Antibacterial performance of cerium oxide nanoenzyme against Escherichia coli / 中国组织工程研究

BACKGROUND:The increase in multi-drug resistant bacterial infections has become a major problem in modern healthcare due to the development of bacterial resistance to antibiotics and the development of new antibacterial alternative drug materials is of great importance. OBJECTIVE:To synthesize and perform a series of characterization of a CeO2 nanoenzyme to investigate its biocompatibility and antibacterial properties against Escherichia coli. METHODS:CeO2 nanoenzymes were synthesized using a hydrothermal method.The morphology,product composition,and chemical composition were analyzed using characterization methods such as X-ray diffraction,X-ray photoelectron spectroscopy,Fourier infrared analysis,Raman spectroscopy,scanning electron microscopy,and transmission electron microscopy.The peroxide-mimetic enzyme activity of CeO2 nanoenzymes was characterized using TMB color development assay.The toxic effect of CeO2 nanoenzymes at different concentrations(10,25,and 50 μg/mL)on mouse fibroblast L929 cells was evaluated using the CCK-8 assay.The antibacterial properties of CeO2 nanoenzymes against Escherichia coli under different conditions were evaluated using the plate coating method.Changes in intra-bacterial reactive oxygen species after treatment with different conditions were detected using a reactive oxygen species detection kit. RESULTS AND CONCLUSION:(1)The morphology of the synthesized CeO2 nanoparticles was rod-shaped,with Ce3+ accounting for 29.87%of the total Ce3+/Ce4+ and an average grain size of 7.4 nm.In a slightly acidic environment containing TMB and pH=5.5,CeO2 nanoenzymes mixed with H2O2 showed excellent peroxidase activity,but did not show peroxidase simulated activity at pH=7.4.(2)There was no statistically significant difference in the toxic effects of CeO2 nanoparticles at various mass concentrations on mouse fibroblast L929 cells.(3)In a slightly acidic environment at pH 5.5,Escherichia coli was inhibited to a certain extent in the presence of CeO2 nanoenzyme alone at a concentration of 10 μg/mL,with a decrease in CFU results of about 0.5 log(P＜0.01);in a slightly acidic environment containing 50 μmol/L H2O2,CeO2 nanoenzyme showed excellent antibacterial effects against Escherichia coli,with a decrease in Escherichia coli CFU results of by about 1.5 log(P＜0.001).After CeO2 nanoenzymes interacted with Escherichia coli,the level of reactive oxygen species in Escherichia coli increased(P＜0.05);after CeO2 nanoenzymes interacted with Escherichia coli together with H2O2,the level of reactive oxygen species in Escherichia coli increased significantly(P＜0.001).(4)The results show that the CeO2 nanoenzymes have good biocompatibility,are inherently antibacterial,and can exhibit peroxidase activity in a slightly acidic environment containing low concentrations of H2O2,and generate reactive oxygen species to kill bacteria,thus showing excellent antibacterial effects.

Applications of 3D printing in periodontal tissue engineering / 中国组织工程研究

BACKGROUND:Three-dimensional(3D)printing is an emerging technology in the field of dentistry.It utilizes a layer-by-layer manufacturing technique to create scaffolds suitable for periodontal tissue engineering applications.Tissue scaffolds produced through 3D printing can possess controlled characteristics,including internal structure,porosity,and interconnectivity,making it an ideal strategy for periodontal tissue engineering. OBJECTIVE:To review the applications of 3D printed scaffolds in periodontal regeneration. METHODS:English search terms were"3D printing,periodontal tissue engineering,additive manufacturing,regenerative medicine,bioengineering,scaffold,bioprinting,periodontitis".Chinese search terms were"3D printing,additive manufacturing,periodontal tissue engineering,scaffolds,bio-inks,bioprinting,tissue engineering".Relevant literature published from 2000 to 2023 in PubMed and CNKI databases was retrieved and included in the review. RESULTS AND CONCLUSION:Over the past few decades,3D printing technology has made significant progress and breakthroughs in tissue engineering and biomedical fields.3D printing technology can provide highly personalized treatment programs,improve the suitability and therapeutic effect of therapeutic stents,and has broad application prospects in periodontal tissue engineering.In periodontal tissue engineering,3D printing applications can better mimic the complex structures of biological tissues and manufacture biocompatible scaffold materials with suitable mechanical and rheological properties.The layer-by-layer construction of tissue engineering scaffolds through 3D printing not only enables the creation of precise and intricate scaffold models for personalized treatment of periodontal disease but also facilitates the incorporation of complex microstructures and channels within the scaffolds to promote cell growth and tissue regeneration.

Latest research on zirconia implant surface treatment / 中国组织工程研究

BACKGROUND: Recently, zirconia ceramic implants have been reported to be used in clinic. Increasing studies on surface treatment of ziconia implants have been done, in order to promote bone-implant osseointegration and increase the success rate of implantation. There are no recognized surface treatment techniques of zirconia implants as yet.OBJECTIVE: To summarize the research progress in surface treatment techniques of zirconia implants.METHODS: The first author searched the CNKI, PubMed and Web of Science databases for relevant articles published from January 2000 to October 2016. The keywords were zirconia or zirconium, implant, surface treatment in Chinese and English, respectively. The search condition was((zirconia or zirconium) AND implant) AND surface treatment. Here,we reviewed the surface treatment techniques of zirconia implants, and introduced the properties, the surface treatment techniques and commercialization of zirconia implants.RESULTS AND CONCLUSION: Totally 23 papers were included in result analysis. Commonly used surface treatment technologies of zirconia implants include sand blasting, acid etching, sandblast and acid-etching, selective filtration etching, laser, ultraviolet and coating. These technologies all contribute to improving the surface activity of the implant,increasing the roughness, and promoting bone bonding to a certain extent.Because of the very limited experiments,further investigations are required to explore the optimum technique for the surface treatment of zirconia implants.

