Study of celluar toxicity and antibacterial property of nano-silver coating modified denture base / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate celluar toxicity and antibacterial property of nano-silver coating modified denture base and to provide a theortical basis for clinical application.</p><p><b>METHOD</b>The samples were divided into coating group and denture base group. Samples in coating groups were treated with silver ion sputtering and were further divided into the 10, 20, 40, 60, 80, 100 s subgroups according to their sputtering time. Surface microstructure of samples in coating groups and denture base group were observed by scanning electron microscopy (SEM), and composition of material surface were determined with energy dispersive spectrum (EDS) analysis. Methyl thiazolyl terazolium (MTT) method was used to analysis L929 cells proliferation rate and cell toxicity grade while the coating groups (n = 6) and group test specimens (n = 6), negative control (polyethylene, PE) (n = 6) and positive control group (PVC-org.Sn) (n = 6) were co-cultured with L929 cells. The antibacterial properties of coating groups were investigated by using the bacterial membrane adhering method with Streptococcus mutans and Candida albicans.</p><p><b>RESULTS</b>SEM observation showed that the surface of control group specimens were smooth, whereas dense and uniform distributed nano silver particles were visible on the surface of coating group specimens. The silver particles were round, and the diameter size was 10 nm. MTT assay showed that after being co-cultured with specimens in control group, L929 cell had higher proliferation rate than 100% at 24, 48, 72 h, and cytotoxicity were graded 0. The membrane adhering method results showed that all of bacterial colonies were found in control group, but without anything at the coating groups.</p><p><b>CONCLUSIONS</b>Deposition of nano silver on the denture base surface by ion sputtering method is a viable method. There's no cytotoxicity of series Ag-coating material. Nano-silver modified denture base material benefits L929 cell surface proliferation and has antibacterial action.</p>

Micromorphological observation of bacterial biofilms on ciliated epithelia of chronic rhinosinusitis / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To observe the micromorphological characteristic of bacterial biofilm on mucosa of chronic rhinosinusitis (CRS).@*METHOD@#Mucosa samples of middle turbinate were obtained from 4 patients of CRS during ESS. The size of each sample was about 4 mm x 4 mm. The samples were fixed in 4% paraformaldehyde for 24 hours, then fixed in 1% osmium tetroxide for 2 hours, graded dehydration with ethanol, dried with carbon dioxide and sputter coated with gold. The ultrastructure of these samples was observed by scanning electron microscope.@*RESULT@#Bacterial biofilms were found on samples in all 4 patients. The biofilms were mainly formed on the surface of cilia. The bacterial flagella and cilia were intertwined. The biofilms could be found in a lot kinds of bacterial infections or mixed infections which were caused by multiple bacteria and fungi.@*CONCLUSION@#Bacterial biofilm could be formed on ciliated epithelia.

Preparation of porous nano-hydroxyapatite/collagen composite and its capability / 吉林大学学报(医学版)

Objective To study the simple preparation method and structure of nano-hydroxyapatite/collagen composite, to investigate new substitute of repairing bone for using in tissue engineering. Methods Porous nano-hydroxyapatite was made of Ca (OH)2 and H3PO4. Collagen was drawn from fresh adult bovine tendon. The two materials were prepared into biomembrane through the glutaraldehyde and freeze-drying. The crystallite phase, micro-morphology, structure, crystallite size of the composite were examined by XRD and scanning electronic microscop (SEM). Results The results showed that the composite structure was porous and consisted of nano-hydroxyapatite (10 nm ? 50 nm - 20 nm ? 80 nm) and collagen fiber. The crystallite phases and size of the composite was similar to that of natural bone. Conclusion The porous nano-hydroxyapatite /collagen composite is expected to be an ideal substitute of repairing bone.