Background: The development of nanogels has become an attractive strategy to enhance the antibacterial activity performance of bacteria. Methods: The ciprofloxacin composite nanogels were successfully prepared by electrostatic interaction between gelatin (positive charge) and CMC (negative charge) with the help of sodium tripolyphosphate (TPP) as ionic crosslinkers, to increase the antibacterial activity of ciprofloxacin against Staphylococcus aureus (S. aureus) mastitis infection. The formulation screening, characterization, in vitro release, antibacterial activity, and biosafety were studied. Results: The optimized formulation was fabricated of 20 mg/mL (CMC) and 50mg/mL (gelatin). The optimized ciprofloxacin composite nanogels were homogenous canary yellow suspension with a sedimentation rate of 1 and were incorporated in nano-sized cross-linked polymeric networks. The particle sizes were distributed as, 402.7±1.3 nm, PDI of 0.12±0.01, ZP of -24.5±0.2mv, EE of 74.28%±0.03%, LC of 20.5%±0.05%. Scanning electron microscope images revealed that ciprofloxacin might be incorporated in nano-sized cross-linked polymeric networks. Fourier transform infrared showed that the spontaneous electrostatic interactions between CMC and gelatin produce the network structure and form the composite nanogels. Meanwhile, in vitro release study showed that ciprofloxacin composite nanogels had sustained-release performances. The ciprofloxacin composite nanogels had shown better antibacterial activity against SCV 102 isolate than S. aureus ATCC 29213 and S. aureus 101isolates. The biosafety studies suggested the great promise of the injectable ciprofloxacin composite nanogels as a biocompatible breast injection. Conclusion: This study will afford a potential approach for developing injectable ciprofloxacin-loaded gelatin-CMC composite nanogels for cow S. aureus mastitis therapy.

中文翻译：

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注射用环丙沙星明胶-羧甲基纤维素钠复合纳米凝胶的设计、结构测定及抑菌活性

背景：纳米凝胶的开发已成为增强细菌抗菌活性性能的有吸引力的策略。方法：以三聚磷酸钠（TPP）为离子交联剂，通过明胶（正电荷）与CMC（负电荷）之间的静电相互作用成功制备环丙沙星复合纳米凝胶，以提高环丙沙星对金黄色葡萄球菌（S. aureus）的抗菌活性。金黄色葡萄球菌）乳腺炎感染。研究了制剂筛选、表征、体外释放、抗菌活性和生物安全性。结果：优化的制剂由 20 mg/mL (CMC) 和 50mg/mL（明胶）制成。优化的环丙沙星复合纳米凝胶是均匀的金丝雀黄色悬浮液，沉降率为 1，并被纳入纳米尺寸的交联聚合物网络中。粒径分布为，402.7±1.3nm，PDI为0.12±0.01，ZP为-2​​4.5±0.2mv，EE为74.28%±0.03%，LC为20.5%±0.05%。扫描电子显微镜图像显示环丙沙星可能被纳入纳米尺寸的交联聚合物网络中。傅里叶变换红外显示CMC与明胶之间的自发静电相互作用产生网络结构并形成复合纳米凝胶。同时，体外释放研究表明，环丙沙星复合纳米凝胶具有缓释性能。环丙沙星复合纳米凝胶对 SCV 102 分离株的抗菌活性优于 S. 金黄色葡萄球菌 ATCC 29213 和金黄色葡萄球菌 101 分离株。生物安全性研究表明可注射的环丙沙星复合纳米凝胶作为生物相容性乳房注射剂具有巨大的前景。结论：本研究将为开发用于治疗奶牛金黄色葡萄球菌乳腺炎的可注射环丙沙星明胶-CMC 复合纳米凝胶提供一种潜在的方法。