Synthesis, characterization, and evaluation of a novel amphiphilic polymer RGD-PEG-Chol for target drug delivery system

Functionalized Fluorescent Nanodiamonds for Simultaneous Drug Delivery and Quantum Sensing in HeLa Cells

Here, we present multifunctional fluorescent nanodiamonds (FNDs) for simultaneous drug delivery and free radical detection. For this purpose, we modified FNDs containing nitrogen vacancy (NV) centers with a diazoxide derivative. We found that our particles enter cells more easily and are able to deliver this cancer drug into HeLa cells. The particles were characterized by infrared spectroscopy, dynamic light scattering, and secondary electron microscopy. Compared to the free drug, we observe a sustained release over 72 h rather than 12 h for the free drug. Apart from releasing the drug, with these particles, we can measure the drug's effect on free radical generation directly. This has the advantage that the response is measured locally, where the drug is released. These FNDs change their optical properties based on their magnetic surrounding. More specifically, we make use of a technique called relaxometry to detect spin noise from the free radical at the nanoscale with subcellular resolution. We further compared the results from our new technique with a conventional fluorescence assay for the detection of reactive oxygen species. This provides a new method to investigate the relationship between drug release and the response by the cell via radical formation or inhibition.

Controlling the Biological Fate of Liposomal Spherical Nucleic Acids Using Tunable Polyethylene Glycol Shells

Liposomal spherical nucleic acids (LSNAs) modified with polyethylene glycol (PEG) units are studied in an attempt to understand how the circulation time and biodistribution of the constructs can be manipulated. Specifically, the effect of (1) PEG molecular weight, (2) PEG shell stability, and (3) PEG modification method (PEG in both the core and shell versus PEG in the shell only) on LSNA blood circulation, biodistribution, and in vivo cell internalization in a syngeneic, orthotopic triple-negative breast cancer mouse model is studied. Generally, high PEG molecular weight extends blood circulation lifetime, and a more lipophilic anchor stabilizes the PEG shell and improves circulation and tumor accumulation but at the cost of cell uptake efficiency. The PEGylation strategy has a minor effect on in vitro properties of LSNAs but significantly alters in vivo cell uptake. For example, surface-only PEG in one design contributed to higher in vivo cell internalization than its counterpart with PEG both in the shell and core. Taken together, this work provides guidelines for designing LSNAs that exhibit maximal in vivo cancer cell uptake characteristics in the context of a breast cancer model.

Fmoc-PEG Coated Single-Wall Carbon Nanotube Carriers by Non-covalent Functionalization: An Experimental and Molecular Dynamics Study

Due to their structural characteristics at the nanoscale level, single-walled carbon nanotubes (SWNTs), hold great promise for applications in biomedicine such as drug delivery systems. Herein, a novel single-walled carbon nanotube (SWNT)-based drug delivery system was developed by conjugation of various Fmoc-amino acid bearing polyethylene glycol (PEG) chains (Mw = 2,000, 5,000, and 12,000). In the first step, full-atom molecular dynamics simulations (MD) were performed to identify the most suitable Fmoc-amino acid for an effective surface coating of SWNT. Fmoc-glycine, Fmoc-tryptophan, and Fmoc-cysteine were selected to attach to the PEG polymer. Here, Fmoc-cysteine and -tryptophan had better average interaction energies with SWNT with a high number of aromatic groups, while Fmoc-glycine provided a non-aromatic control. In the experimental studies, non-covalent modification of SWNTs was achieved by Fmoc-amino acid-bearing PEG chains. The remarkably high amount of Fmoc-glycine-PEG, Fmoc-tryptophan-PEG, and Fmoc-cysteine-PEG complexes adsorbed onto the SWNT surface, as was assessed via thermogravimetric and UV-vis spectroscopy analyses. Furthermore, Fmoc-cysteine-PEG5000 and Fmoc-cysteine-PEG12000 complexes displayed longer suspension time in deionized water, up to 1 and 5 week, respectively, underlying the ability of these surfactants to effectively disperse SWNTs in an aqueous environment. In vitro cell viability assays on human dermal fibroblast cells also showed the low cytotoxicity of these two samples, even at high concentrations. In conclusion, synthesized nanocarriers have a great potential for drug delivery systems, with high loading capacity, and excellent complex stability in water critical for biocompatibility.

