Hutapea, Parsaoran; Ren, Fei; Darvish, Kurosh; Tehrani, Rouzbeh Afsarmanesh (Temple University. Libraries, 2018)
      The needle-based procedures are usually considered minimally invasive. However, in insertion into soft tissues such as brain and liver, the tissue damage caused by needle insertion can be very significant. From the literature, it has been known that reduction in needle insertion and extraction forces as well as tissue deformation during the insertion results in less invasive procedure. This work aims to design and develop a new bioinspired design for surgical needles which reduce the insertion and extraction forces of the needle, and its damage to the tissue. Barbs in honeybee stinger decrease its insertion force significantly. Inspired by that finding, a new honeybee-inspired needle was designed and developed, and its insertion mechanics was studied. To study the insertion mechanics of honeybee-inspired needle, insertion tests into artificial and biological tissues were performed using both honeybee-inspired and conventional needles. The barb design parameters effects on needle forces were studied through multiple insertion and extraction tests into PVC gels. The design parameters values of the barbs were experimentally modified to further reduce the ultimate insertion and extraction forces of the needle. Bioinspired needle with modified barb design parameters values reduces the insertion force by 35%, and the extraction force by 20%. To show the relevance, the insertion tests into bovine liver and brain tissue were performed. Our results show that there was a 10-25% decrease in the insertion force for insertions into bovine brain, and a 35-45% reduction in the insertion force for insertions into the bovine liver using the proposed bioinspired needles. The bioinspired and conventional needles were manufactured in different scales and then used to study the size scale effect on our results. To do so, the insertion tests into tissue-mimicking PVC gels and liver tissues were performed. The results obtained for different sizes of the needle showed 25-46% decrease in the insertion force. The tissue deformations study was conducted to measure tissue deformation during the insertion using digital image correlation. The tissue deformation results showed 17% decrease in tissue deformation using barbed needles. A histological study was performed to accurately measure the damage caused by needle insertion. Our results showed 33% less tissue damage using bioinspired needles. The results of the histological study are in agreement with our hypothesis that reducing needle forces and tissue deformation lead to less invasive percutaneous procedures.