Essential oil-loaded lipid nanoparticles for wound healing

Figures & data

Table 1 Quali-quantitative compositions of all the systems prepared

	Lecithin (mg)	Cocoa butter (mg)	Olive oil (mg)	Sesame oil (mg)	Eucalyptus oil (mg)	Rosemary oil (mg)
SLN b	150	225	–	–	–	–
SLN e	150	225	–	–	75	–
SLN r	150	225	–	–	–	75
NLC o/b	150	150	75	–	–	–
NLC s/b	150	150	–	75	–	–
NLC o/e	150	150	75	–	75	–
NLC o/r	150	150	75	–	–	75
NLC s/b	150	150	–	75	–	–
NLC s/e	150	150	–	75	75	–
NLC s/r	150	150	–	75	–	75

Abbreviations: SLN, solid lipid nanoparticles; NLC, nanostructured lipid carriers; b, blank-unloaded; e, eucalyptus oil; r, rosemary oil; o, olive oil; s, sesame oil.

Figure 1 PS and PI as a function of storage time (2°C–8°C).

Notes: SLN and NLC prepared by using both eucalyptus oil or rosemary oil and (A) olive oil or (B) sesame oil as liquid lipids (mean value ± SD; n=6).

Abbreviations: SLN, solid lipid nanoparticles; NLC, nanostructured lipid carriers; b, blank-unloaded; e, eucalyptus oil; r, rosemary oil; o, olive oil; s, sesame oil; PI, polydispersity index; PS, particle size.

Figure 2 Bioadhesion parameter (normalized work of adhesion [ΔAUC/AUC]) of all the nanosystem suspensions and nanosystem suspensions containing 5% w/w pullulan (pull) (mean value ± SD; n=6).

Abbreviations: SLN, solid lipid nanoparticles; NLC, nanostructured lipid carriers; e, eucalyptus oil; r, rosemary oil; o, olive oil; s, sesame oil.

Figure 3 Cytocompatibility (viability %) of fibroblasts with all the nanoparticle suspensions, loaded with eucalyptus or rosemary oils (1/20, 1/40, and 1/100). Notes: Nanoparticle suspensions containing 5% w/w pullulan were also tested at 1/100 dilution. GM was used as comparison (positive control) (mean value ± SD; n=8).

Abbreviations: e, eucalyptus oil; GM, growth medium; NLC, nanostructured lipid carriers; o, olive oil; r, rosemary oil; s, sesame oil; SLN, solid lipid nanoparticles.

Figure 4 Proliferation (% viability) for all the nanosystems developed loaded with eucalyptus or rosemary oils.

Notes: Nanoparticle suspensions and nanoparticle suspensions containing 5% w/w pullulan at 1/100 dilution were tested. GM was used as comparison (positive control) (mean value ± SD; n=8).

Abbreviations: GM, growth medium; SLN, solid lipid nanoparticles; NLC, nano-structured lipid carriers; e, eucalyptus oil; r, rosemary oil; o, olive oil; s, sesame oil.

Figure 5 Microphotographs of cell substrates taken at time 0 (immediately after insert removal) and after 48 h of growth, by using optical microscope and after 48 h of growth by using fluorescence microscope (cell nuclei stained with Hoechst 33258 in blue and proliferating cells stained with anti-BrdU antibody in green). Scale bars =200 µm.

Abbreviations: GM, growth medium; SLN, solid lipid nanoparticles; NLC, nanostructured lipid carriers; e, eucalyptus oil; r, rosemary oil; o, olive oil; s, sesame oil.

Figure 6 Transmission electron microscope microphotograph of NLC o/e.

Abbreviations: NLC, nanostructured lipid carriers; e, eucalyptus oil; o, olive oil.

Table 2 MIC values against Staphylococcus aureus and Streptococcus pyogenes for eucalyptus essential oil and NLC o/e

	Strain	MIC (mg/mL)
Eucalyptus oil	Staphylococcus aureus ATCC 6538	3
	Streptococcus pyogenes ATCC 19615	1.5
NLC o/e	Staphylococcus aureus ATCC 6538	3
	Streptococcus pyogenes ATCC 19615	0.75

Abbreviations: ATCC, American Type Culture Collection; MIC, minimum inhibitory concentration; NLC, nanostructured lipid carriers; e, eucalyptus oil; o, olive oil.

Figure 7 Profiles of wound area (cm²) vs time profiles of wounds treated with NLC o/e suspension and NLC o/e suspension containing 5% w/w pullulan and saline solution (control) (mean value ± SD; n=3). *p<0.05, one-way ANOVA, multiple range test.

Abbreviations: NLC, nanostructured lipid carriers; e, eucalyptus oil; o, olive oil.

Figure 8 Microphotographs of skin sections stained with hematoxylin and eosin, taken from the wounded area at 18th day of treatment with saline solution, as negative control (A), nanostructured lipid carriers (NLC) o/e suspension (B), and NLC o/e suspension containing 5% w/w pullulan (C) in comparison with intact skin (D) (scale bar: 200 µm).

Notes: Asterisk: necrotic tissue; arrow: granulation tissue; black star: vacuoles/blood vessels; white star: dermal papillae; white arrow: bundles of collagen; white triangle: dermal appendages.

Abbreviations: NLC, nanostructured lipid carriers; e, eucalyptus oil; o, olive oil.