Plant leaves, insects and geckos are masters of adhesion or anti-adhesion by smartly designed refined surface structures with micro- and nano- ＇technologies＇. Understanding the basic principles in the design of the ...Plant leaves, insects and geckos are masters of adhesion or anti-adhesion by smartly designed refined surface structures with micro- and nano- ＇technologies＇. Understanding the basic principles in the design of the unique surface structures is of great importance in the manufacture or synthesis of micro- and nano- devices in MEMS or NEMS. This study is right inspired by this effort, focusing on the mechanics of wet adhesion between fibers having concave tips and a flat substrate via capillary forces. We show that the concave surface can effectively enhance the wet adhesion by reducing the effective contact angle of the fiber, firmly pinning the liquid bridge at its circumferential edge. A critical contact angle is identified below which the adhesion strength can achieve its maximum, being insensitive to the contact angle between the fiber and liquid. The analytical expression for the critical angle is derived. Then a tentative design for the profile of concave surfaces is proposed, considering the effects of chamfering size, deformation and buckling, etc. The effect of liquid volume on the wet adhesion of multiple-fiber system is also discussed.展开更多
目的:体外观察左氧氟沙星(LFX)涂敷导管对铜绿假单胞菌黏附、定植能力的影响,探讨LFX涂敷导管在铜绿假单胞菌导管相关感染中的应用价值。方法:制备LFX涂敷导管,测定LFX涂敷导管的体外药物累积释放度。实验分为LFX涂敷导管组和聚氯乙烯(P...目的:体外观察左氧氟沙星(LFX)涂敷导管对铜绿假单胞菌黏附、定植能力的影响,探讨LFX涂敷导管在铜绿假单胞菌导管相关感染中的应用价值。方法:制备LFX涂敷导管,测定LFX涂敷导管的体外药物累积释放度。实验分为LFX涂敷导管组和聚氯乙烯(PVC)导管组,2组导管分别浸没于5 mL 50%LB培养液中(含铜绿假单胞菌108 CFU/mL),37℃孵育6h、12h、24h、48h,在各时间点,分别于导管表面和导管培养液进行细菌计数。结果:LFX涂敷导管能够在2h内实现药物的快速释放,2h后LFX涂敷导管药物释放很少,甚至没有释放。LFX对实验菌PAO1的最小抑菌浓度(MIC)和最小杀菌浓度(MBC)分别为0.5mg/L、1.0mg/L;6h、12h、24h孵育时间点,LFX1∶3、LFX1∶6、LFX1∶9涂敷导管表面定植、黏附细菌培养均为阴性;且LFX1∶3、LFX1∶6、LFX1∶9涂敷导管在不同孵育时间点培养液的细菌数较PVC导管培养液的细菌数明显减少(P<0.05)。结论:LFX涂敷导管能有效抑制铜绿假单胞菌黏附、定植,提示LFX涂敷导管可作为预防铜绿假单胞菌导管相关感染的有效策略。展开更多
基金supported by the National Natural Science Foundation of China through Grant Nos 10628205,10732050 and10872115National Basic Research Program of China through Grant No 2007CB936803,and SRF-SEM for ROCS
文摘Plant leaves, insects and geckos are masters of adhesion or anti-adhesion by smartly designed refined surface structures with micro- and nano- ＇technologies＇. Understanding the basic principles in the design of the unique surface structures is of great importance in the manufacture or synthesis of micro- and nano- devices in MEMS or NEMS. This study is right inspired by this effort, focusing on the mechanics of wet adhesion between fibers having concave tips and a flat substrate via capillary forces. We show that the concave surface can effectively enhance the wet adhesion by reducing the effective contact angle of the fiber, firmly pinning the liquid bridge at its circumferential edge. A critical contact angle is identified below which the adhesion strength can achieve its maximum, being insensitive to the contact angle between the fiber and liquid. The analytical expression for the critical angle is derived. Then a tentative design for the profile of concave surfaces is proposed, considering the effects of chamfering size, deformation and buckling, etc. The effect of liquid volume on the wet adhesion of multiple-fiber system is also discussed.
文摘目的:体外观察左氧氟沙星(LFX)涂敷导管对铜绿假单胞菌黏附、定植能力的影响,探讨LFX涂敷导管在铜绿假单胞菌导管相关感染中的应用价值。方法:制备LFX涂敷导管,测定LFX涂敷导管的体外药物累积释放度。实验分为LFX涂敷导管组和聚氯乙烯(PVC)导管组,2组导管分别浸没于5 mL 50%LB培养液中(含铜绿假单胞菌108 CFU/mL),37℃孵育6h、12h、24h、48h,在各时间点,分别于导管表面和导管培养液进行细菌计数。结果:LFX涂敷导管能够在2h内实现药物的快速释放,2h后LFX涂敷导管药物释放很少,甚至没有释放。LFX对实验菌PAO1的最小抑菌浓度(MIC)和最小杀菌浓度(MBC)分别为0.5mg/L、1.0mg/L;6h、12h、24h孵育时间点,LFX1∶3、LFX1∶6、LFX1∶9涂敷导管表面定植、黏附细菌培养均为阴性;且LFX1∶3、LFX1∶6、LFX1∶9涂敷导管在不同孵育时间点培养液的细菌数较PVC导管培养液的细菌数明显减少(P<0.05)。结论:LFX涂敷导管能有效抑制铜绿假单胞菌黏附、定植,提示LFX涂敷导管可作为预防铜绿假单胞菌导管相关感染的有效策略。
