Objective: A minimally invasive hollow in-plane microneedle with a cladding structure is designed to improve the mechanical strength. Methods: The traditional weak stack structure has been changed into a cladding structure, and the effectiveness has been validated through finite element analysis. The prototypes of the microneedles were batch manufactured by the integrated micromachining process with no need to assemble. Results: Compared to our previously reported microneedle with the weak stack structure, the cladding microneedle in this paper shows 263% improvement in bonding strength (6.4±0.30 N) and 36.5% improvement in buckling strength (2.8±0.07 N). In addition, the fabricated microneedle will not fail during insertion into the fresh and dehydrated pig skin with a satisfying safety factor (1.55). Conclusion: A novel structure of hollow microneedle was developed and fabricated by microfabrication technology. The improvement in mechanical strength is obvious. Significance: The microneedle has great mechanical property and good potential for wider applications in human skin.

中文翻译：

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具有包层结构的微创空心微针：超薄但坚固，可批量生产

目的：设计一种具有包层结构的微创空心平面微针，以提高机械强度。方法：将传统的弱叠层结构改为包层结构，并通过有限元分析验证其有效性。微针的原型是通过集成微加工工艺批量制造的，无需组装。结果：与我们之前报道的具有弱堆叠结构的微针相比，本文中的包层微针的结合强度提高了 263% (6.4±0.30 N)，屈曲强度提高了 36.5% (2.8±0.07 N)。此外，制成的微针在插入新鲜脱水的猪皮时不会失效，安全系数（1.55）令人满意。结论：采用微细加工技术开发并制造了一种新型结构的空心微针。机械强度的提高是明显的。意义：该微针具有良好的力学性能，具有在人体皮肤上更广泛应用的良好潜力。