Synthesis and in vitro experiments of carcinoma vascular endothelial targeting polymeric nano-micelles combining small particle size and supermagnetic sensitivity.

Objective: To construct carcinoma vascular endothelial-targeted polymeric nanomicelles with high magnetic resonance imaging (MRI) sensitivity and to evaluate their biological safety and in vitro tumor-targeting effect, and to monitor their feasibility using clinical MRI scanner. Method: Amphiphilic block copolymer, poly(ethylene glycol)-b-poly(ε-caprolactone) (PEG-PCL) was synthesized via the ring-opening polymerization of ε-caprolactone (CL) initiated by poly(ethylene glycol) (PEG), in which cyclic pentapeptide Arg-Gly-Asp (cRGD) was conjugated with the terminal of hydrophilic PEG block. During the self-assembly of PEG-PCL micelles, superparamagnetic γ-Fe2O3 nanoparticles (11 nm) was loaded into the hydrophobic core. The cRGD-terminated γ-Fe2O3-loaded polymeric micelles targeting to carcinoma vascular endothelial cells, were characterized in particle size, morphology, loading efficiency and so on, especially high MRI sensitivity in vitro. Normal hepatic vascular endothelial cells (ED25) were incubated with the resulting micelles for assessing their safety. Human hepatic carcinoma vascular endothelial cells (T3A) were cultured with the resulting micelles to assess the micelle uptake using Prussian blue staining and the cell signal intensity using MRI. Results: All the polymeric micelles exhibited ultra-small particle sizes with approximately 50 nm, high relaxation rate, and low toxicity even at high iron concentrations. More blue-stained iron particles were present in the targeting group than the non-targeting and competitive inhibition groups. In vitro MRI showed T2WI and T2 relaxation times were significantly lower in the targeting group than in the other two groups. Conclusion: γ-Fe2O3-loaded PEG-PCL micelles not only possess ultra-small size and high superparamagnetic sensitivity, also can be actively targeted to carcinoma vascular endothelial cells by tumor-targeted cRGD. It appears to be a promising contrast agent for tumor-targeted imaging.

Preliminary Study of MR and Fluorescence Dual-mode Imaging: Combined Macrophage-Targeted and Superparamagnetic Polymeric Micelles.

Purpose: To establish small-sized superparamagnetic polymeric micelles for magnetic resonance and fluorescent dual-modal imaging, we investigated the feasibility of MR imaging (MRI) and macrophage-targeted in vitro. Methods: A new class of superparamagnetic iron oxide nanoparticles (SPIONs) and Nile red-co-loaded mPEG-Lys3-CA4-NR/SPION polymeric micelles was synthesized to label Raw264.7 cells. The physical characteristics of the polymeric micelles were assessed, the T2 relaxation rate was calculated, and the effect of labeling on the cell viability and cytotoxicity was also determined in vitro. In addition, further evaluation of the application potential of the micelles was conducted via in vitro MRI. Results: The diameter of the mPEG-Lys3-CA4-NR/SPION polymeric micelles was 33.8 ± 5.8 nm on average. Compared with the hydrophilic SPIO, mPEG-Lys3-CA4-NR/SPION micelles increased transversely (r2), leading to a notably high r2 from 1.908 µg/mL-1S-1 up to 5.032 µg/mL-1S-1, making the mPEG-Lys3-CA4-NR/SPION micelles a highly sensitive MRI T2 contrast agent, as further demonstrated by in vitro MRI. The results of Confocal Laser Scanning Microscopy (CLSM) and Prussian blue staining of Raw264.7 after incubation with micelle-containing medium indicated that the cellular uptake efficiency is high. Conclusion: We successfully synthesized dual-modal MR and fluorescence imaging mPEG-Lys3-CA4-NR/SPION polymeric micelles with an ultra-small size and high MRI sensitivity, which were effectively and quickly uptaken into Raw 264.7 cells. mPEG-Lys3-CA4-NR/SPION polymeric micelles might become a new MR lymphography contrast agent, with high effectiveness and high MRI sensitivity.

Energy-converting biomaterials for cancer therapy: Category, efficiency, and biosafety.

