Study Of Bionic Needle With Both Drag Reduction And Antibacteria Based On Insect Mouthpart

Intramuscular injection and transfusion by syringe are commonly usedtechniques in clinical application. With the improvement of living standards,considerable attention has been paid on the safety and comfort of the injection bythe patients. According to the researches, pain of injection is mainly caused bypuncture resistance, which made of rupturing of the skin tissue during the initialstage of the injection and friction between needle and subcutaneous tissue duringthe process of injection. In addition, the infection occurs at the interface betweenthe syringe and surrounding tissues from the adhesion of bacterial. So the painlessantibacterial injection technique has significant scientific and market values.Mimicking the structure of the needling mouthpart of the insect, the study ofbionic needle is used to realize drag reduction and antibacterial injection techniquethrough modifying the configuration and the microstructure of the needle surface.Based on the existing research results, mouthparts structure and its biologicalmechanism has been analysed；the method of enhancement antibacterial effect ofbionic needle has been studied from the angle of biomaterials；to get the optimalsurface structure parameters of bionic needle, experimental optimization methodhas been adopted here；the pinpoint shape relation with puncture effect has beendiscussed. Mainly include four parts as following:(1) More insect mouthparts with the piercing and sucking function have beenstudied in this paper. Such as the piercing-sucking mouthparts of mosquito, cicadaand water skipper, scratching mouthparts of gadfly, and sting needles of bee etc. Bycomparing the mouthparts found, the biological needle surfaces have a variety ofnon-smooth structures, such as serrated, groovy, stripe, and triangular convex hulletc. Study on mechanism of bionic mouthpart drag reduction indicates that thebionic mouthpart could reduce the resistance by decreasing the contact area, changesliding friction into rolling friction and producing micro-vibration during theprocess of the needle piercing the muscle soft tissue.(2) Experiment results show that the best modification effect on the needlesurface obtained when reaction of the treated stainless steel needle with HCL、 AgNO3solutions. Then the wettability of the needle surfaces was modified usinghydrophile reagent and hydrophobic reagent respectively. For the antibacterialactivity test, Escherichia coli (E. coli) were used as test organism. The antibacterialactivity of the bionic needle was assessed by calculating the surface area of theinhibition zone against E. coli formed on agar medium. From the experiment resultwe can see that the original stainless steel needles doesn’t exhibit any antibacterialactivity, on the otherwise the bionic needles with hydrophile or hydrophobicsurfaces show antibacterial activity. And the antibacterial property ofsuper-hydrophobic surface is better than that of hydrophile one. According tosilicon membrane puncture test, the bionic needles with hydrophobic surfaces showdrag reduction effects.(3) Different bionic needles with spiral，concave，undee and serrated shapeshave been designed on No.16bionic needle and processed into that with the bionicnon-smooth surface by the laser technology. According to the national standardmethod for needle piercing property measurement, carry out silicon membranesingle factor puncture test of bionic needle and calculate the drag reduction rates ofthe bionic needles mentioned above to find the optimal structure size for thedifferent needles respectively. As a result, all the needles were found to have dragreduction effects. Through drag reduction mechanism analysis, it is found that thenon-smooth structure on the bionic needle surface made the contact area betweensmooth part and medium decreased. Therefore the drag reduction could be realized.(4) According to the national standard and the structure of the needlingmouthpart of the insect, different pinpoints with non-smooth structures have beendesigned. By means of silicon membrane puncture contrast test of needle tip forbase, the pierce drag of the bionic pinpoint is less than that of the original pinpoint.The relationship between the pinpoint inclined plane and puncture effect wasdiscussed by geometry finite element method, found the optimal structure size forthe pinpoint inclined planes.