School of Pharmacy, University of Nottingham, University Park, Nottingham NG7 2RD, UK.
Biomater Sci. 2019 Sep 24;7(10):4099-4111. doi: 10.1039/c9bm00773c.
Many debilitating infections result from persistent microbial biofilms that do not respond to conventional antibiotic regimens. A potential method to treat such chronic infections is to combine agents which interfere with bacterial biofilm development together with an antibiotic in a single formulation. Here, we explore the use of a new bioresponsive polymer formulation derived from specifically modified alginate nanoparticles (NPs) in order to deliver ciprofloxacin (CIP) in combination with the quorum sensing inhibitor (QSI) 3-amino-7-chloro-2-nonylquinazolin-4(3H)-one (ACNQ) to mature Pseudomonas aeruginosa biofilms. The alginate NPs were engineered to incorporate a pH-responsive linker between the polysaccharide backbone and the QSI, and to encapsulate CIP via charge-charge interactions of the positively-charged drug with the carboxyl residues of the alginate matrix. In this way, a dual-action release of antibiotic and QSI was designed for the low-pH regions of a biofilm, involving cleavage of the QSI-linker to the alginate matrix and reduced charge-charge interactions between CIP and the polysaccharide as the alginate carboxyl side-chains protonated. When tested in a biofilm model the concomitant release of CIP + QSI from the pH-responsive nanoparticles significantly reduced the viability of the biofilm compared with CIP treatment alone. In addition, the alginate NPs were shown to penetrate deeply into P. aeruginosa biofilms, which we attribute in part to the charges of the NPs and the release of the QSI agent. Finally, we tested the formulation in both a 2D keratinocyte and a 3D ex vivo skin infection model. The dual-action bio-responsive QSI and CIP release nanoparticles effectively cleared the infection in the latter, suggesting considerable promise for combination therapeutics which prevent biofilm formation as well as effectively killing mature P. aeruginosa biofilms.
许多使人衰弱的感染是由持续性微生物生物膜引起的，而这些生物膜对常规抗生素疗法没有反应。一种治疗此类慢性感染的潜在方法是将干扰细菌生物膜发育的试剂与抗生素结合在单一制剂中。在这里，我们探索了使用源自特定修饰的海藻酸钠纳米颗粒（NPs）的新型生物响应性聚合物制剂，以便将环丙沙星（CIP）与群体感应抑制剂（QSI）3-氨基-7-氯-2-壬基喹唑啉-4（3H）-one（ACNQ）联合递送至成熟的铜绿假单胞菌生物膜中。海藻酸钠 NPs 经过工程设计，在多糖主链和 QSI 之间包含 pH 响应性连接体，并通过带正电荷的药物与海藻酸钠基质的羧基残基之间的电荷-电荷相互作用来包封 CIP。通过这种方式，设计了一种针对生物膜低 pH 区域的抗生素和 QSI 的双重作用释放，涉及 QSI-连接体到海藻酸钠基质的裂解以及海藻酸钠侧链质子化时 CIP 与多糖之间的电荷-电荷相互作用降低。在生物膜模型中进行测试时，与单独使用 CIP 相比，pH 响应性纳米颗粒中 CIP+QSI 的同时释放显著降低了生物膜的活力。此外，海藻酸钠 NPs 被证明可以深入穿透铜绿假单胞菌生物膜，我们部分归因于 NPs 的电荷和 QSI 试剂的释放。最后，我们在二维角质形成细胞和 3D 离体皮肤感染模型中测试了该制剂。双重作用的生物响应性 QSI 和 CIP 释放纳米颗粒有效地清除了后者的感染，这表明联合治疗具有很大的潜力，既可以防止生物膜形成，又可以有效地杀死成熟的铜绿假单胞菌生物膜。
