Monocyclic β-lactams loaded on hydroxyapatite: new biomaterials with enhanced antibacterial activity against resistant strains

• Published in: Scientific reports Vol. 7; no. 1; pp. 2712 - 12
• Main Authors: Giacomini, Daria, Torricelli, Paola, Gentilomi, Giovanna Angela, Boanini, Elisa, Gazzano, Massimo, Bonvicini, Francesca, Benetti, Emanuele, Soldati, Roberto, Martelli, Giulia, Rubini, Katia, Bigi, Adriana
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 02.06.2017; Nature Publishing Group; Nature Portfolio
• Subjects: 140/131; 639/301/54; 639/638/298/54; Anti-Bacterial Agents - chemical synthesis; Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - pharmacology; Antibacterial activity; Antibiotic resistance; Azetidines - chemistry; Azetidines - pharmacology; Bacteria; Bacteria - drug effects; Biocompatible Materials - chemistry; Biomaterials; Biomedical materials; Clinical isolates; Colonization; Drug Carriers; Drug Liberation; Durapatite - chemistry; Gram-negative bacteria; Humanities and Social Sciences; Humans; Hydroxyapatite; Mechanical loading; Methicillin; Microbial Sensitivity Tests; Molecular Structure; Monobactams - chemical synthesis; Monobactams - chemistry; Monobactams - pharmacology; multidisciplinary; Polarity; Science; Science (multidisciplinary); Spectroscopy, Fourier Transform Infrared
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-017-02943-2

The development of biomaterials able to act against a wide range of bacteria, including antibiotic resistant bacteria, is of great importance since bacterial colonization is one of the main causes of implant failure. In this work, we explored the possibility to functionalize hydroxyapatite (HA) nanocrystals with some monocyclic N-thio-substituted β-lactams. To this aim, a series of non-polar azetidinones have been synthesized and characterized. The amount of azetidinones loaded on HA could be properly controlled on changing the polarity of the loading solution and it can reach values up to 17 wt%. Data on cumulative release in aqueous solution show different trends which can be related to the lipophilicity of the molecules and can be modulated by suitable groups on the azetidinone. The examined β-lactams-HA composites display good antibacterial activity against reference Gram-positive and Gram-negative bacteria. However, the results of citotoxicity and antibacterial tests indicate that HA loaded with 4-acetoxy-1-(methylthio)-azetidin-2-one displays the best performance. In fact, this material strongly inhibited the bacterial growth of both methicillin resistant and methicillin susceptible clinical isolates of S. aureus from surgical bone biopsies, showing to be a very good candidate as a new functional biomaterial with enhanced antibacterial activity.