Development of novel cationic chitosan-and anionic alginate–coated poly(d,l-lactide-co-glycolide) nanoparticles for controlled release and light protection of resveratrol

Figures & data

Figure 1 Chemical structure of RSV, PLGA, CS, and Alg, and schematic representation of the nanoprototypes.

Abbreviations: RSV, trans-(E)-resveratrol; PLGA, poly(d,l-lactide-co-glycolide); CS, chitosan; Alg, alginate.

Table 1 Theoretical composition of RSV-loaded NPs

Formulation	PLGA	CS	Alg	RSV
PLGA	100	–	–	1
PLGA-CS1	100	5.0	–	1
PLGA-CS2	100	12.5	–	1
PLGA-CS3	100	25.0	–	1
PLGA-Alg1	100	–	5.0	1
PLGA-Alg2	100	–	12.5	1
PLGA-Alg3	100	–	25.0	1

Notes: Composition expressed in milligrams (mg); PLGA, PLGA-CS1-3 and PLGA-Alg1-3 indicate RSV-loaded NPs.

Abbreviations: CS, chitosan; Alg, alginate; RSV, trans-resveratrol; PLGA, poly(d,l-lactide- co-glycolide); NPs, nanoparticles.

Figure 2 SEM images of PLGA (A), PLGA-CS1 (B), PLGA-CS2 (C), PLGA-CS3 (D), PLGA-Alg1 (E), PLGA-Alg2 (F), and PLGA-Alg3 (G) RSV-loaded NPs.

Abbreviations: RSV, trans-(E)-resveratrol; PLGA, poly(d,l-lactide-co-glycolide; NPs, nanoparticles.

Figure 3 Mean diameter (A) and zeta potential (B) of uncoated PLGA NPs (PLGA) and NPs coated with different amounts (5.0, 12.5, and 25.0 mg) of CS and Alg.

Notes: *Significantly different from the PLGA; ^#significantly different from other CS-coated NPs.

Abbreviations: PLGA, poly(d,l-lactide-co-glycolide; NPs, nanoparticles.

Figure 4 RSV loading content (A) and encapsulation efficiencies (B) of uncoated PLGA NPs and nanosystems coated with different amounts (5.0, 12.5, and 25.0 mg) of CS and Alg.

Notes: *Significantly different from the PLGA; ^#significantly different from other CS-coated NPs; ^§significantly different from other Alg coated-NPs.

Abbreviations: RSV, trans-(E)-resveratrol; PLGA, poly(d,l-lactide-co-glycolide); CS, chitosan; Alg, alginate; NPs, nanoparticles.

Figure 5 (A) Raman spectra of RSV, PLGA, CS, and Alg (raw materials); (B) PLGA, PLGA-CS3, and PLGA-Alg3 RSV loaded NPs.

Abbreviations: RSV, trans-(E)-resveratrol; PLGA, poly(d,l-lactide-co-glycolide); CS, chitosan; Alg, alginate; NPs, nanoparticles.

Figure 6 DSC curves of (A) pure CS and Alg, (B) pure RSV and PLGA, (C) uncoated PLGA, PLGA-CS3, and PLGA-Alg3 NPs, and (D) physical mixture of PLGA/RSV, PLGA/CS/RSV and PLGA/Alg/RSV.

Abbreviations: RSV, trans-(E)-resveratrol; PLGA, poly(d,l-lactide-co-glycolide); CS, chitosan; Alg, alginate; NPs, nanoparticles.

Figure 7 (A and B) Swelling index of different NPs as a function of time in PBS solution (pH 7.4, 37°C).

Abbreviations: PLGA, poly(d,l-lactide-co-glycolide); NPs, nanoparticles; PBS, phosphate-buiffered saline.

Figure 8 (A and B) In vitro release profiles (PBS, pH 7.4, 37°C) of RSV from NPs.

Abbreviations: RSV, trans-(E)-resveratrol; PLGA, poly(d,l-lactide-co-glycolide); PBS, phosphate-buffered saline.

Table 2 Coefficient of determination (R²) and release exponent (n) of kinetic data analysis of RSV release from different polymeric nanoparticles

Formulation	Zero-order	First-order	Higuchi	Korsmeyer–Peppas
	R^2	R^2	R^2	R^2	n
PLGA	0.9329	0.7643	0.9616	0.9635	0.111
PLGA-CS1	0.8062	0.9452	0.9071	0.9605	0.297
PLGA-CS2	0.8544	0.9515	0.9420	0.9582	0.422
PLGA-CS3	0.8826	0.9542	0.9533	0.9625	0.336
PLGA-Alg1	0.6973	0.8475	0.7991	0.8635	0.129
PLGA-Alg2	0.7596	0.8931	0.8480	0.8966	0.143
PLGA-Alg3	0.9368	0.9791	0.9827	0.9909	0.320

Note: PLGA, PLGA-CS1-3, and PLGA-Alg1-3 indicate RSV-loaded NPs.

Abbreviations: PLGA, poly(d,l-lactide-co-glycolide); CS, chitosan; Alg, alginate; RSV, trans-resveratrol; NPs, nanoparticles.

Figure 9 The retention percentage of unencapsulated RSV and uncoated PLGA, PLGA-CS1, PLGA-CS3, PLGA-Alg1, and PLGA-Alg3 NPs exposed to UV lamp for 120 minutes.

Notes: *Significantly different from the free RSV; ^#significantly different from PLGA; ^§significantly different from other CS-coated NPs; °significantly different from other Alg-coated NPs.

Abbreviations: RSV, trans-(E)-resveratrol; PLGA, poly(d,l-lactide-co-glycolide); CS, chitosan; Alg, alginate, NPs, nanoparticles.

Figure 10 RSV loading content of uncoated PLGA NPs and nanosystems coated with different amounts (5.0, 12.5, and 25.0 mg) of CS and Alg after 6 months of storage at 4°C.

Notes: *Significantly different from PLGA; ^#significantly different from other CS-coated NPs; ^§significantly different from other Alg-coated NPs.

Abbreviations: RSV, trans-(E)-resveratrol; PLGA, poly(d,l-lactide-co-glycolide); CS, chitosan; Alg, alginate; NPs, nanoparticles.

Figure 11 (A) HPLC chromatograms of RSV (trans-resveratrol) before (a) and after exposure to UV for 30 minutes (b) and 120 minutes (c). (B) UV-Vis spectra of trans- and cis-resveratrol conversion induced by UV exposure.

Abbreviations: HPLC, high-performance liquid chromatography; UV-Vis, UV visible.