Chitosan Combined with Poly-L-arginine as Efficient, Safe, and Serum-Insensitive Vehicle with RNase Protection Ability for siRNA Delivery

Chitosan (CS) combined with poly-L-arginine (PLA) was formulated and evaluated for its performance to deliver siRNA to HeLa cells expressing enhanced green fluorescent protein (EGFP). Compared with the formulations using single polymer in which the polyplexes were completely formed at the weight ratio of >20 : 1 for CS/siRNA or 1 : 1 for PLA/siRNA, the combination of CS and PLA could reduce the amounts of the polymers required for the complete complexation with siRNA, thereby forming positively charged, nanosized polyplex at the weight ratio of CS/PLA/siRNA of 5 : 0.5: 1. In addition, while the transfection efficiency of CS/siRNA and PLA/siRNA was very low at physiological pH (7.4), CS/PLA/siRNA at the optimal weight ratio of 5 : 0.5 : 1 satisfactorily silenced the endogenous EGFP gene at pH 7.4 as well as at pH 6.4 without the deterrent effect from serum. The combined polymers could protect siRNA from RNase degradation over a period of at least 6 h. Furthermore, MTT assay results demonstrated that CS/PLA/siRNA complexes showed acceptably low cytotoxicity with 75% cell viability. Therefore, CS combined with PLA is easy to prepare, safe, and promising for use as an efficient siRNA delivery vehicle

Kinetic Monte-Carlo Simulation of Methane Steam Reforming over a Nickel Surface

A kinetic Monte-Carlo model was developed in order to simulate the methane steam reforming and kinetic behavior of this reaction. There were 34 elementary step reactions that were used, based on the Langmuir–Hinshelwood mechanism, over a nickel catalyst. The simulation was investigated at a mole fraction of methane between 0.1 and 0.9, temperature of 600 to 1123 K, and total pressure of up to 40 bar. The simulated results were collected at a steady state and were compared with the previously reported experiments. The fractional coverages of the adsorbed species and the production rates of H2, CO, and CO2 were evaluated, and the effects of the reaction temperature, feed concentration, and total pressure of reactants were also investigated. The simulation results showed a similar trend with previous experimental results, and suggested the appropriate conditions for this reaction, which were a total pressure of 10 bar, with the mole fraction of methane in a range of 0.4–0.5

Influence of serum on DNA protection ability and transfection efficiency of cationic lipid-based nanoparticles for gene delivery

Cationic lipid-based nanoparticulate systems are delivery systems that has been widely used in pharmaceutical field including gene delivery. There are many barriers obstructing genetic materials and their delivery systems to reach the target. Serum is one of the imperative factor that should be investigated. Therefore, the aim of this study was to examine the effect of serum on DNA protection ability of spermine-liposomes and niosomes by evaluating the percentage of transfection efficiency in Hela cell and observing the DNA degradation band using agarose gel electrophoresis in the presence of serum. The results showed that the percentage of transfection efficiency of spermine-liposomes was dramatically decreased when serum is presented (p< 0.05). In contrast, whether or not the serum is presented, the spermine-niosomes showed no significant difference in transfection efficiency. Concisely, liposomes could slightly protect DNA from DNase in the serum, whereas, niosomes had potential ability to protect DNA from the enzymes in serum. This result revealed an advantage of the cationic niosomes system as a gene carrier over the cationic liposomes

Influence of serum on DNA protection ability and transfection efficiency of cationic lipid-based nanoparticles for gene delivery

Cationic lipid-based nanoparticulate systems are delivery systems that has been widely used in pharmaceutical field including gene delivery. There are many barriers obstructing genetic materials and their delivery systems to reach the target. Serum is one of the imperative factor that should be investigated. Therefore, the aim of this study was to examine the effect of serum on DNA protection ability of spermine-liposomes and niosomes by evaluating the percentage of transfection efficiency in Hela cell and observing the DNA degradation band using agarose gel electrophoresis in the presence of serum. The results showed that the percentage of transfection efficiency of spermine-liposomes was dramatically decreased when serum is presented (p< 0.05). In contrast, whether or not the serum is presented, the spermine-niosomes showed no significant difference in transfection efficiency. Concisely, liposomes could slightly protect DNA from DNase in the serum, whereas, niosomes had potential ability to protect DNA from the enzymes in serum. This result revealed an advantage of the cationic niosomes system as a gene carrier over the cationic liposomes

siRNA Targeting Mcl-1 Potentiates the Anticancer Activity of Andrographolide Nanosuspensions via Apoptosis in Breast Cancer Cells

Breast cancer is the second leading cause of cancer-related death in the US. However, recurrence is frequently found despite adjuvant therapy being available. Combination therapy with cytotoxic drugs and gene therapy is being developed to be a new promising cancer treatment strategy. Introducing substituted dithiocarbamate moieties at the C12 position of andrographolide (3nAG) could improve its anticancer selectivity in the MCF-7 breast cancer cell line. However, its hydrophobicity is one of its main drawbacks. This work successfully prepared 3nAG nanosuspension stabilized with the chitosan derivative NSC (3nAGN-NSC) to increase solubility and pharmacological effectiveness. siRNAs have emerged as a promising therapeutic alternative for interfering with particular mRNA. The 3nAGN-NSC had also induced Mcl-1 mRNA expression in MCF-7 human breast cancer cells at 8, 12, and 24 h. This indicates that, in addition to Mcl-1 silencing by siRNA (siMcl-1) in MCF-7 with substantial Mcl-1 reliance, rationally devised combination treatment may cause the death of cancer cells in breast cancer. The Fa-CI analysis showed that the combination of 3nAGN-NSC and siMcl-1 had a synergistic effect with a combination index (CI) value of 0.75 (CI < 1 indicating synergistic effects) at the fractional inhibition of Fa 0.7. The synergistic effect was validated by flow cytometry, with the induction of apoptosis as the mechanism of reduced cell viability. Our findings suggested the rational use of 3nAGN-NSC in combination with siMcl-1 to kill breast cancer cells