Enhanced osteogenic and antibacterial properties of titanium implant surface modified with Zn-incorporated nanowires: Preclinical in vitro and in vivo investigations.

OBJECTIVE: This study aimed to synthesize zinc-incorporated nanowires structure modified titanium implant surface (Zn-NW-Ti) and explore its superior osteogenic and antibacterial properties in vitro and in vivo. MATERIALS AND METHODS: Zn-NW-Ti was synthesized via displacement reactions between zinc sulfate solutions and the titanium (Ti) surface, which was pretreated by hydrofluoric acid etching and hyperthermal alkalinization. The physicochemical properties of the Zn-NW-Ti surface were examined. Moreover, the biological effects of Zn-NW-Ti on MC3T3-E1 cells and its antibacterial property against oral pathogenic bacteria (Staphylococcus aureus, Porphyromonas gingivalis, and Actinobacillus actinomycetemcomitans) compared with sandblasted and acid-etched Ti (SLA-Ti) and nanowires modified Ti (NW-Ti) surface were assessed. Zn-NW-Ti and SLA-Ti modified implants were inserted into the anterior extraction socket of the rabbit mandible with or without exposure to the mixed bacterial solution (S. aureus, P. gingivalis, and A. actinomycetemcomitans) to investigate the osteointegration and antibacterial performance via radiographic and histomorphometric analysis. RESULTS: The Zn-NW-Ti surface was successfully prepared. The resultant titanium surface appeared as a nanowires structure with hydrophilicity, from which zinc ions were released in an effective concentration range. The Zn-NW-Ti surface performed better in facilitating the adhesion, proliferation, and differentiation of MC3T3-E1 cells while inhibiting the colonization of bacteria compared with SLA-Ti and NW-Ti surface. The Zn-NW-Ti implant exhibited enhanced osseointegration in vivo, which was attributed to increased osteogenic activity and reduced bacterial-induced inflammation compared with the SLA-Ti implant. CONCLUSIONS: The Zn-incorporated nanowires structure modified titanium implant surface exhibited improvements in osteogenic and antibacterial properties, which optimized osteointegration in comparison with SLA titanium implant surface.

Surface characteristics and in vitro biocompatibility of titanium preserved in a vitamin C-containing saline storage solution.

The purpose of this study is to explore a storage solution for titanium implants and investigate its osteogenic properties. The commercial pure titanium (cp-Ti) surface and double-etched (SLA) titanium surface specimens were preserved in air, saline, 10 mM Vitamin C (VitC)-containing saline and 100 mM VitC-containing saline storage solutions for 2 weeks. The surface microtopography of titanium was observed by scanning electron microscopy (SEM), the surface elemental compositions of the specimens were analyzed by Raman and X-ray photoelectron spectroscopy (XPS), and water contact angle and surface roughness of the specimens were tested. The protein adsorption capacity of two titanium surfaces after storage in different media was examined by BCA kit. The MC3T3-E1 osteoblasts were cultured on two titanium surfaces after storage in different media, and the proliferation, adhesion and osteogenic differentiation activity of osteoblasts were detected by CCK-8, laser confocal microscope (CLSM) and Western blot. The SEM results indicated that the titanium surfaces of the air group were relatively clean while scattered sodium chloride or VitC crystals were seen on the titanium surfaces of the other three groups. There were no significant differences in the micromorphology of the titanium surfaces among the four groups. Raman spectroscopy detected VitC crystals on the titanium surfaces of two experimental groups. The XPS, water contact angle and surface roughness results suggested that cp-Ti and SLA-Ti stored in 0.9% NaCl and two VitC-containing saline storage solutions possessed less carbon contamination and higher surface hydrophilicity. Moreover, the protein adsorption potentials of cp-Ti and SLA-Ti surfaces were significantly improved under preservation in two VitC-containing saline storage solutions. The results of in vitro study showed that the preservation of two titanium surfaces in 100 mM VitC-containing saline storage solution upregulated the cell adhesion, proliferation, osteogenic related protein expressions of MC3T3-E1 osteoblasts. In conclusion, preservation of cp-Ti and SLA-Ti in 100 mM VitC-containing saline storage solution could effectively reduce carbon contamination and enhance surface hydrophilicity, which was conducive to osteogenic differentiation of osteoblasts.

[Investigation and analysis of the current situation of dental technical professionals in Shanghai medical institutions].

PURPOSE: To investigate the current situation of dental technical personnel team in medical institutions in Shanghai, and to provide reference for the construction of dental technical discipline and development of dental personnel team in the National Center for Stomatology (Shanghai). METHODS: Random sample questionnaire and expert interviews were used to find out the awareness, satisfaction and improvement suggestions of dental technicians among physicians, nursing and medical technicians in medical institutions in Shanghai. RESULTS: Among the positions engaged in by dental technicians, dental prosthetic technician, dental radiology technician and laboratory technician were the three most important positions at present, 62.3% of doctors and nurses were satisfied with the work of dental technicians, while 56.2% of dental medical technicians were generally or relatively unsatisfied with their current work. CONCLUSIONS: It is necessary to increase training and education opportunities for dental technicians, improve the talent echelon, introduce high-level talents, improve the working environment and treatment, broaden promotion channels, strengthen communication and exchange with medical care, and build a first-class medical technical personnel team that is compatible with the clinical level of stomatology.

