Bacterial Response to the Surface Aging of PLA Matrices Loaded with Active Compounds

Abstract

The use of active components in biomaterials improves the properties of existing ones and makes it possible to obtain new devices with antibacterial properties that prevent infections after implantation, thus guaranteeing the success of the implant. In this work, cetyltrimethylammonium bromide (CTAB) and magnesium particles were incorporated into polylactic acid (PLA) films to assess the extent to which progressive aging of the new surfaces resists bacterial colonization processes. For this purpose, the films’ surface was characterized by contact angle measurements, ToF-SIMS and AFM, and adhesion, viability and biofilm growth of Staphylococcus epidermidis bacteria on these films were also evaluated. The results show that the inclusion of Mg and CTAB in PLA films changes their surface properties both before and after aging and also modifies bacterial adhesion on the polymer. Complete bactericidal activity is exhibited on non-degraded films and films with CTAB. This antibacterial behavior is maintained after degradation for three months in the case of films containing a higher amount of CTAB.

Influence of post-processing on the adhesion of dual-species biofilm on polylactic acid obtained by additive manufacturing

“… Fernández-Grajera et al (2022) evaluated the influence of aging on microbial adhesion of PLA incorporated with cetyltrimethylammonium bromide (CTAB) and magnesium and observed that aging increased microbial adhesion on the surface after 3 months (p > 0.05) and further reported that there was no influence of aging on the hydrophobicity of the material ( Fernández-Grajera et al, 2022 ), which differs from this study since aging reduced the control group's CA and surface roughness. Despite not having performed PP techniques, the results differ from those found in this study in which the adhesion of C. albicans (p = 0.563) and S. mutans (p = 0.813) did not change as a function of 6-month aging.…”

“…Annealing the sample is a technique for performing thermal PP, which reduces the residual thermal stresses between layers from the printing process and promotes the viscoelastic relaxation of the polymer with a consequent filling of the voids between layers and pores with reduced surface roughness ( Gao et al, 2020 , Singh et al, 2019 ). In this study, thermal PP did not reduce surface roughness statistically significantly, since this method increases the degree of crystallinity when performed at temperatures above the glass transition temperature (Tg) ranging from 55 to 65 °C, which can alter the mechanical properties such as flexural strength and roughness ( Fernández-Grajera et al, 2022 , Meng et al, 2012 ).…”

“…It can be performed by the thermal aging technique, which consists of the complete immersion of the sample in water at a given temperature and time, to simulate the use term ( Barrasa et al, 2021 , Bechtel et al, 2022 , Bergaliyeva et al, 2022 ). The rough, porous surface and the biodegradability of PLA, accelerate aging leading to reduced mechanical performance and altered surface, which may favor the growth of microbial adhesion ( Barrasa et al, 2021 , Bechtel et al, 2022 , Bergaliyeva et al, 2022 , Fernández-Grajera et al, 2022 ).…”