title: The effect of alginate oligosaccharides on the mechanical properties of Gram-negative biofilms.
abstract: The influence of a novel, safe antibiofilm therapy on the mechanical properties of Pseudomonas aeruginosa and Acinetobacter baumannii biofilms in vitro was characterized. A multiscale approach employing atomic force microscopy (AFM) and rheometry was used to quantify the mechanical disruption of the biofilms by a therapeutic polymer based on a low-molecular weight alginate oligosaccharide (OligoG). AFM demonstrated structural alterations in the biofilms exposed to OligoG, with significantly lower Young's moduli than the untreated biofilms, (149 MPa vs 242 MPa; p < 0.05), a decreased resistance to hydrodynamic shear and an increased surface irregularity (Ra) in the untreated controls (35.2 nm ± 7.6 vs 12.1 nm ± 5.4; p < 0.05). Rheology demonstrated that increasing clinically relevant concentrations of OligoG (<10%) were associated with an increasing phase angle (δ) over a wide range of frequencies (0.1-10 Hz). These results highlight the utility of these techniques for the study of three-dimensional biofilms and for quantifying novel disruption therapies in vitro.
authors.affiliation: Tissue Engineering and Reparative Dentistry, Wound Biology Group, School of Dentistry, Cardiff University, Cardiff, UK.
authors.forename: Lydia C
authors.initials: LC
authors.lastname: Powell
authors.forename: Ahmed
authors.initials: A
authors.lastname: Sowedan
authors.forename: Saira
authors.initials: S
authors.lastname: Khan
authors.forename: Chris J
authors.initials: CJ
authors.lastname: Wright
authors.forename: Karl
authors.initials: K
authors.lastname: Hawkins
authors.forename: Edvar
authors.initials: E
authors.lastname: Onsøyen
authors.forename: Rolf
authors.initials: R
authors.lastname: Myrvold
authors.forename: Katja E
authors.initials: KE
authors.lastname: Hill
authors.forename: David W
authors.initials: DW
authors.lastname: Thomas
mesh_terms: D040981:Acinetobacter baumannii / Q000187:drug effects* / Q000502:physiology; D000464:Alginates / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D001422:Bacterial Adhesion / Q000187:drug effects; D018441:Biofilms / Q000187:drug effects*; D001696:Biomechanical Phenomena; D055119:Elastic Modulus; D057446:Hydrodynamics; D007795:Laminaria / Q000737:chemistry; D008826:Microbial Sensitivity Tests; D009844:Oligosaccharides / Q000737:chemistry / Q000494:pharmacology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000502:physiology; D012212:Rheology / Q000379:methods; D033081:Shear Strength / Q000187:drug effects; D013314:Stress, Mechanical
chemical_list: D000464:Alginates; D009844:Oligosaccharides