Characterization of Magnesium-Polylactic Acid Films Casted on Different Substrates and Doped with Diverse Amounts of CTAB.

Margarita Hierro-Oliva,Verónica Luque-Agudo,Amparo M Gallardo-Moreno,M Luisa González-Martín

doi:10.3390/molecules26164811

Abstract

Polylactic acid (PLA) is a good candidate for the manufacture of polymeric biodegradable biomaterials. The inclusion of metallic particles and surfactants solves its mechanical limitations and improves its wettability, respectively. In this work, cetyltrimethylammonium bromide (CTAB) and magnesium particles have been incorporated into PLA films to evaluate the changes produced in the polymeric matrix cast on glass and silicone substrates. For this purpose, the surface of the films has been characterized by means of contact angle measurements and ToF-SIMS. Depth profiles and SEM images of the cross sections of the films have also been obtained to study their morphology. The results show that the CTAB in the polymer matrix with and without magnesium improves the wettability of the films, making them more suitable for cell adhesion. The higher the hydrophilicity, the higher the surfactant concentration. The depth profiles show, for the first time, that, depending on the surfactant concentration and the presence of Mg, there is a layer-like distribution near the surface where, in addition to the CTAB + PLA mixture, a surfactant exclusion zone can be seen. This new structure could be relevant in in vitro/in vivo situations when the degradation processes remove the film components in a sequential form.

Highlights

Polylactic acid (PLA) is undoubtedly one of the most valuable, biodegradable, bioabsorbable, and sustainable polymers
According to surface mass spectra, at cetyltrimethylammonium bromide (CTAB) concentrations above 5% (w/w), there is a noticeable presence of surfactant on the film surface
The presence of CTAB in the polymer matrix with and without magnesium improves the wettability of the films, making them more suitable for cell adhesion

Summary

Introduction

Polylactic acid (PLA) is undoubtedly one of the most valuable, biodegradable, bioabsorbable, and sustainable polymers. Its use mainly covers the manufacture of biomedical devices, and extends to different food, cosmetic, and pharmaceutical packaging applications [1]. Its interesting properties of non-toxicity and biocompatibility have prompted research to improve some of its other characteristics that appear as shortcomings in order to broaden its field of application. Its mechanical behavior is very limited [2]. Its low ductility is one of its main drawbacks as a packaging material. Even under low levels of stress, PLA tends to deform, permanently causing the loosening of the biodegradable fixation, and its low mechanical strength makes it unfeasible for a PLA orthopedic implant to maintain adequate performance until the bone grows sufficiently to restore its functionality [2]

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