Applications of MOFs as Luminescent Sensors for Environmental Pollutants.

The environmental pollution has become a serious issue because the pollutants can cause permanent damage to the DNA, nervous system, and circulating system, resulting in various incurable diseases, such as organ failure, malformation, angiocardiopathy, and cancer. The effective detection of environmental pollutants is urgently needed to keep them far away from daily life. Among the reported pollutant sensors, luminescent metal-organic frameworks (LMOFs) with tunable structures have attracted remarkable attention to detect the pollutants because of their excellent selectivity, sensitivity, and recyclability. Although lots of metal-organic framework (MOF)-based luminescent sensors have been summarized and discussed in previous reviews, the detection of environmental pollutants, especially radioactive ions and heavy metal ions, still have not been systematically presented. Here, the sensing mechanisms and construction principles of luminescent MOFs are discussed, and the state-of-the-art MOF-based luminescent sensors of environmental pollutants, including pesticides, antibiotics, explosives, VOCs, toxic gas, toxic small molecules, radioactive ions, and heavy metal ions are highlighted. This comprehensive review may further guide the development of luminescent MOFs and promote their practical applications for sensing environmental pollutants.

Effect of the Wnt signal-RANKL/OPG axis on the enhanced osteogenic integration of a lithium incorporated surface.

Bone remolding involves the formation of new bone by osteoblasts and the absorption of old bones by osteoclasts. Due to the vital role of osteoblasts and osteoclasts during bone regeneration, it might be feasible to promote osseointegration around the titanium implants by stimulating osteoblasts and inhibiting osteoclasts by modifying the surfaces of the implants. Lithium is used in the treatment of psychiatric patients, and it may be associated with osteogenesis. In this study, lithium was incorporated with sandblasted, large-grit and acid-etched titanium implants via a hydrothermal treatment. In vitro, the nano-scale surface enhanced the adhesion and proliferation of bone marrow mesenchymal stem cells (BMSCs). Moreover, the SLA-Li surface displayed a negative effect on the process of osteoclastogenesis. Further mechanism analysis indicated that the canonical Wnt/ß-catenin signaling pathway was activated according to the results of RT-PCR and western blotting. More importantly, the RANKL/OPG signaling axis was also involved in these effects on the SLA-Li surface. The experiments in vivo proved that the SLA-Li surface could induce the bone formation and osseointegration during the early osseointegration after the dental implant surgery. These results suggested that bone homeostasis could be manipulated by an SLA-Li surface, which implied that this new surface might serve as a promising material for clinical application in the future.

Long-term outcomes of osteotome sinus floor elevation without bone grafts: a clinical retrospective study of 4-9 years.

OBJECTIVE: To evaluate the long-term clinical and radiographic outcomes of dental implant placed using osteotome sinus floor elevation (OSFE) without bone grafts, and to analyze the potential influence factors of implant survival and endo-sinus bone remodeling. MATERIAL AND METHODS: A retrospective study design was adopted. The clinical and radiographic data of 96 implants in 80 patients were collected after 4-9 (mean 5.40) years follow-up. Implant failures, peri-implant marginal bone loss (MBL), and endo-sinus bone remodeling on the radiographs were evaluated. A life-table analysis was used to assess the implant survival. Statistical models were established to investigate the potential influence factors of implant survival and endo-sinus bone gain (ESBG). RESULTS: In total, nine implants in seven patients failed, giving the 9-year cumulative survival rates of 90.6% and 91.3% for implant-based analysis and patient-based analysis, respectively. The mean MBL between implant installation and the 4- and 9-year follow-up visit was 0.46 ± 0.88 and 0.50 ± 1.69 mm, respectively. The average ESBG on radiographs was 2.95 ± 1.25 and 2.16 ± 1.13 mm at the 4- and 9-year follow-up. The final ESBG was found to be positively correlated to implant protrusion length after surgery without any other factors related. The implant survival rate was significantly lower in severe atrophic site (residual bone height <5 mm). CONCLUSION: Osteotome sinus floor elevation without bone grafts is a predictable treatment modality in the long run. But it should be used with caution when the initial bone height of the edentulous site is lower than 5 mm. The final endo-sinus bone height was found to be positively correlated to implant protrusion length measured on radiographs immediately after implant installation.

Osteoblast responses to thin nanohydroxyapatite coated on roughened titanium surfaces deposited by an electrochemical process.

