Abstract
The final purpose of this research is to develop a painless microneedle which is mimicking the size of female mosquito′s labium to mitigate pain for diabetic patients. However, the decreasing of outer diameter will affect inner diameter, rigidity and pressure in inner tube. The inner diameter and the rigidity of the needle will decrease while pressure loss will increase. In order to design painless microneedle which fulfilled painless, high-rigid and low-pressure loss, we need a pain evaluation test to determine the marginal outer diameter size of microneedle. Here, a pain evaluation test through stress assessment test has been proposed. However, this pain evaluation test is not a direct method to evaluate pain. In this study, we focused on Substance P (SP), which is one of pain transmitter. The SP has been proven expressed only at the stimulated region after simulated mouse skin with both chemical irritation and physical irritation. Therefore, we conducted an experiment by injected mouse skin with various diameter sizes of needle and determine the best diameter size by calculating the quantity of expressed SP by using image processing.