Polymeric Drug Delivery Systems Bearing Cholesterol Moieties: A Review

This review aims to provide an overview of polymers comprising cholesterol moiety/ies designed to be used in drug delivery. Over the last two decades, there have been many papers published in this field, which are summarized in this review. The primary focus of this article is on the methods of synthesis of polymers bearing cholesterol in the main chain or as side chains. The data related to the composition, molecular weight, and molecular weight distribution of polymers are presented. Moreover, other aspects, such as forms of carriers, types of encapsulated drugs, encapsulation efficiency and capacity, are also included.

Synergistic Effect of Tangeretin and Atorvastatin for Colon Cancer Combination Therapy: Targeted Delivery of These Dual Drugs Using RGD Peptide Decorated Nanocarriers

Purpose

Colorectal cancer (CRC) is the third most frequently diagnosed cancer and the fourth leading cause of cancer death over the world. Nano-sized drug delivery systems are used for the treatment of cancers. The aim of this study was to develop a tangeretin (TAGE) and atorvastatin (ATST) combined nano-system decorated with RGD (RGD-ATST/TAGE CNPs) for colon cancer combination therapy.

Materials and Methods

In this study, cyclized arginine-glycine-aspartic acid sequences (RGD) contained ligand was synthesized by conjugating cyclo (Arg-Gly-Asp-d-Phe-Lys) (cRGDfK) with D-α-tocopheryl succinate dichloromethane (TOSD) using polyethylene glycol (PEG) as a linker to obtain cRGDfK-PEG-TOSD. ATST and TAGE combined nano-systems: RGD-ATST/TAGE CNPs were prepared. The combination effects as well as antitumor effects of these two agents were evaluated on colon cancer cells and mice bearing cancer models.

Results

Drug entrapment efficiencies of nano-systems were high (around 90%), suggesting the good loading capacity. The release profiles of ATST or TAGE from RGD-ATST/TAGE CNPs followed Higuchi model. The RGD-decorated nano-system showed more obvious cytotoxicity on HT-29 cells than the undecorated nano-system, but no obvious difference was found on normal CCD-18 cells. The strongest synergism was observed when the weight ratio of ATST to TAGE was 1:1. In vivo biodistribution of RGD-ATST/TAGE CNPs in the tumor site is high and prominently inhibited the in vivo tumor growth.

Conclusion

The results demonstrated that RGD-ATST/TAGE CNPs showed the most significant synergistic therapeutic efficacy, exhibited no significant toxicity to major organs and tissues, and body weight of the treated mice was stable. Therefore, the combination nano-system is a promising platform for colon cancer therapy.

c[RGDyk]-coated liposomes loaded with adriamycin and miR-21 mimics inhibit the growth of hepatoma cell line SMCC-7721 via up-regulating Bax and p53

BACKGROUND

This study was conducted to investigate the effects of c[RGDyk]-coated liposomes loaded with Adriamycin (nanodrug) and miR-21 mimics on hepatoma cell line SMCC-7721.

METHODS

SMCC-7721 cells were divided into five groups: control (receiving no treatment), nanodrug, miR-21 mimics + nanodrug and miR-21 mimics and empty vector. The concentration and duration of treatments were determined using the MTT assay. Cell apoptosis was detected using flow cytometer. The expression of Bax, Bcl-2 and p53 was measured using qPCR and Western blot analysis.

RESULTS

MTT showed that the nanodrug inhibited cell proliferation. Nanodrug and miR-21 led to cell arrest at S phase and apoptosis. qPCR showed that cells treated with nanodrug and miR-21 increased the expression of Bax and p53. Western blot analysis indicated that Bcl-2 expression was significantly reduced.

CONCLUSIONS

Our work demonstrates that nanodrug and miR-21 have inhibitory effect on SMCC-7721 cells via up-regulating Bax and p53.

