In Vitro Degradation of Electrospun Poly(Lactic-Co-Glycolic Acid) (PLGA) for Oral Mucosa Regeneration

Abstract

Poly(lactic-co-glycolic acid) (PLGA) has been used in the field of tissue engineering as a scaffold due to its good biocompatibility, biodegradability and mechanical strength. With the aim to explore the degradability of PLGA electrospun nonwoven structures for oral mucosa tissue engineering applications, non-irradiated and gamma irradiated nonwovens were immersed in three different solutions, in which simulated body fluid (SBF) and artificial saliva are important for future oral mucosa tissue engineering. The nonwovens were immersed for 7, 15 and 30 days in SBF, culture media (DMEM) and artificial saliva at 37 °C. Before immersion in the solutions, the dosage of 15 kGy was applied for sterilization in one assay and compared with non-irradiated samples at the same timepoints. Samples were characterized using different techniques such as scanning electron microscopy (SEM), differential scanning calorimetric (DSC) and gel permeation chromatography (GPC) to evaluate the nonwoven degradation and Fourier-transform infrared spectroscopy (FTIR) to evaluate the chain scissions. Our results showed that PLGA nonwovens were constituted by semicrystalline fibers with moderate degradation properties up to thirty days. The non-irradiated samples exhibited slower kinetics of degradation than irradiated nonwovens. For immersion times longer than 7 days in the three different solutions, the mean diameter of irradiated fibers stayed in the same range, but significantly different from the control sample. On non-irradiated samples, the degradation kinetics was slower and the plateau in the diameter value was only attained after 30 days of immersion in the fluids. Plasticization (fluid absorption into the fiber structure) occurred in the bulk material, as confirmed by a decrease in Tg observed by DSC analyses of non-irradiated and irradiated nonwovens, in comparison with the respective controls. In addition, artificial saliva showed a higher capacity of influencing PLGA crystallization than SBF and DMEM. FTIR analyses showed typical PLGA chemical functional groups changes. These results will be important for future application of those PLGA electrospun nonwovens for oral mucosa regeneration.

Study on the Mechanism of Action of Paclitaxel-Loaded Polylactic-co-glycolic Acid Nanoparticles in Non-Small-Cell Lung Carcinoma Cells

“…Inactive apoptosis of cancer cells results in low mortality of malignant cells [ 30 ]. Many previous studies [ 31 – 34 ] have shown that PTX can induce apoptosis of cancer cells to a certain extent. Yuan et al [ 35 ] also reported that the PTX delivery system based on PLGA-Tween 80 copolymer can significantly induce apoptosis of A549 cells and thus play a therapeutic role in vitro, which is similar to our research results.…”

Bioactive Ibuprofen-Loaded PLGA Coatings for Multifunctional Surface Modification of Medical Devices

“…With an increasing testing time, a diminish in the intensity of carbonyl originating from copolymer’s ester bonds (~1750 cm −1 ) was observed, accompanied by the appearance of a new peak at ~1710 cm −1 . This lower wavenumber band was particularly associated with vibrations of hydrogen-bounded carbonyl from carboxylic acids, such as LA and GA resulted from SBF-mediated hydrolysis of PLGA [ 72 , 73 ]. At the same time, more pronounced maxima and spectral widening occurred in the 3000–2850 cm −1 region, as a result of overlapped –CH and O–H vibrations, also originating from carboxylic acids.…”

Electrospun nanofiber scaffold for vascular tissue engineering

“…In one study, porcine smooth muscle cells grew on PLGA nanofibers for 30 days after which growth slowed [51]. PLGA nanofibers have been shown to shrink in fluids including Dulbecco's Modified Eagle Medium (DMEM), simulated body fluid (SFB), and saliva [52]. This is due to fluid-induced relaxation of the polymer chain and can increase hydrolytic and enzymatic degradation.…”

“…Any implantable medical device also has to undergo sterilization, which has also been shown to speed the degradation of PLGA. Chor et al [52] found that gamma irradiated electrospun PLGA scaffolds had low polymer molecular weight and enhanced hydrolytic degradation in SBF and saliva compared to nonirradiated scaffolds. Since PLGA undergoes bulk erosion, the mechanical properties of PLGA decrease as it degrades and may pose a problem for the long-term patency of a PLGA TEVG, especially, if it degrades before substantial remodeling and integration can occur.…”