RGD peptide-mediated chitosan-based polymeric micelles targeting delivery for integrin-overexpressing tumor cells

Figures & data

Figure 1 Synthetic scheme of RGD-PEG-CS-SA copolymer.

Abbreviations: RGD, Arg-Gly-Asp; PEG, poly(ethylene glycol); SA, stearic acid; CS, chitosan; DSC, N,N′-Disuccinimidyl carbonate; HCl, hydrochloric acid.

Figure 2 Characteristics of copolymers and blank micelles. (A) Change of fluorescence intensity ratio (I₃₇₄/I₃₈₅) for pyrene in distilled water versus the logarithm of concentration of copolymers. The unit of concentration was μg/mL. Poly(ethylene glycol)-modified stearic acid-grafted chitosan (PEG-CS-SA) (Δ); RGD-PEG-CS-SA (□). (B) Size distribution of blank RGD-PEG-CS-SA and (C) DOX-loaded RGD-PEG-CS-SA micelles obtained by DLS.

Abbreviations: DLS, dynamic light scattering; RGD, Arg-Gly-Asp.

Table 1 Size and zeta potential of blank and DOX-loaded micelles with 1 mg/mL concentration

Sample	Size (nm)	PI (−)	Zeta potential (mV)
PEG-CS-SA	39.1 ± 1.8	0.52 ± 0.23	29.6 ± 2.5
RGD-PEG-CS-SA	32.4 ± 3.3	0.55 ± 0.14	31.5 ± 2.1
PEG-CS-SA/DOX	21.5 ± 1.0	0.48 ± 0.11	26.0 ± 0.8
RGD-PEG-CS-SA/DOX	24.8 ± 0.6	0.40 ± 0.09	22.7 ± 2.9

Note: PI represents the polydispersity index of the micelle size. Data represent the mean ± standard deviation (n = 3).

Abbreviations: DOX, doxorubicin; PEG-CS-SA, poly(ethylene glycol)-modified stearic acid-grafted chitosan; RGD, Arg-Gly-Asp.

Table 2 Drug-loading capacity and encapsulation efficiency of PEG-CS-SA and RGD-PEG-CS-SA micelles loading DOX

Sample	Drug loading capacity (%)	Encapsulation efficiency (%)
PEG-CS-SA/DOX	4.9 ± 0.3	95.8 ± 3.4
RGD-PEG-CS-SA/DOX	4.6 ± 0.5	93.2 ± 3.3

Note: Data represent the mean ± standard deviation (n = 3).

Abbreviations: DOX, doxorubicin; PEG-CS-SA, poly(ethylene glycol)-modified stearic acid-grafted chitosan; RGD, Arg-Gly-Asp.

Figure 3 In vitro doxorubicin (DOX)-release profiles from poly(ethylene glycol)-modified stearic acid-grafted chitosan (PEG-CS-SA)/DOX (⋄) and RGD-PEG-CS-SA/DOX (Δ) micelles using pH 7.4 phosphate-buffered saline.

Note: Data represent the mean ± standard deviation (n = 3).

Abbreviation: RGD, Arg-Gly-Asp.

Figure 4 Cytotoxicity of DOX · HCl, poly(ethylene glycol)-modified stearic acid-grafted chitosan (PEG-CS-SA)/DOX and RGD-PEG-CS-SA/DOX toward (A) human hepatocellular carcinoma cell line cells and (B) human epithelial carcinoma cell line cells.

Note: Data represent the mean ± standard deviation (n = 3).

Abbreviations: DOX, doxorubicin; HCl, hydrochloric acid; RGD, Arg-Gly-Asp.

Figure 5 Fluorescence images of doxorubicin (DOX) after (A) human hepatocellular carcinoma cell line cells and (B) human epithelial carcinoma cell line cells were incubated with free DOX, poly(ethylene glycol)-modified stearic acid-grafted chitosan (PEG-CS-SA)/DOX and RGD-PEG-CS-SA/DOX micelles for 2 hours, 8 hours, and 24 hours, respectively.

Abbreviation: RGD, Arg-Gly-Asp.

Figure 6 Cellular uptake percentage of free DOX, DOX-loaded micelles in (A) human hepatocellular carcinoma cell line cells and (B) human epithelial carcinoma cell line cells against incubation time.

Notes: Data represent the mean ± standard deviation (n = 3). *P > 0.05 and **P < 0.01.

Abbreviations: DOX, doxorubicin; PEG-CS-SA, poly(ethylene glycol)-modified stearic acid-grafted chitosan; RGD, Arg-Gly-Asp.