Actively-targeted LTVSPWY peptide-modified magnetic nanoparticles for tumor imaging

Figures & data

Figure 1 Synthetic scheme of LTVSPWY-PEG-CS.

Abbreviations: PEG, poly(ethylene glycol); CS, chitosan.

Figure 2 ¹H NMR spectra of LTVSPWY-PEG-CS (A), peptide LTVSPWY (B), CS (C) and NH₂-PEG-NH₂ (D). The important peaks are pointed out.

Abbreviations: PEG, poly(ethylene glycol); CS, chitosan.

Table 1 Size and zeta potential of magnetic nanoparticles

Sample	Dn (nm)	PI (−)	Zeta potential (mV)
Non-modified MNPs	156.0 ± 11.5	0.19 ± 0.03	−10.4 ± 3.5
LTVSPWY-PEG-CS modified MNPs	267.3 ± 23.4	0.55 ± 0.14	30.5 ± 7.0
PEG-CS-modified MNPs	275.0 ± 59.4	0.48 ± 0.11	22.1 ± 0.8
CS-modified MNPs	278.3 ± 15.6	0.40 ± 0.09	23.1 ± 1.9

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

Abbreviations: MNPs, magnetic nanoparticles; PI, polydispersity index; dn, average diameter of magnetic nanoparticles; PEG, poly(ethylene glycol); CS, chitosan.

Figure 3 Characteristics of magnetic nanoparticles. Size distribution (A) and zeta potential (B) of LTVSPWY-PEG-CS-modified magnetic nanoparticles obtained by dynamic light scattering.

Abbreviations: PEG, poly(ethylene glycol); CS, chitosan.

Figure 4 Transmission electron microscopic images of magnetic nanoparticles. (A) LTVSPWY-PEG-CS-modified magnetic nanoparticles, (B) PEG-CS-modified magnetic nanoparticles, and (C) CS-modified magnetic nanoparticles.

Note: The bar is 50 nm.

Abbreviations: PEG, poly(ethylene glycol); CS, chitosan.

Figure 5 Cytotoxicity of magnetic nanoparticles against A549 (A) and SKOV-3 (B) cells. The magnetic nanoparticles prepared consisted of 50 μg/mL Fe₃O₄, 50 μg/mL oleic acid, 350 μg/mL monostearin, and 50 μg/mL chitosan.

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

Abbreviations: PEG, poly(ethylene glycol); CS, chitosan.

Figure 6 Fluorescence images of competitive cellular uptake of RITC-labeled magnetic nanoparticles for 12 hours. A549 cells (HER2-negative, cytoplasmic membrane-labeled with PKH67 fluorescent linker, green) cocultured with HER2-overexpressing SKOV-3 cells were incubated with RITC-labeled magnetic nanoparticles (red). (A) LTVSPWY-PEG-CS-modified magnetic nanoparticles, (B) PEG-CS-modified magnetic nanoparticles, and (C) chitosan-modified magnetic nanoparticles.

Note: The cells were all stained with Hoechst 33342.

Abbreviations: RITC, rhodamine B isothiocyanate; PEG, poly(ethylene glycol); CS, chitosan.

Figure 7 In vivo and ex vivo biodistribution of DiR-loaded magnetic nanoparticles after intravenous tail injection in tumor-bearing nude mice. The fluorescent images of in vivo tumor-bearing nude mice (A–B) and ex vivo image of major organs (A′–C′) using DiR probes with three different magnetic nanoparticles, ie, (A and A′) LTVSPWY-PEG-CS-modified magnetic nanoparticles, (B and B′) PEG-CS-modified magnetic nanoparticles, and (C and C′) chitosan-modified magnetic nanoparticles.

Notes: The images were spectrally resolved. The tumor area is emphasized by a red arrow.

Abbreviations: PEG, poly(ethylene glycol); CS, chitosan. for the development of novel molecular imaging probes in the early detection and diagnosis of cancer.