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To simultaneously enhance the osteogenic and antibacterial properties of titanium, we introduced magnesium (Mg), silver (Ag), or both by using the plasma immersion ion implantation (PIII) technique, producing three PIII sample groups, namely, Mg-doped titanium (Mg-PIII), Ag-doped titanium (Ag-PIII), and Mg and Ag codoped titanium (Mg/Ag-PIII). The in vitro antibacterial efficacy of Mg/Ag-PIII group was about 7-10% higher than that of Ag-PIII. In vitro and in vivo results demonstrated that osteogenic property of Mg/Ag PIII group was better than that of Ag-PIII or Mg-PIII. It was believed that the galvanic effects between Mg and Ag NPs played a key role in facilitating the release of Mg but reducing the release of silver, answering for the selective performances of the Mg/Ag-PIII group over bacterial and mammalian cells. This study demonstrated that the integration of multiple functional elements could be realized by the dual-source PIII technique, and in this case, the antibacterial properties and osteogenic property of titanium could be balanced.

Prevention of implant loosening and infection is crucial to orthopedic and dental surgeries. In this work, the surface of stainless steel (SS) was modified by silver-sourced plasma immersion ion implantation (Ag-PIII). Metallic silver nanoparticles with various diameters and distributions were fabricated on the SS surfaces after treatment with Ag-PIII for 0.5 and 1.5 h, respectively. The osteogenic activity and antimicrobial properties of SS before and after Ag-PIII treatment were evaluated using in vitro and in vivo tests. The results demonstrated that Ag-PIII treatment not only promoted the antibacterial activity of SS but also enhanced the osteogenic differentiation of human bone marrow stromal cells.

Titanium implants possessing simultaneous osseointegration and antibacterial ability are desirable. In this work, three types of Zn/Ag micro-galvanic couples are fabricated on titanium by plasma immersion ion implantation to investigate the osseointegration and antibacterial effects as well as the involved mechanisms. The in vitro findings disclose enhanced proliferation, osteogenic differentiation, and gene expressions of the rat bone mesenchymal stem cells (rBMSCs), as well as good antibacterial ability on all three micro-galvanic couples. Excellent antimicrobial ability is also observed in vivo and the micro-CT and histological results reveal notable osseointegration in vivo despite the presence of bacteria. The Zn/Ag micro-galvanic couple formed on Zn/Ag dual-ion co-implanted titanium shows the best osseointegration as well as good antibacterial properties in vivo obtained from a rabbit tibia model. The difference among the three Zn/Ag micro-galvanic couples can be ascribed to the contact between the Ag NPs and Zn film, which affects the corrosion process. Our results indicate that the biological behavior can be controlled by the corrosion process of the Zn/Ag micro-galvanic couples.

Prevention of periprosthetic infection (PPI) by inhibiting biofilm formation on prostheses is crucial to orthopedic surgery. In this work, silver nanoparticles (Ag NPs) are fabricated in situ and immobilized on titanium by silver plasma immersion ion implantation (PIII). The anti-biofilm activity rendered by the immobilized Ag NPs is assessed using Staphylococcus epidermidis, a biofilm producing strain, in vitro and in vivo. The immobilized Ag NPs show no apparent cytotoxicity but reduce biofilm formation in vitro by inhibiting bacteria adhesion and icaAD transcription. The immobilized Ag NPs offer a good defense against multiple cycles of bacteria attack in vitro, and the mechanism is independent of silver release. Radiographic assessment, microbiological cultures, and histopathological results demonstrate the ability of the functionalized surface against bacterial infection to reduce the risk of implant-associated PPI.

Zinc (Zn) and silver (Ag) are co-implanted into titanium by plasma immersion ion implantation. A Zn containing film with Ag nanoparticles (Ag NPs) possessing a wide size distribution is formed on the surface and the corrosion resistance is improved due to the micro-galvanic couples formed by the implanted Zn and Ag. Not only are the initial adhesion, spreading, proliferation and osteogenic differentiation of rBMSCs observed from the Zn/Ag implanted Ti in vitro, but also bacteria killing is achieved both in vitro and in vivo. Electrochemical polarization and ion release measurements suggest that the excellent osteogenic activity and antibacterial ability of the Zn/Ag co-implanted titanium are related to the synergistic effect resulting from the long-range interactions of the released Zn ions and short-range interactions of the embedded Ag NPs. The Zn/Ag co-implanted titanium offers both excellent osteogenic activity and antibacterial ability and has large potential in orthopedic and dental implants.

