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Objective To evaluate the feasibility, efficacy and safety of new nano material occluder of single rivet type (left-disk with no-hub) in treating ventricular septal defect (VSD) in order to provide experimental basis for clinical application. Methods A total of 26 healthy adult dogs were selected for this study . Under thoracotomy , VSD model was established through fluoroscopically-guided percutaneous puncturing of the right ventricular free wall. The models were randomly and equally divided into the study group(n=13, using nano material VSD occluder) and the control group(n=13, using double-hub nitinol occluder). Every two dogs from each group were sacrificed each time at one, 2, and 3 months after percutaneous closure of VSD with corresponding occluder, the tissue samples were collected and sent for gross examination as well as for the optical and electronic microscopy study;the blood concentration of nickel ion was also determined. The state of endothelialization after implantation of the new type occluder was evaluated, and the complications such as residual shunt and superficial thrombus formation were recorded. The results were analyzed. Results By open chest operation with small incision and percutaneous puncturing of the right ventricular free wall, VSD model was successfully established in all 26 dogs. The success rate of the implantation of the VSD occluder in the study group was 100%, while it was 91.7% in the control group. One, 2, 3 and 6 months after the implantation, the heart specimens of 25 dogs were removed and gross examination showed that neither occluder displacement nor alloy wire fracture occurred in both groups. No thrombus formation or vegetation attached on the disk surface was observed. One month after the procedure , in the study group the bilateral disk surfaces of the occluder were covered with thin layer transparent tissue , which were proved to be composed of the fibrous tissue and endothelial cells through pathologic and electronic microscopy study. Six months after implantation, the superficial tissue of the occluder became further thickened and the occluder edge became fused with the surrounding heart tissue. Conclusion The design of the new VSD nano materials occluder, which has a left-disk with no hub, is very scientific. Compared with double-hub nitinol occluder, the new device can shorten the time of complete endothelialization and effectively occlude the VSD. Therefore, this new nano material occluder has promising prospect in clinical application.
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Rapid detection of pathogenic microorganisms is important to the prevention and control of diseases.Com-pared with traditional approaches, electrochemical DNA biosensors present great advantages in promising rapid, portable, sensitive and cost-saving detection of pathogens.In this review, the working principle of electrochemical DNA biosensors and the progress in detection of pathogens is introduced, the latest developments of DNA tetrahedron structure and new nano materials in electrochemical DNA biosensors are reviewed, and the challenges to and prospects of development in this field are also discussed.
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As a novel functional material with great application values, magnetic nanobead has been in fast development in recent years. Magnetic nanobead is provided with characteristics of beth polymeric and mag-netic particles, so it can be detected easily fi'om the medium and can be easily located since they can move di-rectionally when motivated by external electric field. The magnetic nanobead is widely used in biomedical engi-neering research due to its unique physical and chemical properties which simplify the complex experiments op-erations and shorten the testing period.
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Objective To study the feasibility of applying nanometer ceramics artificial bone in clinical repair of bone defects. Methods The animal models of bone defect was made on the unilateral radius of 45 New Zealand white rabbits, which were divided into experimental group(repair with nanometer ceramics artificial bone), control group (repair with ceramics artificial bone) and blank group (unrepaired) randomly. The reconstructive effect in each group was evaluated by gross observation, alkaline phosphatase(ALP) detection of blood serum, histopathological observation, X-ray examination and SEM detection at 4th, 8th and 12th weeks postoperatively. Results In the experimental group there was more bone formation than in the control and the blank groups. The differences in reconstructive effect were statistically significant ( P