PURPOSE: The purpose of this study was to investigate in vitro osteoblast responses to the thin nano-hydroxyapatite (HA) coating on porous implant surfaces. MATERIALS AND METHODS: Surface characteristics of nano-HA coating were evaluated by x-ray diffractometer (XRD) and Fourier transform infrared spectroscopy (FTIR). Murine preosteoblast cell (MC3T3-E1) proliferation, alkaline phosphatase (ALP) activity, and osteocalcin release on nano-HA coated surfaces were compared with HA-coated surfaces. RESULTS: The XRD pattern demonstrated that the peak of nano-HA coating matched well with the standard HA patterns. FTIR spectra also showed that the coating consisted of pure HA crystals. Significant increases in cell proliferation, total protein on day 7, ALP activity on day 14 and day 21, and osteocalcin production on day 21 (P < .05) were observed for nano-HA coated surfaces. CONCLUSIONS: It was concluded that thin nano-HA coating, deposited by the electrochemical process, improved proliferation and differentiation of osteoblasts.

Osteoblast response to porous titanium surfaces coated with zinc-substituted hydroxyapatite.

BACKGROUND: The aims of this study were to deposit a zinc-hydroxyapatite (Zn-HA) coating on titanium surfaces by using the electrochemical process and investigate the cell response to the Zn-HA-coated titanium surface. STUDY DESIGN: Surface characteristics were evaluated by scanning electron microscopy (SEM) and inductively coupled plasma atomic emission spectroscopy (ICP-AES). Murine preosteoblast cell (MC3T3-E1) proliferation, alkaline phosphatase (ALP) activity, and osteocalcin release on Zn-HA-coated surfaces were compared with HA-coated surfaces. RESULTS: Field-emission SEM observation showed rod-like HA crystals with a hexagonal cross-section on the HA-coated surface, although the hexagon of the cross-section of Zn-HA crystals became irregular. ICP-AES analysis showed that Zn was present in the Zn-HA coatings at a Zn/(Ca+Zn) molar ratio of 1.04%. Significant increases in cell proliferation, ALP activity on day 7, and osteocalcin production on day 14 (P < .05) were observed for Zn(2+)-containing HA-coated surfaces. CONCLUSIONS: The present study showed that a Zn-HA coating deposited by using the electrochemical process enhances proliferation and differentiation of osteoblasts, which has the potential benefit to enhance implant osseointegration.

Simvastatin-loaded porous implant surfaces stimulate preosteoblasts differentiation: an in vitro study.

OBJECTIVE: Recent studies demonstrate that simvastatin stimulates bone formation, suggesting the potential application in dental implantology. In this study, our lab developed a simvastatin-loaded titanium porous surface. The aim was to investigate the effect of simvastatin-loaded titanium surfaces on the promotion of osteogenesis in preosteoblasts (MC3T3-E1) in vitro. STUDY DESIGN: The control group consisted of cells cultured on titanium disks without any intervention for different time intervals (4, 7, and 14 days), and the experimental groups (simvastatin-loaded groups) consisted of cells cultured on titanium disks that were preincubated in varying concentration (10(-7) mol/L, 10(-6) mol/L, 10(-5) mol/L, and 10(-4) mol/L) of simvastatin for the same time intervals of the control group. Alkaline phosphatase (ALP) activity, type I collagen synthesis, and osteocalcin release were used to measure the cellular osteoblastic activities. RESULTS: All simvastatin-loaded groups showed increased ALP activity compared with the control group at every time point, especially the 10(-7) mol/L group, which significantly increased the activity almost fourfold at 4 days (P < .05). In the type I collagen synthesis assay, all simvastatin-loaded groups showed an increase, and the effect was inverse dose dependent (maximal at 10(-7) mol/L). This stimulatory effect of simvastatin was also observed in the osteocalcin release assay (P < .05; at 10(-7) mol/L, 10(-6) mol/L, maximal at 10(-7) mol/L). CONCLUSION: These results indicate that simvastatin-loaded porous implant surfaces promote accelerated osteogenic differentiation of preosteoblasts, which have the potential to improve the nature of osseointegration.

Biomechanical comparison of biomimetically and electrochemically deposited hydroxyapatite-coated porous titanium implants.

PURPOSE: The purpose of this study was to investigate the effects of biomimetically and electrochemically deposited hydroxyapatite on the fixation of an implant with bone tissue. MATERIALS AND METHODS: Implants were separated into 3 groups: roughened group, biomimetically deposited calcium-phosphorus (BDCaP) group, and electrochemically deposited hydroxyapatite (EDHA) group. We randomly inserted 90 implants into the femurs of 45 rabbits. After 2, 4, and 8 weeks, the femurs were retrieved and prepared for removal torque tests (RTQs) and field-emission scanning electron microscopy observation. RESULTS: During the test period, the EDHA group showed significantly greater RTQ values than did the roughened group and BDCaP group. The BDCaP group failed to increase the RTQ values compared with the roughened group. Field-emission scanning electron microscopy observation showed that the amount of attached bone tissue on the EDHA-coated implant surface was more than that on the roughened and BDCaP-coated implant surfaces during the test period. CONCLUSION: The electrochemical hydroxyapatite coating contributes to the fixation between bone and implant compared with the roughened surface, whereas the biomimetic calcium-phosphorus coating has little effect on the fixation.