Nanotube morphology has been previously applied to improve osseointegration in osteoporosis, but the osteogenic capability of the technique requires further improvements. This study aimed to investigate the effects of vacuum extraction on the loading of rhPDGF-BB on nanotube arrays as well as its effects on the osseointegration of ovariectomized (OVX) rats. More rhPDGF-BB protein particles aggregated on the nanotube surface and into the nanotube after vacuum extraction for 10min. The immobilized protein could be slowly released for at least 14days and still kept its biological activity. In vitro , the immobilized rhPDGF-BB enhanced cell adhesion, proliferation and osteogenic differentiation. In vivo , more rhPDGF-BB immobilized on the nanotube surface also promoted the osseointegration. These results suggest that the enhanced immobilization of rhPDGF-BB on nanotube arrays can potentially be used in the future as an implant surface modification strategy in dental and orthopedic applications in osteoporotic patients. From the Clinical Editor This study presents convincing evidence that enhanced immobilization of recombinant human PDGF-BB protein particles on nanotubes lead to improved osteogenic differentiation in an experimental system. When used as a surface modification strategy for dental or orthopedic implants, this method was able to promote osseointegration even in an osteoporotic animal model, raising the likelihood for potential future clinical applications.

In this work, zero valent iron nanoparticles (Fezero-NPs) and iron oxide nanoparticles (Feox-NPs) were synthesized at the subsurface and surface regions of titanium oxide coatings (TOCs) by plasma immersion ion implantation. This novel Fe-NPs/TOC system showed negligible iron releasing, great electron storage capability and excellent cytocompatibility in vitro. Importantly, the system showed selective antibacterial ability which can kill Staphylococcus aureus under dark conditions but has no obvious antibacterial effect against Escherichia coli. Owing to a bipolar Schottky barrier between Fezero-NPs/TOC and Fezero-NPs/Feox-NPs, electrons could be captured by the Fezero-NPs bounded at the subsurface region of the coating. This electron storage capability of the Fe-NPs/TOC system induced extracellular electron transportation and accumulation of adequate valence-band holes (h(+)) at the external side, which caused oxidation damage to S. aureus cells in the dark. No obvious biocide effect against E. coli resulted from lack of electron transfer ability between E. coli and substrate materials. This work may open up a novel and controlled strategy to design coatings of implants with antibacterial ability and cytocompatibility for medical applications.

As an implantable material, carbon-fiber-reinforced polyetheretherketone (CFRPEEK) possesses an adjustable elastic modulus similar to that of cortical bone and is a prime candidate to replace metallic surgical implants. However, the bioinertness and poor osteogenic properties of CFRPEEK limit its clinical application as orthopedic implants. In this work, titanium ions are introduced energetically into CFRPEEK by plasma immersion ion implantation (PIII). Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) reveal the formation of nanopores with the side wall and bottom embedded with ∼20 nm TiO2 nanoparticles on the CFRPEEK surface. Nanoindentation measurements confirm the stability and improved elastic resistance of the structured surfaces. In vitro cell adhesion, viability assay, and real-time PCR analyses disclose enhanced adhesion, proliferation, and osteo-differentiation of rat bone mesenchymal stem cells (bMSCs). The multilevel structures on CFRPEEK also exhibit partial antibacterial activity to Staphylococcus aureus and Escherichia coli. Our results indicate that a surface with multifunctional biological properties can be produced by multilevel surface engineering and application of CFRPEEK to orthopedic and dental implants can be broadened and expedited based on this scheme.

Titanium (Ti) and its alloys are widely used as orthopedic and dental implants. In this work, zinc (Zn) was implanted into oxalic acid etched titanium using plasma immersion ion implantation technology. Scanning electron microscopy and X-ray photoelectron spectroscopy were used to investigate the surface morphology and composition of Zn-implanted titanium. The results indicate that the depth profile of zinc in Zn-implanted titanium resembles a Gaussian distribution, and zinc exists in the form of ZnO at the surface whereas in the form of metallic Zn in the interior. The Zn-implanted titanium can significantly stimulate proliferation of osteoblastic MC3T3-E1 cells as well as initial adhesion, spreading activity, ALP activity, collagen secretion and extracellular matrix mineralization of the rat mesenchymal stem cells. The Zn-implanted titanium presents partly antibacterial effect on both Escherichia coli and Staphylococcus aureus. The ability of the Zn-implanted titanium to stimulate cell adhesion, proliferation and differentiation as well as the antibacterial effect on E. coli can be improved by increasing implantation time even to 2 h in this work, indicating that the content of zinc implanted in titanium can easily be controlled within the safe concentration using plasma immersion ion implantation technology. The Zn-implanted titanium with excellent osteogenic activity and partly antibacterial effect can serve as useful candidates for orthopedic and dental implants.

