Examining the Effects of Thermally-Degraded Nanoclay Enforced Polylactic Acid Composite on Cellular Systems

Polylactic acid (PLA), a naturally hydrophilic polymer, has been widely used in food packaging applications because of its biocompatibility and non-toxic degradation.  However, the mechanical properties of PLA alone when used in such applications can be altered upon environmental exposure. PLA reinforced with nanoclays has been proposed as an alternative to reduce PLA. The nanoclays have been shown to impact the polymer's mechanical properties by improving strength, heat resistance, percolation properties, and increasing its thermal stability. However, before nanocomposites are used in food packaging, the environmental exposure, disposal, and residue impact on biological systems must be assessed. This research focuses primarily on examining the effects of nanoclay-enforced PLA nanocomposite on cellular systems. For these experiments, PLA was mixed with nanoclay and thermally degraded at different conditions. Scanning Electron Microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX), and solubility tests were used to analyze the physical and chemical properties of the nanocomposites upon thermal degradation. The biological effects of nanocomposites and their thermally degraded counter parts were studied in relation to human lung epithelial cells (BEAS-2B). Measuring the cellular viability, proliferation, and changes in cellular morphology at varying time points showed that the thermal degradation of the nanocomposites drastically impacted the cellular systems. This research can provide insights into the biodegradation of nanocomposites and the effects of such degradation on the environment and help establish regulation standards for nanocomposite integration into food packaging applications.