Osteogenic and anti-inflammatory effects of SLA titanium substrates doped with chitosan-stabilized selenium nanoparticles via a covalent coupling strategy.

Osseointegration is a prerequisite for the function of dental implants, and macrophage-dominated immune responses triggered by implantation determine the outcome of ultimate bone healing mediated by osteogenic cells. The present study aimed to develop a modified titanium (Ti) surface by covalently immobilizing chitosan-stabilized selenium nanoparticles (CS-SeNPs) to sandblasted, large grit, and acid-etched (SLA) Ti substrates and further explore its surface characteristics as well as osteogenic and anti-inflammatory activities in vitro. CS-SeNPs were successfully prepared by chemical synthesis and characterized their morphology, elemental composition, particle size, and Zeta potential. Subsequently, three different concentrations of CS-SeNPs were loaded to SLA Ti substrates (Ti-Se1, Ti-Se5, and Ti-Se10) using a covalent coupling strategy, and the SLA Ti surface (Ti-SLA) was used as a control. Scanning electron microscopy images revealed different amounts of CS-SeNPs, and the roughness and wettability of Ti surfaces were less susceptible to Ti substrate pretreatment and CS-SeNP immobilization. Besides, X-ray photoelectron spectroscopy analysis showed that CS-SeNPs were successfully anchored to Ti surfaces. The results of in vitro study showed that the four as-prepared Ti surfaces exhibited good biocompatibility, with Ti-Se1 and Ti-Se5 groups showing enhanced adhesion and differentiation of MC3T3-E1 cells compared with the Ti-SLA group. In addition, Ti-Se1, Ti-Se5, and Ti-Se10 surfaces modulated the secretion of pro-/anti-inflammatory cytokines by inhibiting the nuclear factor kappa B pathway in Raw 264.7 cells. In conclusion, doping SLA Ti substrates with a modest amount of CS-SeNPs (1-5 mM) may be a promising strategy to improve the osteogenic and anti-inflammatory activities of Ti implants.

miR-497 promotes the migration and invasion of human medulloblast Daoy cell line through targeted regulation of ARHGDIA in vitro.

OBJECTIVES: To further investigate the effects of miR-497 on the biological behavior of human medulloblastoma cell line in vitro. METHODS: Human medulloblastoma cell lines, Daoy and D341, were used in this study, and the miR-497 expression in the cells was measured by Quantitative PCR with fluorescence. The Daoy cells were divided into the mimics group (Daoy cells treated with mimics), inhibitor group (Daoy cells treated with inhibitor), normal Daoy cells, ARHGDIA siRNA group (Daoy cells transfected with ARHGDIA siRNA), ARHGDIA control group (Daoy cells did not receive any treatment), and negative control group (normal cells transfected with ARHGDIA siRNA). The expression of miR-497 and ARHGDIA mRNA was measured by Quantitative PCR with fluorescence, while the level of ARHGDIA protein was measured by Western blot. The binding capability of ARHGDIA and miR-497 was assessed by luciferase assay, the migration of cells was assessed by wound healing assay, and the invasion of cells was assessed by Transwell assay. RESULTS: Compared to D341 cells, the miR-497 level was significantly higher in the Daoy cells (P < 0.01). The dual-luciferase reporter assay showed that miR-497 targets ARHGDIA. Transfecting the normal Daoy cells with miR-497 mimics significantly reduced the expression of ARHGDIA protein (P < 0.05), while transfecting normal Daoy cells with miR-497 inhibitor significantly increased the expression of ARHGDIA protein (P < 0.05). Consequently, the migration and invasion capability of cells increased significantly after transfection with miR-497 mimic (P < 0.05), and decreased significantly after transfection with miR-497 inhibitor (P < 0.05). In addition, the migration and invasion capabilities of the cells also increased significantly after transfection with ARHGDIA siRNA (P < 0.05). CONCLUSIONS: miR-497/ARHGDIA axis participates in the in vitro migration and invasion of human medulloblastoma cell lines.

Measurement-device-independent quantum key distribution via quantum blockade.

Efficiency in measurement-device-independent quantum key distribution(MDI-QKD) can be improved not only by the protocol, but also single-photon sources. We study the behavior of MDI-QKD with statistical fluctuation using quantum blockade source. Numerical simulation for a type of 4-intensity protocol shows that, after parameter optimization, this source can improve the final key rate by 100 times compared with traditional weak coherent state sources.

Measurement-Device-Independent Quantum Key Distribution Over a 404 km Optical Fiber.

Measurement-device-independent quantum key distribution (MDIQKD) with the decoy-state method negates security threats of both the imperfect single-photon source and detection losses. Lengthening the distance and improving the key rate of quantum key distribution (QKD) are vital issues in practical applications of QKD. Herein, we report the results of MDIQKD over 404 km of ultralow-loss optical fiber and 311 km of a standard optical fiber while employing an optimized four-intensity decoy-state method. This record-breaking implementation of the MDIQKD method not only provides a new distance record for both MDIQKD and all types of QKD systems but also, more significantly, achieves a distance that the traditional Bennett-Brassard 1984 QKD would not be able to achieve with the same detection devices even with ideal single-photon sources. This work represents a significant step toward proving and developing feasible long-distance QKD.