This paper introduces a novel thin silicon rotor turned gyroscope (SRTG). With a micro motor driving the rotor and two pairs of torsion bars and a gimbal ring realizing dynamical tuning, this gyroscope inherits the structure and working principle of the dynamically tuned gyroscope (DTG). The torsion bars, gimbal ring, rotor, annunciator and torquer are processed by micro-mechanical technology. The declination of rotor is sensed by differential capacitances. The rotor is rebalanced by electrostatic forces. In this paper, the details about the structure and working principle of SRTG is presented, the block diagram of the circuit in SRTG is discussed. Experiments are done on one sensitive direction of SRTG, and the curve is given, proved the feasibility.

Electrostatic driving and capacitive detection is widely used in micro hemispheric shell resonators (HSR). The capacitor gap distance is a dominant factor for the initial capacitance, and affects the driving voltage and sensitivity. In order to decrease the equivalent gap distance, a micro HSR with annular electrodes fabricated by a glassblowing method was developed. Central and annular cavities are defined, and then the inside gas drives glass softening and deformation at 770 °C. While the same force is applied, the deformation of the hemispherical shell is about 200 times that of the annular electrodes, illustrating that the deformation of the electrodes will not affect the measurement accuracy. S-shaped patterns on the annular electrodes and internal-gear-like patterns on the hemispherical shell can improve metal malleability and avoid metal cracking during glass expansion. An arched annular electrode and a hemispheric shell are demonstrated. Compared with HSR with a spherical electrode, the applied voltage could be reduced by 29%, and the capacitance could be increased by 39%, according to theoretical and numerical calculation. The surface roughness of glass after glassblowing was favorable (Rq = 0.296 nm, Ra = 0.217 nm). In brief, micro HSR with an annular electrode was fabricated, and its superiority was preliminarily confirmed.

Silver plasma immersion ion implantation was used to decorate silver nanoparticles (Ag NPs) on tantalum oxide (TO) coatings. The coatings acted against bacterial cells (Staphylococcus epidermidis) in the dark by disrupting their integrity. The action was independent of silver release and likely driven by the electron storage capability of the Schottky barriers established at the interfaces between Ag NPs and the TO support. Moreover, no apparent side effect on the adhesion and differentiation of rat bone mesenchymal stem cells was detected when using Ag NPs-modified TO coatings. These results demonstrate that decoration of tantalum oxide using Ag NPs could be a promising procedure for improving the antibacterial properties for orthopedic and dental implants.

This paper focuses on an optimal quadrature error correction method for the dual-mass MEMS gyroscope, in order to reduce the long term bias drift. It is known that the coupling stiffness and demodulation error are important elements causing bias drift. The coupling stiffness in dual-mass structures is analyzed. The experiment proves that the left and right masses’ quadrature errors are different, and the quadrature correction system should be arranged independently. The process leading to quadrature error is proposed, and the Charge Injecting Correction (CIC), Quadrature Force Correction (QFC) and Coupling Stiffness Correction (CSC) methods are introduced. The correction objects of these three methods are the quadrature error signal, force and the coupling stiffness, respectively. The three methods are investigated through control theory analysis, model simulation and circuit experiments, and the results support the theoretical analysis. The bias stability results based on CIC, QFC and CSC are 48 °/h, 9.9 °/h and 3.7 °/h, respectively, and this value is 38 °/h before quadrature error correction. The CSC method is proved to be the better method for quadrature correction, and it improves the Angle Random Walking (ARW) value, increasing it from 0.66 °/√h to 0.21 °/√h. The CSC system general test results show that it works well across the full temperature range, and the bias stabilities of the six groups’ output data are 3.8 °/h, 3.6 °/h, 3.4 °/h, 3.1 °/h, 3.0 °/h and 4.2 °/h, respectively, which proves the system has excellent repeatability.

Described in this paper is a new Microelectromechanical Hybrid Gyroscope(MHG), with advantages not only in the potentiality of achieving the high precision like the traditional dynamically tuned gyroscope(DTG), but also in small size and low cost like the Silicon Micromachined Gyroscope(SMG). The transfer coefficient of the moment is derived, with influence factors analyzed. A new tuning method which tuned the microelectromechanical hybrid gyroscope by negative stiffness effectiveness of the moment is adopted. An interface circuit is researched, the sensitivity equation of the interface circuit is deduced and a decoupled rebalancing control loop circuit is researched. Finally, on this basis, the prototype of the MHG is achieved. The experiment results prove that the new tuning method by negative stiffness effectiveness of the moment is feasible, and the designs of the interface circuit and rebalancing control loop are proper. The preliminary performance test of the prototype shows that the scale factor is 1.42mV/°/s, the scale factor non-linearity 2.47%and the maximum rate °200°/s, which proves that the fundamental principle of the MHG is feasible.

