Du Guangsheng, Zhang Zhihua, He Penghui, Zhang Zhibing, Sun Xun
West China School of Pharmacy, Sichuan University, Chengdu, 610041, China.
School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
J Mech Behav Biomed Mater. 2021 May;117:104384. doi: 10.1016/j.jmbbm.2021.104384. Epub 2021 Feb 10.
Precise characterization of the mechanical properties of polymeric microneedles is crucial for their successful penetration into skin and delivery of the loaded active ingredients. However, most available strategies for this purpose are based on compression of the whole patch, which only provide the average rupture force of the needles and can not give information on the variations across individual microneedles in the patch. In this study, we determined the mechanical strength of individual microneedles of two types of hyaluronic acid microneedles with or without loaded model drugs using a micromanipulation technique. The applied force as a function of displacement of the microneedles was recorded, which was used to determine the rupture displacement, rupture force, and then to derive and calculate normal stress-deformation curve, rupture stress and Young's modulus of individual microneedles. The obtained data suggest that the molecular weight of the polymer and the loading of drug into the microneedles can significantly affect the rupture behavior and mechanical properties of the microneedles, which provides a foundation for preparing sufficiently strong microneedles for controlled drug delivery.
精确表征聚合物微针的力学性能对于其成功刺入皮肤并递送负载的活性成分至关重要。然而，目前大多数用于此目的的策略都是基于对整个贴片的压缩，这只能提供针的平均破裂力，无法给出贴片内单个微针之间变化的信息。在本研究中，我们使用微操纵技术测定了两种载有或未载有模型药物的透明质酸微针中单个微针的机械强度。记录了微针位移函数的作用力，用于确定破裂位移、破裂力，进而推导并计算单个微针的正应力-变形曲线、破裂应力和杨氏模量。所得数据表明，聚合物的分子量和药物在微针中的负载量可显著影响微针的破裂行为和力学性能，这为制备足够坚固的用于控释给药的微针奠定了基础。
