂,然后在上臂内侧缘肘关节上方3.0cm处皮肤上做一切口,进行皮下埋植剂的取出术,取出1根后,另1根反复寻找仍不见皮下埋植剂,然后拍上臂正、侧位CR片。结果在受术者上臂内侧缘肘关节上方3.0cm肌层深0.6cm处可见一纵形长约4.5cm直径0.3cm的管状阴影,长度直径均符合皮下埋植剂。结论 CR摄影技术能准确定位皮下埋植剂,尤其是侧位片定位更为准确。使手术医生能顺利取出皮下埋植剂,减少受术者痛苦,因此有推广价值。     

A review of surface topographical modification strategies of 3Y-TZP: Effect in the physicochemical properties,microstructure, mechanical reliability,and biological response

The development of zirconia dental implants has become increasingly popular over the last years due to the outstanding mechanical properties, superior aesthetic appearance and high biocompatibility of this material. However, premature implant failure as a result of an incomplete osseointegration still represents a major concern. In this sense, surface modifications have been applied to dental zirconia to improve the biological interactions of the implant with the surrounding tissue. Nevertheless, surface modification of zirconia is challenging due to the formation of a monoclinic phase associated with ageing and loss of mechanical integrity. This review focuses on the most common surface topographical modification strategies currently applied to zirconia, namely grinding, sandblasting, chemical etching and laser treatment. A comprehensive and comparative analysis has been performed to assess the effects of these techniques on the physicochemical properties, mechanical performance, hydrothermal degradation behavior and biological response of the modified surfaces.