Fabrication and characteristics of anti-inflammatory magnesium hydroxide incorporated PLGA scaffolds formed with various porogen materials

Abstract

Poly(D,L-lactic-co-glycolic acid) (PLGA) has been widely used as a biodegradable polymer in the fabrication of porous polymer scaffolds, but it is hydrolyzed into acidic by-products such as glycolic acid and lactic acid in the human body. Magnesium hydroxide nanoparticles (Mg-NPs) were incorporated into a PLGA scaffold in order to neutralize the acidic environment caused by the hydrolysis of PLGA, thereby reducing the cytotoxicity and inflammatory response. In this study, three-dimensional porous scaffolds blended with 30% Mg-NP were fabricated using gas foaming (PLGA/Mg/NaHCO3), salt leaching (PLGA/Mg/NaCl), and freeze drying (PLGA/Mg/Ice), and their structures, morphologies, pH change, thermal properties, and mechanical properties were analyzed by Fourier transform infrared spectroscopy, scanning electron microscopy, pH meter, thermogravimetric analysis, and a universal testing machine. The porosity of the PLGA/Mg/Ice scaffold was higher at about 10-13 wt% than those of the PLGA/Mg/NaCl or PLGA/Mg/NaHCO3 scaffolds. The Mg-NP content of the PLGA/Mg/NaHCO3 scaffold remained lower than those of the other scaffolds at about 63%. As a result of this loss of Mg-NP, the PLGA/Mg/NaHCO3 scaffold was confirmed to have lower cell viability (about 70%) than the PLGA/Mg/Ice scaffold (about 100%), owing to the reduced neutralizing effect. Although the PLGA/Mg/Ice and PLGA/Mg/NaCl scaffolds showed similar cell viability, the NaCl of the PLGA/Mg/NaCl scaffold exhibited slight toxicity in the body. The expression level of interleukin-6 (IL-6) was significantly decreased in the PLGA/Mg/Ice scaffold than in the PLGA/Ice scaffold, but the PLGA/Mg/Ice scaffold exhibited an IL-6 expression level that was about 10% lower than that of the PLGA/Mg/ NaCl scaffold. Consequently, the addition of Mg-NP/Ice could conceivably reduce the expression level of IL-6 in PLGA scaffolds. This anti-inflammatory PLGA/Mg/Ice scaffold is therefore expected to show great promise when used as a template in tissue engineering.