Designed a contrast pinhole detect testing including water leak method, electrical method and improved electrical method, and concluded that the water leak method is most suitable as the arbitration method, and recommended the national standard add the requirement on electrolytic liquid filling volume of electrical test in order to improve detection accuracy.
Condoms ; Latex ; Materials Testing ; methods ; Rubber

In China, the evaluation of hemocompatibility of biomaterials is limited to hemolysis, coagulation time,and the number and morphology of platelets adhered on biomaterials. The present research, however, is aimed to establish a method for evaluating the function of sheet biomaterials in platelet activation. Platelet activation caused by glass, polyvinyl chloride or polymethylvinylsiloxane sheets was evaluated by measuring alpha-granule membrane protein (GMP-140) in platelet poor plasma, using a reasonable blood-material contact model vibrating at different speed. The result showed that the difference in platelet activation was not significantly different among the three above-mentioned materials at 140r/m or 200r/m. However, when it comes to 230r/m, significant difference was observed among these three groups, with glass > polyvinyl chloride > polymethylvinylsiloxane. But the order was reversed at 270r/m, which may be due to the different interfacial tension of different materials. Therefore, the method is suitable to evaluate platelet activation caused by sheet biomaterials, but an appropriate vibrating speed should be chosen. The interfacial tension plays an important role in the model and should be considered for results assessment.
Biocompatible Materials ; Humans ; Materials Testing ; methods ; Platelet Activation ; Surface Properties

The favorable biocompatibility of dental biomaterial is very important, which guarantees the safety and effectiveness of its clinical application. The cytotoxicity test, as one of the biological evaluation screening tests, is known to be an important and frequently used method to evaluate biocompatibility of biomaterials. This text is devoted to an overview of the cytotoxicity test for dental materials.
Biocompatible Materials ; toxicity ; Biological Assay ; methods ; trends ; Dental Materials ; toxicity ; Humans ; Materials Testing ; methods

OBJECTIVETo investigate the impact of cuff pressure on airway leak pressure in laryngeal mask airway(LMA)Supreme and Flexible.

METHODSPatients about to have elective breast surgery were divided into Supreme group(35 cases)and Flexible group(33 cases). After general induction of anesthesia,LMA Supreme or Flexible was inserted by one anesthesiologist. We confirmed the LMA location,adjusted the cuff pressure,and recorded the peak airway leak pressures under different cuff pressures(10,20,30,40,and 50 cmH2O).

RESULTSIn Supreme group,peak airway leak pressures [(24.46±5.43),(25.11±5.51),(25.86±5.57),(26.17±5.72)cmH2O] under 20,30,40,and 50 cmH2O cuff pressure showed no significant difference(P>0.05)between each other,but significantly higher than that under 10 cmH2O cuff pressure(20.80±4.63)cmH2O(P<0.05). And in the Flexible group,peak airway leak pressures [(20.09±2.98),(20.70±3.08),(21.21±3.15)cmH2O] under 30,40,50 cmH2O cuff pressure also showed no significant difference(P>0.05)between each other,but significantly higher than those under 10 or 20 cmH2O cuff pressure [(17.52±2.39),(18.61±2.42)cmH2O]. Mean peak airway leak pressure [(25.40±5.52) cmH2O] of LMA Supreme was significantly higher than that of LMA Flexible(20.67±3.06)cmH2O(P<0.05).

CONCLUSIONSMean airway leak pressure of LMA Supreme is higher than LMA Flexible. The lowest cuff pressure to meet the tightness requirement with LMA Supreme is 20 cmH2O,which is lower than Flexible(30 cmH2O).

The major idea of this article is to discuss standardization and normalization for the product standard of medical devices. Analyze the problem related to the physical performance requirements and test methods during product standard drafting process and make corresponding suggestions.
Device Approval ; Equipment and Supplies ; standards ; Materials Testing ; methods ; Weights and Measures

This paper is based on the research and analysis of the existing related measuring methods, and aimed at the characteristics of equivalent artificial soft materials, and it also proposes a new adaptable test method to measure elastic modules. The modules are based on capacitive gate transducer and micrometer which suits for soft materials. Based on this proposed method, a micro feed mechanism has been designed. The same strain of soft materials under compress test was realized, and the feasibility of this method by analyzing the test results was testified.
Biocompatible Materials ; Biomechanical Phenomena ; Biomedical Engineering ; methods ; Computer Simulation ; Elastic Modulus ; Hardness ; Materials Testing ; methods

It is difficult to test the elastic modulus of the soft bio-anthropomorphic materials by using the general stretch-strain test method. With the equipment for a hardness testing system of bio-anthropomorphic materials and millesimal gauge, we introduce in this paper a compress-strain test method and carry out the related test-data curve-fitness. The test results indicate that this kind of method can be adopted in testing the elastic modulus of the soft bio-anthropomorphic materials and help to compare and distinguish the biomechanics equivalent between the tissues.
Biocompatible Materials ; Biomedical Engineering ; methods ; Computer Simulation ; Elastic Modulus ; Elasticity ; Hardness ; Humans ; Materials Testing ; methods

OBJECTIVETo study the durability of expanded polytetrafluoroethylene artificial heart valve (ePTFE AHV).

METHODSSix ePTFE AHVs were tested for 400 million times against accelerated fatigue using TH-2200 artificial heart valve exosomatic accelerated fatigue instrument. Hydromechanical parameters of fore-and-aft accelerated fatigue test of the 6 AHVs were obtained by TH-1200 artificial heart valve exosomatic pulsatile stream instrument.

RESULTS AND CONCLUSIONThe mean gradient pressure spanning the valve and the effective orific area of ePTFE AHVs did not undergo significant changes after fore-and-aft the fatigue test, but the regurgitation volume and regurgitation rate of ePTFE AHVs were reduced after the accelerated fatigue test, suggesting good durability of ePTFE AHV.

The immunoreaction caused by biomaterials or medical devices are even more concerned by people. It is necessary to establish the immune items in the biological evaluation of biomaterials and medical devices. And it is a tendency to use immune technique combined with molecular biological methods to evaluate the immunoreaction for biomaterials.
Biocompatible Materials ; adverse effects ; Equipment and Supplies ; adverse effects ; Immunity ; Materials Testing ; methods ; Toxicity Tests

Quantification of residual DNA in animal-derived biological scaffold materials is one of technical specifications for evaluating decellularization process and immunotoxicity risk. Up to now, there have been no standard methods available for quantification of residues DNA in animal-derived biological scaffold materials. In this study, a three-step method, including proteinase K digestion, DNA purification and determination of DNA using fluorescence assay, was designed for residual DNA quantification. A parallel recovery experiment of standard DNA using the same protocol to test article determination was used for adjusting final results of residuul DNA amount. DNA purification based on magnetic beads enabled the experiments to get high accuracy and repeatability. The validation experiment showed that the three-step method had high sensitivity up to 6.25ng of DNA per sample with good linearity (recovery curve R2 > 0.99) in the concentration range of 3. 125-100ng, and 25-400ng per sample. This method is useful for determining micro or trace amount DNA remained in the biomaterials.
Animals ; Biocompatible Materials ; chemistry ; DNA ; analysis ; isolation & purification ; Materials Testing ; methods ; Tissue Scaffolds ; chemistry