Effects of biomimetically and electrochemically deposited nano-hydroxyapatite coatings on osseointegration of porous titanium implants.

OBJECTIVE: The objective of this study was to evaluate and compare the effects of biomimetically and electrochemically deposited nano-hydroxyapatite (HA) coatings on the osseointegration of porous titanium implants after 6 and 12 weeks of insertion in a rabbit bone model. STUDY DESIGN: Forty-two roughened implants were separated into 3 groups: roughened group, biomimetically deposited CaP (BDCaP) group, and electrochemically deposited HA (EDHA) group. Implant surface morphology of 3 groups (n = 6) was performed by field-emission scanning electron microscope (FSEM). Thirty-six implants were randomly inserted into tibias of 18 rabbits. After 6 and 12 weeks, tibias were retrieved and prepared for histomorphometric evaluation. RESULTS: FSEM showed the BDCaP crystals were flakelike, whereas the EDHA crystals were rodlike with a hexagonal cross section. Histological observation showed bone growth along the surfaces after 6 weeks. New bones were also seen on the BDCaP and EDHA implant surfaces in the marrow space. New bone on the roughened and EDHA implants became mature after 12 weeks. The EDHA implant showed significantly greater BIC and bone area compared with the roughened and BDCaP implants during 6 to 12 weeks (P < .05). The BDCaP implants did not evidently increase BIC and bone area compared to the roughened implants during the test period (P > .05). CONCLUSION: These results suggest that the EDHA coating has a better bone integration potential than does the BDCaP coating.

Bone responses to titanium implants surface-roughened by sandblasted and double etched treatments in a rabbit model.

OBJECTIVE: The objective of this study was to investigate bone responses to titanium implants surface-roughened by sandblasted and double-etched treatments in a rabbit model. STUDY DESIGN: Sixty implants of 10 mm in length (30 machined and 30 roughened) were inserted into femurs of 30 rabbits and 30 implants of 8 mm in length (15 machined and 15 roughened) were inserted into tibias of 15 rabbits. At 2, 4, and 8 weeks postimplantation, femurs and tibias were retrieved and prepared for removal torque tests (RTQ) and histomorphometric evaluation, respectively. RESULTS: The roughened implants showed 66.21%, 89.06%, and 115.00% greater RTQ values than did the machined implants at 2, 4, and 8 weeks. Histomorphometric evaluation demonstrated the roughened implants significantly increased bone-implant contact and peri-implant bone formation during all observation periods. CONCLUSION: These results suggest this surface-roughened approach provides the implant surface with a considerable osteoconductive potential promoting a high level of bone integration with bone.

Effect of H2O2/HCl heat treatment of implants on in vivo peri-implant bone formation.

PURPOSE: To investigate the effect of H2O/HCl heat treatment on peri-implant bone formation in vivo. MATERIALS AND METHODS: Twenty Ti-6Al-4V implants and 30 Ti-6Al-4V discs were used in this study. The implants and discs were separated into 2 groups: sandblasted and dual acid-etched group (control group) and sandblasted, dual acid-etched and H2O2/HCl heat-treated group (test group). Surface morphology, roughness, and crystal structure of the discs were analyzed by field-emission scanning electron microscopy, atomic force microscopy, and low angle X-ray diffractometry. The implants were inserted into the femurs of 10 adult white rabbits. Animals were injected with fluorescent bone labels at 1, 5, and 7 weeks following surgery to monitor progress of bone formation. Animals were euthanized 8 weeks postsurgery, and block biopsies were prepared for histologic and histometric analysis. RESULTS: Microscopic evaluation showed the surfaces were quite irregular for both techniques; however, the test surface demonstrated consistently smaller surface irregularities. The differences in Sa values were significant (P = .022). No significant differences were found in the maximum peak-to-valley ratio values (P = .258). X-ray diffractometry analysis showed that titanium dioxide was found on the test surface. New bone was formed on both implant surfaces. The bone-implant contact pattern appeared to produce a broad-based direct contact. Test implants demonstrated 7.13% more bone to implant contact (P = .003) and 15.42% more bone to implant contact for 3 consecutive threads (P = .001) than control implants. Test implants demonstrated 37.04% more bone area 500 microm outside of implant threads (P = .004) and 51.97% more bone area within 3 consecutive threads (P = .001) than control implants. No significant differences were found in bone area within all implant threads between the two groups (P = .069). CONCLUSION: This study demonstrated that implants heat-treated with H2O2/HCl solution enhanced peri-implant bone formation.