Reduction of bacterial attachment on hydroxyapatite surfaces: Using hydrophobicity and chemical functionality to enhance surface retention and prevent attachment

Amphiphilic macromolecules (AMs) create an anti-attachment layer on surface of hydroxyapatite (HAP) that prevents bacterial adhesion and colonization. [Display omitted] •Amphiphilic macromolecules were used to inhibit bacterial colonization on enamel.•Structure activity studies were done to optimize efficacy of the macromolecules.•Phosphates display stronger chelating properties than carboxylates.•Increasing the polymers degree of hydrophobicity increases deposition and retention.•The efficacy of the macromolecules against gram-positive bacteria was evaluated. Water-soluble, linear polymers with high-acid functionality are commonly used in oral care formulations to provide benefits such as bioactive complexation and delivery, as well as inhibition of the bacteria deposition and colonization, commonly referred to as ‘anti-attachment’. Unfortunately, structure-activity relationship (SAR) studies of these polymers are scarce, thus, a systematic approach to design polymers with a desired property (e.g. anti-attachment) is limited. Multifunctional anti-attachment amphiphilic molecules (AMs) featuring a sugar backbone, hydrophobic arms, a poly(ethylene glycol) tail, and a chemical anchor effectively deposited on soft ceramic surfaces and reduced bacterial adhesion. The chemical compositions of the AMs were fine-tuned to better coordinate with dental enamel surfaces and prevent bacterial colonization. A graft-to approach was used to investigate the effect of the chemical anchor on AM deposition and retention. The chemical composition, absorption/desorption, and wettability properties of the bioactives and bioactive-coated surfaces were investigated using nuclear magnetic resonance, X-ray photon spectroscopy, quartz crystal microbalance, and contact angle. In addition, the ability of the AMs to provide anti-bacterial attachment on a simulated enamel surface was evaluated in vitro using bacterial repulsion assays. The SAR between surface retention and anti-attachment properties of the AMs demonstrates the feasibility and tunability of using these polymers as bioactive agents that provide anti-attachment benefits on dental enamel surfaces.