Research progress of Hedgehog signaling pathway regulating RANKL expression in osteoblasts / 中国组织工程研究

BACKGROUND: Hedgehog signaling pathway is shown to contribute to the osteogenesis of bone marrow mesenchymal stem cells, and to play an important role in regulating the expression of RANKL in osteoblasts. Nowadays, the definite signal transduction pathway has been revealed gradually.OBJECTIVE: To review the research progress of RANKL in osteoblasts that regulated by hedgehog signaling pathway.METHODS: A computer-based online search in CNKI, Google Scholar and PubMed databases was performed with the key words of Hedgehog, osteoblast, BMSCs, PTHrP, CREB, NFAT, RANKL in English and Chinese, respectively.Literatures related to the expression of RANKL in osteoblasts that regulated by the Hedgehog signaling pathway were included initially and 37 eligible articles were extensively summarized for review.RESULTS AND CONCLUSION: The Hedgehog signaling pathway plays an advanced role in the osteogenic differentiation of bone marrow mesenchymal stem cells, and also upregulates intracellular parathyroid hormone related protein, which activates its downstream signaling molecules cAMP response element binding protein and nuclear factor of activated T cells ulteriorly, to promote the expression of RANKL in osteoblasts and increase the differentiation and formation from osteoclast precursor cells to mature osteoclasts.

Preliminary application of injectable calcium phosphate cement/poly (lactic-co-glycolic acid) microspheres for extraction site preservation / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the feasibility of extraction site preservation using injectable calcium phosphate cement (CPC) combine with poly (lactic-co-glycolic acid) (PLGA) microspheres.</p><p><b>METHODS</b>Immediate extraction defects models were created in canine mandibles, and the defects were filled with CPC/PLGA (experimental group, E) , Bio-Oss (positive control, P), non-treatment (blank control, B) respectively. Dogs were sacrificed after 4, 8, 12 weeks post operation. Statistical analysis were conducted using SPSS 19.</p><p><b>RESULTS RESULTS</b>of radiological observation showed that there were not significantly different between groups in 4 and 8 week (P > 0.05). After 12 week,E (114.9 ± 8.4) were not significantly different compared with P (117.4 ± 12.1) (P > 0.05) , both were significantly higher than B (95.0 ± 12.6) (P < 0.05) . Histology examination showed that at 4 week following surgery, the result of newly formed bone was as follow, P[ (87.5 ± 1.5) %] > B[(78.7 ± 2.7)%] > E[(69.2 ± 1.8)%] (P < 0.05). At 8, 12 week, results of P[(94.0 ± 2.3)% and (93.5 ± 1.9) %] and E[ (94.7 ± 1.1) % and (96.0 ± 0.9) %] were better than those of B[ (76.8 ± 3.0)% and (87.0 ± 2.4)%] (P < 0.05).</p><p><b>CONCLUSIONS</b>The effect of CPC/PLGA repair immediate alveolar ridge defects is the same as that of Bio-Oss, and CPC/PLGA can be used as a material in extraction site preservation.</p>

Prevalence and risk factors of human papillomavirus infectious in HIV-positive women / 中华临床感染病杂志

Objective To evaluate the prevalence and risk factors of human papillomaviruses (HPV)infection among human immunodeficiency virus(HIV)-positive women.Methods Totally 178HIV-positive and 122 HIV-negative women were enrolled.Structured interviews,peripheral CD4 + T cells counts and cervical specimens were obtained.Polymerase chain reaction(PCR)assay was used to identify HPV types. SPSS 16.0 was used for statistical analysis,and logistic regression was used to identify independent prognostic factors for high-risk HPV infection. Results HPV positive rate,high-risk and multiple HPV infection rates were 38.2% vs.12.3% ,35.4% vs.8.2% ,and 13.5% vs.3.3% in HIVpositive women and HIV-negative women,respectively,and the differences were of statistical significance (x2 =24.77,29.08 and 8.91,P ＜0.05).The common types of high-risk HPV were similar between HIV-positive and HIV-negative women(HPV16,52,58 and 18).CD4 + T count ＜ 350/pL,HIV-positive in husband,and HIV infection through sexual contact were risk factors for high-risk HPV infection in HIV-positive women.Conclusion sThe prevalence of HPV infection in HIV-infected women is high,especially for high-risk HPV infection and multiple infection.High-risk HPV infection usually occurs in HIV-positive women with low immune status,HIV infection through sexual contact and HIV-positive husband.

Study on bonding strength of TF adhesive compounded with nanograde hydroxyapatite / 生物医学工程学杂志

TF no-mix orthodontic adhesive was compounded in different weight proportion of nanograde hydroxyapatite as 10%, 20% and 30%, for use in this comparative study on composites. 80 orthodontic brackets were cemented and divided into 8 experimental groups, and TF adhesive was set as the control group. The tensile strength and shear strength were tested respectively. The results showed that the group of 10% nanograde hydroxyapatite obtained the greatest bonding strength (9.668 +/- 1.0649 MPa in tensile strength and 11.991 +/- 1.4135 MPa in shear strength), and there was significant difference between the 10% group and the other groups (P < 0.05, one-way ANAOV). It is concluded that the bonding strength can be enhanced when TF adhesive is compounded in suitable proportion of nanograde hydroxyapatitie.