Yu Zhu,1,* Huiliang Cao,2,* Shichong Qiao,1,* Manle Wang,2,3 Yingxin Gu,1 Huiwen Luo,1 Fanhao Meng,2 Xuanyong Liu,2 Hongchang Lai1 1Department of Oral and Maxillofacial Implantology, Shanghai Key Laboratory of Stomatology, Shanghai Ninth People’s Hospital, School of Medicine, Shanghai Jiao Tong University, 2State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 3School of Materials Engineering, Shanghai University of Engineering Science, Shanghai, People’s Republic of China *These authors contributed equally tothis work Abstract: A versatile strategy to endow dental implants with long-term antibacterial ability without compromising the cytocompatibility is highly desirable to combat implant-related infection. Silver nanoparticles (Ag NPs) have been utilized as a highly effective and broad-spectrum antibacterial agent for surface modification of biomedical devices. However, the high mobility and subsequent hazardous effects of the particles on mammalian cells may limit its practical applications. Thus, Ag NPs were immobilized on the surface of sand-blasted, large grit, and acid-etched (SLA) titanium by manipulating the atomic-scale heating effect of silver plasma immersion ion implantation. The silver plasma immersion ion implantation-treated SLA surface gave rise to both good antibacterial activity and excellent compatibility with mammalian cells. The antibacterial activity rendered by the immobilized Ag NPs was assessed using Fusobacterium nucleatum and Staphylococcus aureus, commonly suspected pathogens for peri-implant disease. The immobilized Ag NPs offered a good defense against multiple cycles of bacteria attack in both F. nucleatum and S. aureus, and the mechanism was independent of silver release. F. nucleatum showed a higher susceptibility to Ag NPs than S. aureus, which might be explained by the presence of different wall structures. Moreover, the immobilized Ag NPs had no apparent toxic influence on the viability, proliferation, and differentiation of rat bone marrow mesenchymal stem cells. These results demonstrated that good bactericidal activity could be obtained with very small quantities of immobilized Ag NPs, which were not detrimental to the mammalian cells involved in the osseointegration process, and promising for titanium-based dental implants with commercial SLA surfaces. Keywords: silver nanoparticles, surface modification, antibacterial effects, cytotoxicity, plasma immersion ion implantation

This paper proposes an electrostatic stiffness correction method for the quadrature error (QUER) in a decoupled dual-mass gyroscope structure. The QUER is caused by the imperfections during the structure manufacturing process, and the two masses usually have different QUERs. The harm contribution to the Coriolis signal is analyzed and quantified. The generating forms of QUER motion in both masses are analyzed, the correction electrodes’ working principle is introduced, and a single mass individual correction method is proposed. The QUER stiffness correction system is designed based on a PI controller, and the experiments are arranged to verify the theoretical analysis. The bias stability decreases from 2.06 to 0.64 deg/h after the QUER correction, and the parameters of scale factor such as nonlinearly, asymmetry, and repeatability, reduce from 143, 557, and 210 ppm to 84, 242, and 175 ppm, respectively.

Finding approaches to control the elementary processes of plasma-solid interactions and direct the fluxes of matter at nano-scales becomes an important aspect in science. This letter reports that, by taking advantages of the spacing characteristics of discrete TiO2 nanotube arrays, the flying trajectories and the subsequent implantation and deposition manner of energetic carbon ions can be directed and controlled to fabricate hollow conical arrays. The study provides an alternative method for plasma nano-manufacturing.

This paper investigates temperature compensation methods used for the scale factor and bias of the MEMS gyroscope within the temperature range from − 40°C to 60°C. The structure and periphery monitor circuit are introduced. Then the determinant elements of the MEMS gyroscope's scale factor are analysed and the results indicate that scale factor is directly proportional to drive amplitude and sense loop gain and is inversely proportional to the frequency gap between two modes. After that, the compensation methods are proposed, the thermal resistor's positive temperature coefficient (tempco) is utilized to calibrate the scale factor's tempco through regulating the drive mode amplitude and the sense loop gain, and each method is applied respectively and the results are contrasted. The test results of the two specimens express that the most effective compensation method could decrease the scale factor's tempco from 693ppm/°C (640ppm/°C) to 250ppm/°C (257ppm/°C), improving it by 63.9% (59.8%). Finally, a method of declining bias's tempco is investigated and implemented after scale factor compensation. A summator with a thermal resistor is utilized at the output level and decreases the bias's tempco from 103.89°/h/°C (100.78°/h/°C) to 9.70°/h/°C (12°/h/°C) improving it by 90.7% (88%). Repeat tests are performed based on two specimens to prove the repeatability and reproducibility of the methods.