Objective:To investigate the inhibitory effect of calcium hydroxide on methicillin-resistant Staphylococcus aureus and the related inhibition mechanism.Methods:To determine the minimum inhibitory concentration of calc...Objective:To investigate the inhibitory effect of calcium hydroxide on methicillin-resistant Staphylococcus aureus and the related inhibition mechanism.Methods:To determine the minimum inhibitory concentration of calcium hydroxide using microplate dilution method;to compare the effects of calcium hydroxide at 8MIC,MIC,1/4MIC and 0 concentrations on MRSA using growth curve method;to determine the effects of calcium hydroxide on the cell membrane of methicillin-resistant Staphylococcus aureus using calcium xanthophyll and propidium iodide fluorescence staining The effect of calcium hydroxide on the morphology of methicillin-resistant Staphylococcus aureus was observed by scanning electron microscopy;the inhibition mechanism of calcium hydroxide on MRSA was investigated by sodium dodecyl sulfate polyacrylamide gel electrophoresis of protein bands.Results:The MIC of calcium hydroxide on MRSA was 3.125 mg/mL;the fluorescence intensity showed significant changes after co-culture of calcium hydroxide with bacteria;MRSA appeared to be significantly crumpled and broken in the presence of calcium hydroxide;the SDS-PAGE experimental bands indicated that the protein inside the bacteria decreased accordingly with the increase of calcium hydroxide concentration.Conclusion:Calcium hydroxide has a significant inhibitory effect on the growth of MRSA,and its bactericidal mechanism may be related to the destruction of bacterial body structure.展开更多
Objective:To prepare a bone repair material with certain mechanical strength and biological activity,this paper used calcium sulfate hemihydrate(CSH)powder compounded with calcium hydroxide(Ca(OH)2)powder to prepare a...Objective:To prepare a bone repair material with certain mechanical strength and biological activity,this paper used calcium sulfate hemihydrate(CSH)powder compounded with calcium hydroxide(Ca(OH)2)powder to prepare a bone repair scaffold material for physicochemical property characterization and testing.Methods:The physical and chemical properties and characterization of the dried and cured bone repair materials were determined by Fourier infrared spectroscopy(FT-IR),X-ray diffraction(XRD),and scanning electron microscopy;Universal material testing machine to determine the mechanical and mechanical strength of composite materials.Results:XRD showed that the structure of the composite material phase at 5%concentration was calcium sulfate hemihydrate and calcium hydroxide after hydration.The FT-IR and XRD analyses were consistent.Scanning electron microscopy(SEM)results showed that calcium hydroxide was uniformly dispersed in the hemihydrate calcium sulfate material.0%,1%,5%,and 10%specimen groups had compressive strengths of 3.86±3.1,5.27±1.28,8.22±0.96,and 14.4±3.28 MPa.10%addition of calcium hydroxide significantly improved the mechanical strength of the composites,but also reduced the the porosity of the material.Conclusion:With the addition of calcium hydroxide,the CSH-Ca(OH)2 composite was improved in terms of mechanical material and is expected to be a new type of bone repair material.展开更多
基金National Natural Science Foundation of China(No.82060347)。
文摘Objective:To investigate the inhibitory effect of calcium hydroxide on methicillin-resistant Staphylococcus aureus and the related inhibition mechanism.Methods:To determine the minimum inhibitory concentration of calcium hydroxide using microplate dilution method;to compare the effects of calcium hydroxide at 8MIC,MIC,1/4MIC and 0 concentrations on MRSA using growth curve method;to determine the effects of calcium hydroxide on the cell membrane of methicillin-resistant Staphylococcus aureus using calcium xanthophyll and propidium iodide fluorescence staining The effect of calcium hydroxide on the morphology of methicillin-resistant Staphylococcus aureus was observed by scanning electron microscopy;the inhibition mechanism of calcium hydroxide on MRSA was investigated by sodium dodecyl sulfate polyacrylamide gel electrophoresis of protein bands.Results:The MIC of calcium hydroxide on MRSA was 3.125 mg/mL;the fluorescence intensity showed significant changes after co-culture of calcium hydroxide with bacteria;MRSA appeared to be significantly crumpled and broken in the presence of calcium hydroxide;the SDS-PAGE experimental bands indicated that the protein inside the bacteria decreased accordingly with the increase of calcium hydroxide concentration.Conclusion:Calcium hydroxide has a significant inhibitory effect on the growth of MRSA,and its bactericidal mechanism may be related to the destruction of bacterial body structure.
基金National Natural Science Foundation of China(No.82060347)Postgraduate innovation research project of Hainan Medical College(No.HYYS2020-38)。
文摘Objective:To prepare a bone repair material with certain mechanical strength and biological activity,this paper used calcium sulfate hemihydrate(CSH)powder compounded with calcium hydroxide(Ca(OH)2)powder to prepare a bone repair scaffold material for physicochemical property characterization and testing.Methods:The physical and chemical properties and characterization of the dried and cured bone repair materials were determined by Fourier infrared spectroscopy(FT-IR),X-ray diffraction(XRD),and scanning electron microscopy;Universal material testing machine to determine the mechanical and mechanical strength of composite materials.Results:XRD showed that the structure of the composite material phase at 5%concentration was calcium sulfate hemihydrate and calcium hydroxide after hydration.The FT-IR and XRD analyses were consistent.Scanning electron microscopy(SEM)results showed that calcium hydroxide was uniformly dispersed in the hemihydrate calcium sulfate material.0%,1%,5%,and 10%specimen groups had compressive strengths of 3.86±3.1,5.27±1.28,8.22±0.96,and 14.4±3.28 MPa.10%addition of calcium hydroxide significantly improved the mechanical strength of the composites,but also reduced the the porosity of the material.Conclusion:With the addition of calcium hydroxide,the CSH-Ca(OH)2 composite was improved in terms of mechanical material and is expected to be a new type of bone repair material.