Preparation of Magnetic-Luminescent Bifunctional Rapeseed Pod-Like Drug Delivery System for Sequential Release of Dual Drugs

Abstract

Drug delivery systems (DDSs) limited to a single function or single-drug loading are struggling to meet the requirements of clinical medical applications. It is of great significance to fabricate DDSs with multiple functions such as magnetic targeting or fluorescent labeling, as well as with multiple-drug loading for enhancing drug efficacy and accelerating actions. In this study, inspired by the dual-chamber structure of rapeseed pods, biomimetic magnetic-luminescent bifunctional drug delivery carriers (DDCs) of 1.9 ± 0.3 μm diameter and 19.6 ± 4.4 μm length for dual drug release were fabricated via double-needle electrospraying. Morphological images showed that the rapeseed pod-like DDCs had a rod-like morphology and Janus dual-chamber structure. Magnetic nanoparticles and luminescent materials were elaborately designed to be dispersed in two different chambers to endow the DDCs with excellent magnetic and luminescent properties. Synchronously, the Janus structure of DDCs promoted the luminescent intensity by at least threefold compared to single-chamber DDCs. The results of the hemolysis experiment and cytotoxicity assay suggested the great blood and cell compatibilities of DDCs. Further inspired by the core-shell structure of rapeseeds containing oil wrapped in rapeseed pods, DDCs were fabricated to carry benzimidazole molecules and doxorubicin@chitosan nanoparticles in different chambers, realizing the sequential release of benzimidazole within 12 h and of doxorubicin from day 3 to day 18. These rapeseed pod-like DDSs with excellent magnetic and luminescent properties and sequential release of dual drugs have potential for biomedical applications such as targeted drug delivery, bioimaging, and sustained treatment of diseases.

Keywords: dual drugs; electrospray; magnetic–luminescent bifunctional drug delivery carrier; rapeseed pod-like drug delivery system; sequential release.

Figure 1

(A) Schematic diagram of the process of preparing magnetic–luminescent bifunctional rapeseed pod-like D2 DDCs: (i) schematic diagram of the preparation of CS NPs via electrospraying; (ii) schematic diagram of preparing D2 DDCs by double-needle electrospraying. (B) Schematic diagram of the process of preparing magnetic–luminescent bifunctional rapeseed pod-like R2 DDSs for the sequential release of dual drugs.

Figure 2

(A) TEM image and diameter distribution of Fe₃O₄ MNPs; more than 450 Fe₃O₄ MNPs were measured. (B) Hysteresis loop and magnetic responsiveness testing photographs of Fe₃O₄ MNPs. (C) TEM image and diameter distribution of NaYF₄:Eu³⁺ NPs; more than 350 NaYF₄:Eu³⁺ NPs were measured. (D) Fluorescent microscope image and emission spectra of NaYF₄:Eu³⁺ NPs. (E) SEM image and diameter distribution of CS NPs; more than 400 CS NPs were measured. (F) Zeta potentials of Fe₃O₄ MNPs, NaYF₄:Eu³⁺ NPs, and CS NPs.

Figure 3

(A) SEM images of S1, D1, S2, and D2 DDCs. (B) Average lengths and diameters of S1, D1, S2, and D2 DDCs, showing a significant difference in length (*** p < 0.001) and in diameter (^### p < 0.001). (C) Ratios of length to diameter of S1, D1, S2, and D2 DDCs; at least 400 of DDCs were observed to measure the length, diameter, and aspect ratio, using the software Image J 1.48v.

Figure 4

(A) FTIR spectra of CS, PLGA, and D2 DDCs. (B) Contact angles of CS NPs and D1 and D2 DDCs, and the corresponding images of water droplets on different samples, *** p < 0.001. (C) XRD patterns of Fe₃O₄ MNPs, NaYF₄:Eu³⁺ NPs, and D2 DDCs. (D) Optical microscope image of D2 DDC. (E) Hysteresis loops of S2 and D2 DDCs. (F) Emission spectra of S2 and D2 DDCs. (G) Fluorescent microscope images of S2 and D2 DDCs.

Figure 5

(A) Hemolysis rate and photographs of D2 DDCs at concentrations ranging from 3.125 to 800 μg/mL. (B) In vitro cell viabilities of A549 cells and HUVECs normalized to the untreated control after incubation with D2 DDCs for 24 h at concentrations of 3.125–800 μg/mL. (C) Optical microscope images of A549 cells incubated with the D2 DDCs under the effect of a magnet: (i) without magnet; (ii) far from the magnet; (iii) near the magnet. (D) Fluorescent microscope images of A549 cells incubated with D2 DDCs: (i) bright-field image; (ii) fluorescent image; (iii) overlay of the bright-field and fluorescent images.

Figure 6

(A) Bim and DOX encapsulation efficiencies of R1 and R2 DDSs. Percentage of Bim and DOX released from R1 DDSs within (B) 35 days and (C) 48 h. Percentage of Bim and DOX released from R2 DDSs within (D) 35 days and (E) 336 h. (F) Release difference of DOX in R1 and R2 DDSs measured at every two detection time points: measured value (inset) and Gauss fitted value.

Figure 7

(A) In vitro A549 cell relative viabilities normalized to the untreated control after incubation for 48 h with different concentrations of R2 DDSs; * p < 0.05, ** p < 0.01, *** p < 0.001. (B) In vitro A549 cell relative viabilities normalized to the untreated control for 28 days with D2 DDCs, R1 and R2 DDSs, and drugs of Bim and DOX. (C) Schematic illustration of the release of two model drugs (Bim and DOX) from R2 DDSs: (i) R2 with Bim in left chamber and DOX@CS NPs in right chamber before drug release; (ii) Bim and partial DOX released within 12 h; (iii) the suspended release of DOX within ~3 to 18 days.