Synthesis of D-Limonene Loaded Polymeric Nanoparticles with Enhanced Antimicrobial Properties for Potential Application in Food Packaging

Abstract

Mini-emulsion polymerization was applied for the synthesis of cross-linked polymeric nanoparticles comprised of methyl methacrylate (MMA) and Triethylene Glycol Dimethacrylate (TEGDMA) copolymers, used as matrix-carriers for hosting D-limonene. D-limonene was selected as a model essential oil, well known for its pleasant odor and its enhanced antimicrobial properties. The synthesized particles were assessed for their morphology and geometric characteristics by Dynamic Light Scattering (DLS) and Scanning Electron Microscopy (SEM), which revealed the formation of particles with mean diameters at the nanoscale (D[3,2] = 0.135 μm), with a spherical shape, while the dried particles formed larger clusters of several microns (D[3,2] = 80.69 μm). The percentage of the loaded D-limonene was quantified by Thermogravimetric Analysis (TGA), complemented by Gas Chromatography-Mass Spectrometry analysis coupled with a pyrolysis unit (Py/GC-MS). The results showed that the volatiles emitted by the nanoparticles were composed mainly of D-limonene (10% w/w of dry particles). Particles subjected to higher temperatures tended to decompose. The mechanism that governs the release of D-limonene from the as-synthesized particles was studied by fitting mathematical models to the release data obtained by isothermal TGA analysis of the dry particles subjected to accelerated conditions. The analysis revealed a two-stage release of the volatiles, one governed by D-limonene release and the other governed by TEGDMA release. Finally, the antimicrobial potency of the D-limonene-loaded particles was demonstrated, indicating the successful synthesis of polymeric nanoparticles loaded with D-limonene, owing to enhanced antimicrobial properties. The overall performance of these nanoparticles renders them a promising candidate material for the formation of self-sterilized surfaces with enhanced antimicrobial activity and potential application in food packaging.

Development of Bio-Composites with Enhanced Antioxidant Activity Based on Poly(lactic acid) with Thymol, Carvacrol, Limonene, or Cinnamaldehyde for Active Food Packaging

“…As it is clear fitting is very good in most temperatures for both thymol and carvacrol release, whereas differences appear mainly at large release times. A similar good fit of experimental data using an equation similar to Equation (10) was also observed during the release of limonene [60].…”

“…Recently, the synthesis of d-limonene-loaded polymeric nanoparticles with enhanced antimicrobial properties [60] and the effect of montmorillonite/essential oil nanohybrids on the kinetics of the in situ radical polymerization of styrene [61] were also investigated by our laboratory.…”

“…Equation ( 8) is much more difficult to solve and depends on the particular form providing the dependence of D on the concentration. Since this dependence is not known for a variety of systems, we preferred here to follow an approach also followed in a recent publication from our group, on the release of limonene from PMMA particles [60]. Accordingly, a two-component model was used to model the desorption of the active compound from the polymer sample.…”

“…Thus, to take into account the dependence of D on concentration, two diffusion processes are considered to occur, a fast and a slow one characterized by a high and a low diffusion coefficient, respectively. Then, the total model equation comprising both the fast and the slow diffusivity of the desorbing active compound is given by [60].…”

Poly (lactic acid)/D‐limonene/ZnO bio‐nanocompositeswith antimicrobial properties

“…T A B L E 2 Results of the thermal properties for neat PLA, PLA/D-limonene, and nanocomposites. Standard deviation between 1 and 2% was omitted for the sake of clarity The presence of D-limonene was discerned through a broad peak in the range between 125 and 200 C. 63 However, the peak revealed a nonsignificant contribution to the main thermal decomposition process, as shown by T 10 values similar to those of pure PLA. However, T 10 and T max decreased due to the incorporation of ZnO by 33% and 31%, respectively.…”