Enhanced pH stability, cell viability and reduced degradation rate of poly(L-lactide)-based composite in vitro: effect of modified magnesium oxide nanoparticles

Abstract

The modified MgO nanoparticles (m-MgO-NPs) by a copolymer containing the malic acid and low molecular weight poly(L-lactide) (poly(L-lactide-co-malic acid), PLMA) have been successfully prepared. MgO nanoparticles (MgO-NPs) were coated by the PLMA and m-MgO-NPs were uniformly dispersed in the PLLA matrix to a novel biocomposite material (PLLA/m-MgO-NPs) with more excellent interface bonding and uniformer dispersion, compared to the PLLA/MgO-NPs. Compared to neat PLLA and PLLA/MgO-NPs film, the m-MgO-NPs not only shown the obvious neutralization effect on the acidic solution in the degradation of the PLLA and better hydrophilicity, but also exhibited the higher cell viability and decrease the toxicity to the cell in the degradation process of PLLA in vitro. In addition, m-MgO-NPs also reduced the degradation rate of the PLLA. The mechanisms for the excellent dispersion of nanoparticles, enhanced pH stability, reduced degradation rate of the PLLA and the cell viability in vitro in the case of PLLA/m-MgO-NPs have also been proposed and discussed in detail.

Polycondensation of a Perylene Bisimide Derivative and L-Malic Acid as Water-Soluble Conjugates for Fluorescent Labeling of Live Mammalian Cells

“…However, the main component of PBI–PMA, PMA, contains ester groups, which are prone to degradation in aqueous solutions (hydrolysis). And, the degradation of PBI–PMA can be auto-catalyzed by its own carboxyl groups [29]. Further, as we have confirmed with GPC measurements (Supplementary Materials Figure S1), the PBI–PMA degrades significantly at pH 8, which leads to the lower solubility and lower fluorescence intensity of PBI.…”

The Degradation Properties of MgO Whiskers/PLLA Composite In Vitro

“…However, few reports have focused on the effect of MgO contents on the degradation behavior of the composite during the decomposition process. Ma et al [ 19 ] obtained the n-MgO/PLLA composite by adding n-MgO modified by poly(ε-caprolactone) into a PLLA matrix, and the reduction of pH was suppressed to a certain extent, which was also demonstrated by us [ 22 ]. Luo et al [ 9 ] studied the in vitro degradation properties of the MgO whiskers (w-MgO)/PLLA composite; their work mainly focused on the effect of whiskers on PLLA degradation for a long decomposition period.…”

“…Magnesium oxide (MgO), another inorganic filler with good biocompatibility, and bioactive capacity that is not toxic, has attracted much attention [ 19 , 20 , 21 , 22 ] for polymer modification. In addition to the aforementioned advantages, the Mg 2+ released from MgO dissolving in water is beneficial to the protein synthesized via the activation of many enzymes, which contribute to the excellent bioactivity of MgO.…”

“…It has been reported that the dissolution of MgO in vitro prominently influences the solution pH through alkaline degradation [ 19 ]. Recently, the researchers utilized the different shapes of MgO [ 9 , 19 , 20 , 21 , 22 , 23 , 24 ] as fillers and introduced them to PLLA for preparing composites. The results mostly showed that the mechanical properties and thermal behavior of PLLA improved significantly with the presence of MgO fillers, which was also proved in our works [ 24 ].…”

Improving the Thermal and Mechanical Properties of Poly(l-lactide) by Forming Nanocomposites with an in Situ Ring-Opening Intermediate of Poly(l-lactide) and Polyhedral Oligomeric Silsesquioxane

“…However, improving the crystallinity is often not effective if only the temperature gradient and cooling rate are controlled, and the temperature cannot be controlled easily in real manufacturing. The final and maybe the most promising approach is to add some organic and/or inorganic particles as nucleating agents to the PLLA matrix, such as sodium stearate [30], nano-clays [31], graphite particles [32], triclosan nanoparticles [33], tungsten disulphide inorganic nanotubes (INT-WS 2 ) [34], or magnesium oxide nanoparticles [35]. Compounding with these particles by physical blending is a conventional method of fabricating PLLA composites and was proved to be convenient to improve the crystallization behavior of PLLA.…”