Department of Materials and Life Sciences, Faculty of Science and Technology , Sophia University , 7-1 Kioi-cho , Chiyoda-ku , Tokyo 102-8554 , Japan.
Cooperative Department of Veterinary Medicine, Faculty of Agriculture , Tokyo University of Agriculture and Technology , 3-5-8 Saiwai-cho , Fuchu-shi , Tokyo 183-8509 , Japan.
Anal Chem. 2019 Mar 19;91(6):3929-3935. doi: 10.1021/acs.analchem.8b04870. Epub 2019 Feb 4.
There is an urgent need to develop a rapid and selective method for the detection of bacteria because delayed diagnosis and the overuse of antibiotics have triggered drug resistance in bacteria. To this end, we prepared boronic acid-modified poly(amidoamine) generation 4 (B-PAMAM(G4)) dendrimer as cross-linking molecules that form aggregates with bacteria. Within 5 min of adding B-PAMAM(G4) dendrimer solution to a bacterial suspension, large aggregates were observed. Interestingly, the aggregate formation with various bacteria was pH-dependent. In basic pH, both Gram-positive and Gram-negative bacteria formed aggregates, but in neutral pH, only Gram-positive bacteria formed aggregates. We revealed that this bacteria-selective aggregation involved the bacterial surface recognition of the phenylboronic acid moiety of B-PAMAM(G4) dendrimer. In addition, we demonstrated that the spherical structure of B-PAMAM(G4) was one of the important factors for the formation of large aggregates. The aggregation was also observed in the presence of ≤10 mM fructose. B-PAMAM(G4) dendrimer is expected to be a powerful tool for the rapid and selective discrimination between Gram-positive and Gram-negative bacteria.
因为延迟诊断和抗生素的过度使用已经引发了细菌的耐药性，所以迫切需要开发一种快速且有选择性的细菌检测方法。为此，我们制备了硼酸修饰的聚（酰胺-胺）四代（B-PAMAM（G4））树枝状大分子作为交联分子，与细菌形成聚集体。将 B-PAMAM（G4）树枝状大分子溶液加入细菌悬浮液中 5 分钟内，即可观察到大量聚集体的形成。有趣的是，各种细菌的聚集形成与 pH 值有关。在碱性 pH 值下，革兰氏阳性菌和革兰氏阴性菌都形成聚集体，但在中性 pH 值下，只有革兰氏阳性菌形成聚集体。我们揭示了这种具有细菌选择性的聚集涉及到 B-PAMAM（G4）树枝状大分子中苯硼酸部分对细菌表面的识别。此外，我们证明了 B-PAMAM（G4）的球形结构是形成大聚集体的重要因素之一。在存在≤10 mM 果糖的情况下，也观察到了聚集。B-PAMAM（G4）树枝状大分子有望成为快速、选择性区分革兰氏阳性菌和革兰氏阴性菌的有力工具。
