Enhancement of Surface Wettability via the Modification of Microtextured Titanium Implant Surfaces with Polyelectrolytes

Abstract

Micrometer- and submicrometer-scale surface roughness enhances osteoblast differentiation on titanium (Ti) substrates and increases bone-to-implant contact in vivo. However, the low surface wettability induced by surface roughness can retard initial interactions with the physiological environment. We examined chemical modifications of Ti surfaces [pretreated (PT), Ra ≥ 0.3 μm; sand blasted/acid etched (SLA), Ra ≥ 3.0 μm] in order to modify surface hydrophilicity. We designed coating layers of polyelectrolytes that did not alter the surface microstructure but increased surface ionic character, including chitosan (CHI), poly(l-glutamic acid) (PGA), and poly(l-lysine) (PLL). Ti disks were cleaned and sterilized. Surface chemical composition, roughness, wettability, and morphology of surfaces before and after polyelectrolyte coating were examined by X-ray photoelectron spectroscopy (XPS), contact mode profilometry, contact angle measurement, and scanning electron microscopy (SEM). High-resolution XPS spectra data validated the formation of polyelectrolyte layers on top of the Ti surface. The surface coverage of the polyelectrolyte adsorbed on Ti surfaces was evaluated with the pertinent SEM images and XPS peak intensity as a function of polyelectrolyte adsorption time on the Ti surface. PLL was coated in a uniform thin layer on the PT surface. CHI and PGA were coated evenly on PT, albeit in an incomplete monolayer. CHI, PGA, and PLL were coated on the SLA surface with complete coverage. The selected polyelectrolytes enhanced surface wettability without modifying surface roughness. These chemically modified surfaces on implant devices can contribute to the enhancement of osteoblast differentiation.

Mussel-inspired ultrathin film on oxidized Ti–6Al–4V surface for enhanced BMSC activities and antibacterial capability

“…21 Interestingly, J. H. Park et al observed and speculated that the incomplete coverage of chitosan, poly(Lglutamic acid) and poly(L-lysine) monolayers on titanium surface is due to the 0.15 M NaCl used to dissolve these polyelectrolytes, which results in the preferential attachment of Na + onto the negatively charged Ti surface. 23 However, this phenomenon is not observed in this study. It can be attributed to the PDA used prior to alginate/chitosan LBL self-assembly.…”

A review on the wettability of dental implant surfaces II: Biological and clinical aspects

“…Park et al [65] recently reported that different polyelectrolyte modifications prepared on the native oxide layers of machined and BAE Ti surfaces enhanced the hydrophilicity of the surface without changing its microtopography. Polyelectrolyte coatings shifted the hydrophobicity of the original Ti surfaces to a moderate hydrophilic state with a water CA between 40° and 60°, in contrast to the superhydrophilic modifications described previously ( i.e.…”

The responses to surface wettability gradients induced by chitosan nanofilms on microtextured titanium mediated by specific integrin receptors

“…Surface wettability has been modified through several methods including self-assembled monolayers, functional chemical species, multilayers with oppositely charged polymers, and topographical changes [20,21]. We previously demonstrated that surface wettability can be modified by polyelectrolyte coatings applied to sandblasted/acid-etched (SLA) surfaces [4].…”