An array of porous microneedles (PMNs) made of biodegradable poly(lactic-co-glycolic acid) (PLGA) is fabricated by a combination of molding and freeze-drying methods. The optimized mixture of PLGA and 1,4-dioxane is poured into a mold of a microneedle array, followed by the freezing and sublimation of the frozen particles of 1,4-dioxane, a procedure that left an interconnecting porous structure in the PLGA with a porosity around 50%. The mechanical strength of the PMN made of PLGA (PLGA-PMN) is reinforced by modification with carboxymethylcellulose (CMC), resulting in sufficient strength enough for insertion into an excised porcine skin. The transdermal resistance is significantly decreased by the CMC-modified PLGA-PMN, which would improve the efficiency and safety of DC current-based transdermal techniques, including the electrical monitoring of the skin condition and iontophoresis for drug delivery and medical diagnosis.

中文翻译：

---

用于电动皮肤贴片的可生物降解多孔微针

由可生物降解的聚多孔微针（中性粒细胞）的阵列（乳酸-共-乙醇酸）（PLGA）是通过模塑和冷冻干燥方法的组合制造的。将 PLGA 和 1,4-二恶烷的优化混合物倒入微针阵列模具中，然后冷冻和升华 1,4-二恶烷的冷冻颗粒，该过程在 PLGA 中留下相互连接的多孔结构孔隙率约 50%。由 PLGA (PLGA-PMN) 制成的 PMN 的机械强度通过用羧甲基纤维素 (CMC) 进行改性得到增强，从而产生足够的强度以插入切除的猪皮。CMC修饰的PLGA-PMN显着降低了透皮电阻，这将提高基于直流电流的透皮技术的效率和安全性，