Energy-converting biomaterials (ECBs)-mediated cancer-therapeutic modalities have been extensively explored, which have achieved remarkable benefits to overwhelm the obstacles of traditional cancer-treatment modalities. Energy-driven cancer-therapeutic modalities feature their distinctive merits, including noninvasiveness, low mammalian toxicity, adequate therapeutic outcome, and optimistical synergistic therapeutics. In this advanced review, the prevailing mainstream ECBs can be divided into two sections: Reactive oxygen species (ROS)-associated energy-converting biomaterials (ROS-ECBs) and hyperthermia-related energy-converting biomaterials (H-ECBs). On the one hand, ROS-ECBs can transfer exogenous or endogenous energy (such as light, radiation, ultrasound, or chemical) to generate and release highly toxic ROS for inducing tumor cell apoptosis/necrosis, including photo-driven ROS-ECBs for photodynamic therapy, radiation-driven ROS-ECBs for radiotherapy, ultrasound-driven ROS-ECBs for sonodynamic therapy, and chemical-driven ROS-ECBs for chemodynamic therapy. On the other hand, H-ECBs could translate the external energy (such as light and magnetic) into heat for killing tumor cells, including photo-converted H-ECBs for photothermal therapy and magnetic-converted H-ECBs for magnetic hyperthermia therapy. Additionally, the biosafety issues of ECBs are expounded preliminarily, guaranteeing the ever-stringent requirements of clinical translation. Finally, we discussed the prospects and facing challenges for constructing the new-generation ECBs for establishing intriguing energy-driven cancer-therapeutic modalities. This article is categorized under: Nanotechnology Approaches to Biology >Nanoscale Systems in Biology.

Effect of PEG-PDLLA polymeric nanovesicles loaded with doxorubicin and hematoporphyrin monomethyl ether on human hepatocellular carcinoma HepG2 cells in vitro.

OBJECTIVE: To evaluate the cytotoxicity of poly(ethylene glycol)-block-poly(D,L-lactic acid) (PEG-PDLLA) nanovesicles loaded with doxorubicin (DOX) and the photosensitizer hematoporphyrin monomethyl ether (HMME) on human hepatocellular carcinoma HepG2 cells and to investigate potential apoptotic mechanisms. METHODS: PEG-PDLLA nanovesicles were simultaneously loaded with DOX and HMME (PEG-PDLLA-DOX-HMME), and PEG-PDLLA nanovesicles were loaded with DOX (PEG-PDLLA-DOX), HMME (PEG-PDLLA-HMME), or the PEG-PDLLA nanovesicle alone as controls. The cytotoxicity of PEG-PDLLA-DOX-HMME, PEG-PDLLA-DOX, PEG-PDLLA-HMME, and PEG-PDLLA against HepG2 cells was measured, and the cellular reactive oxygen species, percentage of cells with mitochondrial membrane potential depolarization, and apoptotic rate following treatment were determined. RESULTS: Four nanovesicles (PEG-PDLLA-DOX-HMME, PEG-PDLLA-DOX, PEG-PDLLA-HMME, and PEG-PDLLA) were synthesized, and mean particle sizes were 175±18 nm, 154±3 nm, 196±2 nm, and 147±15 nm, respectively. PEG-PDLLA-DOX-HMME was more cytotoxic than PEG-PDLLA-DOX, PEG-PDLLA-HMME, and PEG-PDLLA. PEG-PDLLA-HMME-treated cells had the highest mean fluorescence intensity, followed by PEG-PDLLA-DOX-HMME-treated cells, whereas PEG-PDLLA-DOX- and PEG-PDLLA-treated cells had a similar fluorescence intensity. Mitochondrial membrane potential depolarization was observed in 54.2%, 59.4%, 13.8%, and 14.8% of the cells treated with PEG-PDLLA-DOX-HMME, PEG-PDLLA-HMME, PEG-PDLLA-DOX, and PEG-PDLLA, respectively. The apoptotic rate was significantly higher in PEG-PDLLA-DOX-HMME-treated cells compared with PEG-PDLLA-DOX- and PEG-PDLLA-HMME-treated cells. CONCLUSION: The PEG-PDLLA nanovesicle, a drug delivery carrier, can be simultaneously loaded with two anticancer drugs (hydrophilic DOX and hydrophobic HMME). PEG-PDLLA-DOX-HMME cytotoxicity to HepG2 cells is significantly higher than the PEG-PDLLA nanovesicle loaded with DOX or HMME alone, and DOX and HMME have a synergistic effect against human hepatocellular carcinoma HepG2 cells.

Folate-targeted polymeric micelles loaded with ultrasmall superparamagnetic iron oxide: combined small size and high MRI sensitivity.

