Highly Efficient Glioma Targeting of Tat Peptide-TTA1 Aptamer-Polyephylene Glycol-Modified Gelatin-Siloxane Nanoparticles.

Gliomas are the most common type of intracranial malignant tumor; however, current treatment approaches are often ineffective due to limited penetration of genes or drugs through the blood-brain barrier (BBB). Here we describe the synthesis of gelatin-siloxane nanoparticles (GS NPs) as candidate gene carriers through a two-step sol-gel process. To increase the efficiency of glioma targeting, human immunodeficiency virus-derived Tat, tumor-targeting aptamer (TTA)1, and polyethylene glycol (PEG) were conjugated to the GS NPs to generate Tat-TTA1-PEG-GS NPs. In vivo imaging revealed that these modified NPs not only evaded capture by the reticulo-endothelial system, but were able to cross the BBB to reach gliomas. Our results suggest that Tat-TTA1-PEG-GS NPs are a new type of non-viral vector that can deliver therapeutic DNA or drugs for highly efficient glioma treatment.

[Research on Tat peptide-polyethylene glycol modified gelatin-siloxane nanoparticles across the blood-brain barrier].

Gelatin-siloxane nanoparticles (GS NPs) have been considered to be good gene carrier candidate in vitro, since they have several advantages such as low toxicity, easy preparation and surface modification. In this study, the Tat-PEG-GS NPs were synthesized by the gelatin-siloxane, surface-modified with the polyethylene glycol (H2 N-PEG-COOH) and Tat peptide (KYGRRRQRRKKRGC) and thus constructed a delivery system which can cross BBB (Blood-brain barrier). The morphology, diameter, and zeta potential of Tat-PEG-GS NPs carrier system were characterized with transmission electron microscopy (TEM) and Nano-ZS zetasizer dynamic light scattering Detector. The organ distribution and dynamic evolution localized in the brain parenchyma of Tat-PEG-GS NPs in vivo was investigated with Cri in vivo imaging system and TEM. The obtained Tat-PEG-GS NPs were approximately spherical in shape with average particle size of 150-200 nm and zeta potentials of (32.27 +/- 2.47) mV. In vivo imaging results showed that the accumulation of Tat-PEG-GS NPs was higher in the brain than the accumulation of PEG-GS NPs, but the accumulation of Tat-PEG-GS NPs was lower in the liver than the accumulation of PEG-GS NPs. These differences are statistically significant. The nanocomplex could cross the BBB and reach the neural tissues tested with TEM. The Tat-PEG-GS NPs could cross the BBB and escape the arrest of the reticuloendothelial system (RES), and it would be potential nano-carrier systems for central delivery.

Tat peptide-decorated gelatin-siloxane nanoparticles for delivery of CGRP transgene in treatment of cerebral vasospasm.

BACKGROUND: Gene transfer using a nanoparticle vector is a promising new approach for the safe delivery of therapeutic genes in human disease. The Tat peptide-decorated gelatin-siloxane (Tat-GS) nanoparticle has been demonstrated to be biocompatible as a vector, and to have enhanced gene transfection efficiency compared with the commercial reagent. This study investigated whether intracisternal administration of Tat-GS nanoparticles carrying the calcitonin gene-related peptide (CGRP) gene can attenuate cerebral vasospasm and improve neurological outcomes in a rat model of subarachnoid hemorrhage. METHOD: A series of gelatin-siloxane nanoparticles with controlled size and surface charge was synthesized by a two-step sol-gel process, and then modified with the Tat peptide. The efficiency of Tat-GS nanoparticle-mediated gene transfer of pLXSN-CGRP was investigated in vitro using brain capillary endothelial cells and in vivo using a double-hemorrhage rat model. For in vivo analysis, we delivered Tat-GS nanoparticles encapsulating pLXSN-CGRP intracisternally using a double-hemorrhage rat model. RESULTS: In vitro, Tat-GS nanoparticles encapsulating pLXSN-CGRP showed 1.71 times higher sustained CGRP expression in endothelial cells than gelatin-siloxane nanoparticles encapsulating pLXSN-CGRP, and 6.92 times higher CGRP expression than naked pLXSN-CGRP. However, there were no significant differences in pLXSN-CGRP entrapment efficiency and cellular uptake between the Tat-GS nanoparticles and gelatin-siloxane nanoparticles. On day 7 of the in vivo experiment, the data indicated better neurological outcomes and reduced vasospasm in the subarachnoid hemorrhage group that received Tat-GS nanoparticles encapsulating pLXSN-CGRP than in the group receiving Tat-GS nanoparticles encapsulating pLXSN alone because of enhanced vasodilatory CGRP expression in cerebrospinal fluid. CONCLUSION: Overexpression of CGRP attenuated vasospasm and improved neurological outcomes in an experimental rat model of subarachnoid hemorrhage. Tat-GS nanoparticle-mediated CGRP gene delivery could be an innovative strategy for treatment of cerebral vasospasm after subarachnoid hemorrhage.