Cleavable PEGylation: a strategy for overcoming the "PEG dilemma" in efficient drug delivery

To prolong the circulation time of drug, PEGylation has been widely used via the enhanced permeability and retention (EPR) effect, thereby providing new hope for better treatment. However, PEGylation also brings the "PEG dilemma", which is difficult for the cellular absorption of drugs and subsequent endosomal escape. As a result, the activity of drugs is inevitably lost after PEG modification. To achieve successful drug delivery for effective treatment, the crucial issue associated with the use of PEG-lipids, that is, “PEG dilemma” must be addressed. In this paper, we introduced the development and application of nanocarriers with cleavable PEGylation, and discussed various strategies for overcoming the PEG dilemma. Compared to the traditional ones, the vehicle systems with different environmental-sensitive PEG-lipids were discussed, which cleavage can be achieved in response to the intracellular as well as the tumor microenvironment. This smart cleavable PEGylation provides us an efficient strategy to overcome “PEG dilemma”, thereby may be a good candidate for the cancer treatment in future.

DUP1 peptide modified micelle efficiently targeted delivery paclitaxel and enhance mitochondrial apoptosis on PSMA-negative prostate cancer cells

Prostate tumor cell targeted peptide fragment conjugated to the nano drug delivery system is a promising strategy for prostate cancer therapy. In this work, an amphiphilic copolymer Chol–PEG–DUP1 (PEG–cholesterol conjugated with DUP1 peptide) has been synthesized and characterized by proton nuclear magnetic resonance spectrum (¹H NMR). The paclitaxel (PTX) was encapsulated into the Chol–PEG–DUP1 micelles to obtain aqueous formulation with small particle size (within 200 nm) and high drug encapsulating efficiency. The DUP1 modified PTX micelle significantly enhanced the cytotoxicity of paclitaxel to PSMA negative prostate tumor cells (PC-3 cell) as demonstrated by MTT (IC₅₀ = 15.8 μg/mL compared to 68.7 μg/mL of free PTX). Flow cytometry analysis and fluorescence images revealed the DUP1 peptide fragments on the surface of micelles increased drug uptake (2.08-fold) by PC-3 cells. Flow cytometry and immunoblotting analysis showed the DUP1 modified PTX micelle enhanced the mitochondrial apoptosis-inducing capacity of PTX to PC-3 cells. In conclusion, Chol–PEG–DUP1 modified micelle was a reasonable, facile, and economic drug delivery system to target the PSMA-negative prostate cancer.

Discovery and in vivo evaluation of novel RGD-modified lipid-polymer hybrid nanoparticles for targeted drug delivery

In the current study, the lipid-shell and polymer-core hybrid nanoparticles (lpNPs) modified by Arg–Gly–Asp(RGD) peptide, loaded with curcumin (Cur), were developed by emulsification-solvent volatilization method. The RGD-modified hybrid nanoparticles (RGD–lpNPs) could overcome the poor water solubility of Cur to meet the requirement of intravenous administration and tumor active targeting. The obtained optimal RGD-lpNPs, composed of PLGA (poly(lactic-co-glycolic acid))–mPEG (methoxyl poly(ethylene- glycol)), RGD–polyethylene glycol (PEG)–cholesterol (Chol) copolymers and lipids, had good entrapment efficiency, submicron size and negatively neutral surface charge. The core-shell structure of RGD–lpNPs was verified by TEM. Cytotoxicity analysis demonstrated that the RGD–lpNPs encapsulated Cur retained potent anti-tumor effects. Flow cytometry analysis revealed the cellular uptake of Cur encapsulated in the RGD–lpNPs was increased for human umbilical vein endothelial cells (HUVEC). Furthermore, Cur loaded RGD–lpNPs were more effective in inhibiting tumor growth in a subcutaneous B16 melanoma tumor model. The results of immunofluorescent and immunohistochemical studies by Cur loaded RGD–lpNPs therapies indicated that more apoptotic cells, fewer microvessels, and fewer proliferation-positive cells were observed. In conclusion, RGD–lpNPs encapsulating Cur were developed with enhanced anti-tumor activity in melanoma, and Cur loaded RGD–lpNPs represent an excellent tumor targeted formulation of Cur which might be an attractive candidate for cancer therapy.