Targeted delivery of contrast agents is a highly desirable strategy for enhancing diagnostic efficiency and reducing side effects and toxicity. Water-soluble and tumor-targeting superparamagnetic iron oxide nanoparticles (SPIONs) were synthesized by loading hydrophobic SPIONs into micelles assembled from an amphiphilic block copolymer poly(ethylene glycol)- poly(ε-caprolactone) (PEG-PCL) bearing folate in the distal ends of PEG chains. Compared to the water-soluble SPIONs obtained by small molecular surfactant coating, ultrasmall SPION encapsulation with PEG-PCL micelles (PEG-PCL-SPIONs) simultaneously increases transverse (r(2)) and decreases longitudinal (r(1)) magnetic resonance (MR) relaxivities of water proton in micelle solution, leading to a notably high r(2)/r(1) ratio up to 78, which makes the PEG-PCL-SPIONs a highly sensitive MR imaging (MRI) T(2) contrast agent. The mean size of folate-attached SPION micelles (Fa-PEG-PCL-SPIONs) is 44 ± 3 nm on average, ideal for in vivo MRI applications in which long circulation is greatly determined by small particle size and is highly desirable. Prussian blue staining of BEL-7402 cells over-expressing folate receptors, after incubation with micelle-containing medium, demonstrated that folate functionalization of the magnetic particles significantly enhanced their cell uptake. The potential of Fa-PEG-PCL-SPIONs as a potent MRI probe for in vivo tumor detection was assessed. At 3 hours after intravenous injection of the Fa-PEG-PCL-SPION solution into mice bearing subcutaneous xenografts of human BEL-7402 hepatoma, a 41.2% signal intensity decrease was detected in the T(2)-weighted MR images of the tumor, indicating the efficient accumulation of Fa-PEG-PCL-SPIONs in the tumor tissue.

Folate-functionalized polymeric micelles based on biodegradable PEG-PDLLA as a hepatic carcinoma-targeting delivery system.

Targeted delivery of anti-cancer drugs is a highly desirable strategy to improve therapeutic outcome because of the combination of enhanced efficacy and reduced toxicity. In this study, the anti-cancer drug doxorubicin (DOX) was accommodated in the cores of polymeric micelles self-assembled from amphiphilic block copolymers of poly(ethylene glycol)(PEGs) and poly(D,L-lactide) (PDLLA) with a targeting ligand (folate) attached to the distal ends of the PEG (Folate-PEG-PDLLA). In vitro tumor cell targeting efficacy was evaluated upon observing cellular uptake of these micelles by human hepatic carcinoma cells (Bel 7402 cells) overexpressing surface receptors for folate. In control release tests, DOX behavior of controlled release in folate receptor-mediated micellar folate-PEG-PDLLA-DOX-micelles was obvious, with pH sensitivity. Bel 7402 cells showed micelles to have low toxicity and suggested potential therapeustic application as a multifunctional platform for tumor management.

Folate-functionalized polymeric micelle as hepatic carcinoma-targeted, MRI-ultrasensitive delivery system of antitumor drugs.

Targeted delivery is a highly desirable strategy to improve the diagnostic imaging and therapeutic outcome because of enhanced efficacy and reduced toxicity. In the current research, anticancer drug doxorubicin (DOX) and contrast agent for magnetic resonance imaging (MRI), herein superparamagnetic ion oxide Fe(3)O(4) (SPIO), were accommodated in the core of micelles self-assembled from amphiphilic block copolymer of poly(ethylene glycol) (PEG) and poly(epsilon-caprolactone) (PCL) with a targeting ligand (folate) attached to the distal ends of PEG (Folate-PEG-PCL). The in vitro tumor cell targeting efficacy of these folate functionalized and DOX/SPIO-loaded micelles (Folate-SPIO-DOX-Micelles) was evaluated upon observing cellular uptake of micelles by human hepatic carcinoma cells (Bel 7402 cells) which overexpresses surface receptors for folic acid. In the Prussian blue staining experiments, cells incubated with Folate-SPIO-DOX-Micelles showed much higher intracellular iron density than the cells incubated with the folate-free SPIO-DOX-Micelles. According to the flow cytometry data, cellular DOX uptake observed for the folate targeting micelle was about 2.5 fold higher than that for the non-targeting group. Furthermore, MTT assay showed that Folate-SPIO-DOX-Micelles effectively inhibited cell proliferation, while the folate-free SPIO-DOX-Micelles did not show the same feat at comparable DOX concentrations. The potential of Folate-SPIO-DOX-Micelle as a novel MRI-visible nanomedicine platform was assessed with a 1.5 T clinical MRI scanner. The acquired MRI T (2) signal intensity of cells treated with the folate targeting micelles decreased significantly. By contrast, T (2) signal did not show obvious decrease for cells treated with the folate-free micelles. Our results indicate that the multifunctional polymeric micelles, Folate-SPIO-DOX-Micelles, have better targeting tropism to the hepatic carcinoma cells in vitro than their non-targeting counterparts, and the cell targeting events of micelles can be monitored using a clinical MRI scanner.