Rapid and Selective Discrimination of Gram-Positive and Gram-Negative Bacteria by Boronic Acid-Modified Poly(amidoamine) Dendrimer

• Published in: Analytical chemistry (Washington) 2019-03, Vol.91 (6), p.3929-3935
• Main Authors: Tsuchido, Yuji, Horiuchi, Ryosuke, Hashimoto, Takeshi, Ishihara, Kanako, Kanzawa, Nobuyuki, Hayashita, Takashi
• Format: Article
• Language: English
• Subjects: Acids; Agglomeration; Aggregates; Antibiotics; Bacteria; Chemistry; Crosslinking; Drug resistance; Fructose; Gram-negative bacteria; Gram-positive bacteria; pH effects
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/acs.analchem.8b04870

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.