The synergistic effect of mechanical vibration for skin puncturing using polymeric microneedles

The transdermal delivery effect of polymeric microneedles can be significantly improved with the aids of synergetic vibration. The finite element simulation software ANSYS was used to explore the skin puncturing results of microneedles under different vibration frequencies. The dynamic mechanical properties of polymeric microneedles and human skin were also investigated. Meanwhile, puncturing experiments were also performed under different vibration frequencies on abdomen of female mice using polymeric microneedles with different lengths. The results showed that the peak value of maximum equivalent stress and the plastic deformation of skin were the smallest at the vibrative frequency of 200 Hz. The maximum equivalent stresses presented 20%–50% decreases during the second puncturing cycle. Moreover, the puncturing result of longer microneedles (550 μm) is much better than that of shorter ones (350 μm) under the same vibration frequency. The average bottom diameter and penetration depth of the microchannel obtained under the conditions of 200 Hz vibration and 550 μm height microneedles were 671.03 and 367.55 μm, respectively. These results provided an experimental basis to verify the effectiveness of mechanical vibration for skin puncturing.