Effect of honeybee stinger and its microstructured barbs on insertion and pull force.
Worker honeybee is well-known for its stinger with microscopic backward-facing barbs for self-defense. The natural geometry of the stinger enables painless penetration and adhesion in the human skin to deliver poison. In this study, Apis cerana worker honeybee stinger and acupuncture microneedle (as a barbless stinger) were characterized by Scanning Electron Microscope (SEM). The insertion and pull process of honeybee stinger into rabbit skin was performed by a self-developed mechanical loading equipment in comparison with acupuncture needle. In order to better understand the insertion and pull mechanisms of the stinger and its barbs in human multilayer skin, a nonlinear finite element method (FEM) was conducted. Experimental results showed that the average pull-out force of the stinger was 113.50mN and the average penetration force was only 5.75mN. The average penetration force of the stinger was about one order of magnitude smaller than that of an acupuncture microneedle while the average pull-out force was about 70 times larger than that of an acupuncture microneedle. FEM results showed that the stress concentrations were around the stinger tip and its barbs during the insertion process. The barbs were jammed in and torn the skin during the pull process. The insertion force of the stinger was greatly minimized due to its ultrasharp stinger tip and barbs while the pull force was seriously enhanced due to the mechanical interlocking of the barbs in the skin. These excellent properties are mainly a result of optimal geometry evolved by nature. Such finding may provide an inspiration for the further design of improved tissue adhesives and micro-needles for painless transdermal drug delivery and bio-signal recording.
Guangdong Provincial Key Laboratory of Sensor Technology and Biomedical Instrument, Sun Yat-Sen University, Guangzhou 510006, PR China; Department of Medical Equipment, Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510150, China.
Jintian
J
Ling
Guangdong Provincial Key Laboratory of Sensor Technology and Biomedical Instrument, Sun Yat-Sen University, Guangzhou 510006, PR China.
Zhenhua
Z
Song
Guangdong Provincial Key Laboratory of Sensor Technology and Biomedical Instrument, Sun Yat-Sen University, Guangzhou 510006, PR China.
Jiarui
J
Wang
Guangdong Provincial Key Laboratory of Sensor Technology and Biomedical Instrument, Sun Yat-Sen University, Guangzhou 510006, PR China.
Keyun
K
Chen
Guangdong Provincial Key Laboratory of Sensor Technology and Biomedical Instrument, Sun Yat-Sen University, Guangzhou 510006, PR China.
Jiyu
J
Li
Guangdong Provincial Key Laboratory of Sensor Technology and Biomedical Instrument, Sun Yat-Sen University, Guangzhou 510006, PR China.
Shujia
S
Xu
Guangdong Provincial Key Laboratory of Sensor Technology and Biomedical Instrument, Sun Yat-Sen University, Guangzhou 510006, PR China.
Lei
L
Ren
Guangdong Provincial Key Laboratory of Sensor Technology and Biomedical Instrument, Sun Yat-Sen University, Guangzhou 510006, PR China.
Zhipeng
Z
Chen
Guangdong Provincial Key Laboratory of Sensor Technology and Biomedical Instrument, Sun Yat-Sen University, Guangzhou 510006, PR China.
Dianwen
D
Jin
Guangdong Provincial Key Laboratory of Sensor Technology and Biomedical Instrument, Sun Yat-Sen University, Guangzhou 510006, PR China. Electronic address: jianglel@mail.sysu.edu.cn.
Lelun
L
Jiang
D000818:Animals; D001516:Bees / Q000033:anatomy & histology*; D001733:Bites and Stings; D008855:Microscopy, Electron, Scanning; D009339:Needles; D055585:Physical Phenomena; D011817:Rabbits; D012867:Skin
Barb; FEM; Microneedle; Penetration Force; Pull Force; Stinger