Natural deep eutectic solvent supported targeted solid-liquid polymer carrier for breast cancer therapy

Abstract

Solid-liquid nanocarriers (SLNs) are at the front of the rapidly emerging field of medicinal applications with a potential role in the delivery of bioactive agents. Here, we report a new SLN of natural deep eutectic solvent (NADES) and biotin-conjugated lysine-polyethylene glycol copolymer. The SLN system was analyzed for its functional groups, thermal stability, crystalline nature, particle size, and surface morphology through the instrumental analysis of FT-IR, TGA, XRD, DLS, SEM, and TEM. Encapsulation of PTX (paclitaxel) and 7-HC (7-hydroxycoumarin) with the SLN was carried out by dialysis, and UV-visible spectra evidenced the drug loading capacity and higher encapsulation efficiency obtained. The enhanced anticancer potential of PTX- and 7-HC-loaded SLN was assessed in vitro, and the system reduces the cell viability of MDA-MB-231 cells. The PTX- and 7-HC-loaded SLN system was investigated in a breast cancer-induced rat model via in vivo studies. It shows decreased lysosomal enzymes and increased levels of caspase to cure breast tumors. It very well may be reasoned that the designed PTX- and 7-HC-loaded SLN system has strong anticancer properties and exhibits potential for delivery of drug molecules in cancer treatment.

Scheme 1. Schematic representation of (A) NADES synthesis and (B) synthetic route of the biotin-conjugated solid–liquid polymer.

Fig. 1. FT-IR spectra of (A) prolinebetaine, (B) lactic acid, (C) NADES-1:2, (D) NADES-1:3, (E) biotin, (F) biotin-g-lysine, (G) biotin-g-lysine-co-PEG, and (H) PTX- and 7-HC-loaded NADES-based biotin-conjugated solid–liquid polymer (PTX- and 7-HC-loaded nanocarrier).

Fig. 2. (a) XRD patterns of (A) biotin-conjugated solid–liquid polymer, (B) NADES-based biotin-conjugated solid–liquid polymer, (C) PTX, (D) 7-HC, and (E) PTX- and 7-HC-loaded nanocarrier. (b) Raman spectra of (A) nanocarrier and (B) PTX- and 7-HC-loaded nanocarrier. (c) TGA measurements for (A) nanocarrier and (B) PTX- and 7-HC-loaded nanocarrier. (d) Fluorescence spectra of micelles (A) intensity ratio I₁/I₃ of pyrene as a function of nanocarrier concentration, and (B) the CMC in an aqueous medium is determined to be about 0.6 mg mL⁻¹.

Fig. 3. (a) SEM images of (A) nanocarrier and (B) PTX- and 7-HC-loaded nanocarrier. TEM images of (C) nanocarrier and (D) PTX- and 7-HC-loaded nanocarrier. The blue arrow indicates the hydrophilic outer layer, and the yellow arrow indicates the hydrophobic inner layer. (b) Zeta potential of (A) nanocarrier and (B) PTX- and 7-HC-loaded nanocarrier, and particle size of (C) nanocarrier and (D) PTX- and 7-HC-loaded nanocarrier.

Fig. 4. UV-visible spectroscopy showing (A) encapsulation efficiency and (B) percentage encapsulation efficiency of PTX- and 7-HC-loaded nanocarrier. In vitro drug discharge status of PTX- and 7-HC-loaded nanocarrier at (C) pH 2.8, (D) pH 5.5, and (E) pH 7.4. (F) Cumulative drug release pattern over 320 min.

Fig. 5. (A) The cell viability of PTX- and 7-HC-loaded SLN-treated normal cell line. (B) The cytotoxicity of PTX- and 7-HC-loaded SLN against MDA-MB-231 cancer cell line.

Fig. 6. Confocal images of MDA-MB-231 cancer cells incubated with PTX- and 7-HC-loaded SLN system at 27 °C for (A) 1 h, (B) 5 h, (C) 10 h, (D) 15 h, (E) 20 h, and (F) 24 h. White arrows indicate the presence of PTX- and 7-HC-loaded SLN around nuclei.

Fig. 7. (B and C) Effect of PTX- and 7-HC-loaded nanocarrier on lysosomal marker enzymes. Group I, control; group II, cancer induced; group III, SLN unloaded treated; group IV, SLN loaded treated. Each value is expressed as the mean ± SD for six rats in each group. Significance compared to group I is shown as *P < 0.05. (A) Effect of PTX- and 7-HC-loaded nanocarrier on caspase-3, -8, and -9. Group I, control; group II, cancer induced; group III, SLN unloaded treated; group IV, SLN loaded treated. Each value is expressed as the mean ± SD for six rats in each group. Significant difference as compared to group I shown as *P < 0.05.

Fig. 8. Histological sections of mammary tissue of DMBA-induced breast cancer in rats from (A) control, (B) cancer induced, (C) SLN unloaded treated, and (D) SLN loaded treated. Liver sections of DMBA-induced breast cancer in rats from (E) control, (F) cancer induced, (G) SLN unloaded treated, and (H) SLN loaded treated.