Centre for Chemistry and Biomedicine (CCB), Department of Pharmaceutical Technology, Institute of Pharmacy, University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria.
Institute of Food, Nutrition and Health, ETH Zürich, Schmelzbergstrasse 7, 8092 Zürich, Switzerland.
J Mater Chem B. 2024 Sep 25;12(37):9199-9205. doi: 10.1039/d4tb01122h.
Stimuli-responsive nanomaterials show promise in eradicating biofilm from implants. Peptidoglycan hydrolases (PGHs) are cationic antimicrobials that can be bioengineered to improve the targeting of persisters and drug-resistant bacteria. However, these molecules can be degraded before reaching the target and/or present limited efficacy against biofilm. Therefore, there is an urgent need to improve their potency. Herein, PGH-polyphosphate nanoparticles (PGH-PP NPs) are formed by ionotropic gelation between cationic PGHs and anionic polyphosphate, with the aim of protecting PHGs and delivering them at the target site triggered by alkaline phosphatase (AP) from biofilm. Optimized conditions for obtaining M23-PP NPs and GH15-PP NPs are presented. Size, zeta potential, and transmission electron microscopy imaging confirm the nanoscale size. The system demonstrates outstanding performance, as evidenced by a dramatic reduction in PGHs' minimum inhibitory concentration and minimum bactericidal concentration, together with protection against proteolytic effects, storage stability, and cytotoxicity towards the Caco-2 and HeLa cell lines. Time-kill experiments show the great potential of these negatively charged delivery systems in overcoming the staphylococcal biofilm barrier. Efficacy under conditions inhibiting AP proves the enzyme-triggered delivery of PGHs. The enzyme-responsive PGH-PP NPs significantly enhance the effectiveness of PGHs against bacteria residing in biofilm, offering a promising strategy for eradicating biofilm.
响应性纳米材料在消除植入物生物膜方面具有很大的应用前景。肽聚糖水解酶（PGHs）是阳离子型抗菌剂，可以通过生物工程改造来提高对持久性细菌和耐药菌的靶向性。然而，这些分子在到达靶标之前可能会被降解，并且/或者对生物膜的疗效有限。因此，迫切需要提高它们的效力。在此，通过阳离子 PGHs 与阴离子多聚磷酸盐之间的离子凝胶化形成 PGH-多磷酸盐纳米颗粒（PGH-PP NPs），目的是保护 PGHs 并在生物膜中的碱性磷酸酶（AP）触发下将其递送至靶位。提出了获得 M23-PP NPs 和 GH15-PP NPs 的优化条件。尺寸、Zeta 电位和透射电子显微镜成像证实了纳米级尺寸。该系统表现出出色的性能，表现在 PGHs 的最小抑菌浓度和最小杀菌浓度显著降低，同时具有抗蛋白水解作用、储存稳定性以及对 Caco-2 和 HeLa 细胞系的细胞毒性的保护作用。时间杀伤实验表明，这些带负电的递送系统在克服葡萄球菌生物膜屏障方面具有巨大的潜力。在抑制 AP 的条件下的功效证明了 PGHs 的酶触发递送。酶响应性 PGH-PP NPs 显著提高了 PGHs 对生物膜中细菌的有效性，为消除生物膜提供了一种有前途的策略。