Multifunctional ZnPc-loaded mesoporous silica nanoparticles for enhancement of photodynamic therapy efficacy by endolysosomal escape.

The cellular uptake and localization of photosensitizer-loaded nanoparticles have significant impact on photodynamic therapy (PDT) efficacy due to short lifetime and limited action radius of singlet oxygen. Herein, we develop poly(ethylene glycol) (PEG)- and polyethylenimine (PEI)-functionalized zinc(II) phthalocyanine (ZnPc)-loaded mesoporous silica nanoparticles (MSNs), which are able to distribute in the cytosol by endolysosomal escape. In this photosensitizer-carrier system (PEG-PEI-MSNs/ZnPc), ZnPc is a PDT agent; MSNs are the nanocarrier for encapsulating ZnPc; PEI facilitates endosomal escape; and PEG enhances biocompatibility. The as-synthesized PEG-PEI-MSNs/ZnPc have a high escape efficiency from the lysosome to the cytosol due to the "proton sponge" effect of PEI. Compared with the ZnPc-loaded MSNs, the phototoxicity of the PEG-PEI-MSNs/ZnPc is greatly enhanced in vitro. By measuring the mitochondrial membrane potential, a significant loss of >80% Δψm after treatment with PEG-PEI-MSNs/ZnPc-PDT is observed. It is further demonstrated that the ultra-efficient passive tumor targeting and excellent PDT efficacy are achieved in tumor-bearing mice upon intravenous injection of PEG-PEI-MSNs/ZnPc and the followed light exposure. We present here a strategy for enhancement of PDT efficacy by endolysosomal escape and highlight the promise of using multifunctional MSNs for cancer therapy.

In vitro and in vivo studies on gelatin-siloxane nanoparticles conjugated with SynB peptide to increase drug delivery to the brain.

BACKGROUND: Nanobiotechnology can provide more efficient tools for diagnosis, targeted and personalized therapy, and increase the chances of brain tumor treatment being successful. Use of nanoparticles is a promising strategy for overcoming the blood-brain barrier and delivering drugs to the brain. Gelatin-siloxane (GS) nanoparticles modified with Tat peptide can enhance plasmid DNA transfection efficiency compared with a commercial reagent. METHODS: SynB-PEG-GS nanoparticles are membrane-penetrable, and can cross the blood-brain barrier and deliver a drug to its target site in the brain. The efficiency of delivery was investigated in vivo and in vitro using brain capillary endothelial cells, a cocultured blood-brain barrier model, and a normal mouse model. RESULTS: Our study demonstrated that both SynB-PEG-GS and PEG-GS nanoparticles had a spherical shape and an average diameter of 150-200 nm. It was shown by MTT assay that SynB-PEG-GS nanoparticles had good biocompatibility with brain capillary endothelial cells. Cellular uptake by SynB-PEG-GS nanoparticles was higher than that for PEG-GS nanoparticles for all incubation periods. The amount of SynB-PEG-GS nanoparticles crossing the cocultured blood-brain barrier model was significantly higher than that of PEG-GS nanoparticles at all time points measured (P < 0.05). In animal testing, SynB-PEG-GS nanoparticle levels in the brain were significantly higher than those of PEG-GS nanoparticles at all time points measured (P < 0.01). In contrast with localization in the brain, PEG-GS nanoparticle levels were significantly higher than those of SynB-PEG-GS nanoparticles (P < 0.01) in the liver. CONCLUSION: This study indicates that SynB-PEG-GS nanoparticles have favorable properties with regard to morphology, size distribution, and toxicity. Moreover, the SynB-PEG-GS nanoparticles exhibited more efficient brain capillary endothelial cell uptake and improved crossing of the blood-brain barrier. Further, biodistribution studies of rhodamine-loaded nanoparticles demonstrated that modification with the SynB peptide could not only improve the ability of PEG-GS nanoparticles to evade capture in the reticuloendothelial system but also enhance their efficiency in crossing the blood-brain barrier.

Enhanced brain targeting of temozolomide in polysorbate-80 coated polybutylcyanoacrylate nanoparticles.

BACKGROUND: Polybutylcyanoacrylate (PBCA) nanoparticles coated with polysorbate-80 have been extensively proposed for delivering drugs into the animal brain and have shown great potential for therapeutic applications. In this study, we made an attempt to deliver the chemotherapeutic drug, temozolomide, into the brain by using PBCA nanoparticles. The physicochemical characteristics, in vitro release, and brain targeting ability of the drug-loaded nanoparticles were investigated. RESULTS: Our results show that a significantly higher concentration of temozolomide in the form of polysorbate-80-coated PBCA nanoparticles was observed in the brain (P < 0.05) in comparison with the free drug. CONCLUSION: This study indicates that polysorbate-80 coated PBCA nanoparticles could be a feasible carrier for temozolomide delivery to the brain. It is anticipated that the developed formulation may improve on targeted therapy for malignant brain tumors in the future.