Chronic wounds are greatly health threatening owing to the increasing morbidity, and bacterial biofilm is a major cause of chronic wounds. The critical for bacterial biofilm eradication is overcome the barrier of extracellular polymeric substances (EPS) produced by the bacteria, and promote the diffusion of drugs within the biofilm. In this article, composite microneedles (MNs) of chitosan and zinc nitrate (CS‐Zn[II] MNs) were investigated to eradicate bacterial biofilm. The CS‐Zn(II) MNs combined the structure characteristic of MNs with the antibacterial properties of CS and Zn²⁺. The MNs can pierce the EPS due to the needle‐like structure, and can transport directly the CS and Zn²⁺ into the bacterial biofilm. The needle‐like structure of MNs also increased the contact area between drug carrier and bacterial biofilm nearly 14–23% comparing with membrane without needle‐like structure, and facilitated the diffusion of drugs. What is more, the synergistic effect of CS and Zn²⁺ make the CS‐Zn(II) MNs obtain excellent antibiofilm properties. Counting the colony forming units and bacterial live/dead staining tests confirmed the fascinating antibacterial abilities (up to 100% inhibition) and biofilm eradication properties, respectively, of the CS‐Zn(II) MNs. The inhibition zone test shown that the antibiofilm effect of MNs was superior to membrane and the antibiofilm effect of MNs was become increasingly obvious along with the increase of the treatment time. Besides, the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assays proved that the CS‐Zn(II) MNs possess brilliant cytocompatibility. These results indicate that the CS‐Zn(II) MNs are promising method for bacterial biofilm eradication.

中文翻译：

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用于细菌生物膜根除的壳聚糖/硝酸锌微针

由于发病率的增加，慢性伤口对健康构成了极大的威胁，而细菌生物膜是导致慢性伤口的主要原因。细菌生物膜根除的关键是克服细菌产生的细胞外聚合物（EPS）的屏障，促进药物在生物膜内的扩散。在本文中，研究了壳聚糖和硝酸锌 (CS-Zn[II] MNs) 的复合微针 (MNs) 以消除细菌生物膜。CS-Zn(II) MNs 将 MNs 的结构特征与 CS 和 Zn ²⁺的抗菌特性相结合。由于针状结构，MNs可以刺穿EPS，并可以直接运输CS和Zn ²⁺进入细菌生物膜。与没有针状结构的膜相比，MNs的针状结构还增加了药物载体与细菌生物膜的接触面积近14-23%，促进了药物的扩散。更重要的是，CS和Zn ^{2+的协同作用}使 CS-Zn(II) MNs 获得优异的抗生物膜性能。计数菌落形成单位和细菌活/死染色测试分别证实了 CS-Zn(II) MNs 令人着迷的抗菌能力（高达 100% 的抑制）和生物膜清除特性。抑菌圈试验表明，MNs的抗生物膜作用优于膜，并且随着处理时间的增加，MNs的抗生物膜作用越来越明显。此外，3-(4,5-二甲基噻唑-2-基)-2,5-二苯基溴化四唑 (MTT) 测定证明 CS-Zn(II) MNs 具有出色的细胞相容性。这些结果表明，CS-Zn(II) MNs 是一种有前途的细菌生物膜根除方法。