The value of fluorescent imaging by c(RGDyk) modified liposome encapsulating quantum dots in the accurate delineation of glioma margin for the precise surgical resection of tumor
1.School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China; 2.Department of Orthopedics,the First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325015, China
WU Zhaohang,DONG Weijie,XUE Pengpeng, et al. The value of fluorescent imaging by c(RGDyk) modified liposome encapsulating quantum dots in the accurate delineation of glioma margin for the precise surgical resection of tumor[J]. JOURNAL OF WEZHOU MEDICAL UNIVERSITY, 2020, 50(10): 782-788.
Abstract：Objective: To prepare c(RGDyk) cyclic peptide modified liposome encapsulating quantumdots (QDs) and evaluate its ability to delineate accurately glioma margin by fluorescent imaging for the accurate urgical resection of tumor. Methods: The mixed lipid materials including hydrogenated soybean phospholipid/distearoyl phosphoethanolamine-PEG2000/cholesterol were used to encapsulate ZnCdSe/ZnS quantum dots(QDs) to prepare QDs-liposome (QDs-Lip) through the reverse evaporation method. Afterwards, c(RGDyk) cyclic peptide as a targeting ligand was conjugated to the amino group on the surface of QDs-Lip by EDC/NHS
condensation reaction to obtain QDs-c(RGDyk)-Lip. Dynamic light scatting (DLS) and Transmission electron microscope (TEM) were used to characterize particle size and morphology of QDs-c(RGDyk)-Lip in vitro.Meanwhile, the stability of QDs-c(RGDyk)-Lip in physiologic relevant medium was also evaluated in terms of both fluorescent emission spectrum and particle size. In vitro CCK-8 assay was used to evaluate the toxic effect of QDs-c(RGDyk)-Lip on PC12 cells and C6 cells. Besides, the cellular uptake of QDs-c(RGDyk)-Lip by C6 cells was evaluated by laser scanning confocal microscopy in presence of free c(RGDyk) or not. Upon intravenous
injection of QDs-c(RGDyk)-Lip, fluorescent imaging of brain of glioma-bearing rats was collected to evaluate its ability to accurately delineate the margin between tumor tissue and normal tissue and the accurate surgical resection of tumor was confirmed by HE staining. Results: The successful encapsulation of QDs was confirmed
by TEM and DLS. The particle size of free QDs was about 35nm, but the particle size of QDs-c(RGDyk)-Lip increased to 175 nm with narrow particle distribution (PDI=0.12). Moreover, QDs-c(RGDyk)-Lip displayed the vesicle-like morphology with small aggregate of QDs in center. QDs-c(RGDyk)-Lip exhibited the maximum
peak at 610 nm by the fluorescent emission spectrum. The good stability of QDs-c(RGDyk)-Lip in in physiologic relevant medium was confirmed by both fluorescent emission spectrum and particle size. In vitro cytotoxicity study showed that QDs-c(RGDyk)-Lip had the weak toxicity toward PC12 or C6 cells only at high concentration.
QDs-c(RGDyk)-Lip was effectively up-taken by C6 cells, resulting in the strong fluorescence in their cytoplasm.Moreover, the fluorescence of QDs-c(RGDyk)-Lip in C6 cells was obviously inhibited by pre-incubating with free c(RGDyk), indicating that its specific targeting toward C6 cells. Animal experiments show that QDsc(
RGDyk)-Lip can effectively target the glioma-bearing rats after intravenous injection for the accurate surgical resection of tumor. Conclusion: c(RGDyk) cyclic peptide modified liposome in combination with quantum dots constructs QDs-c(RGDyk)-Lip as a safe and stable fluorescent probe, which can specifically target glioma tissue
and accurately guide surgical resection.
