Tuning the Potency of Farnesol-Modified Polyethylenimine with Polyanionic Trans-Booster to Enhance DNA Delivery.

Low molecular weight polyethylenimine (PEI) based lipopolymers become an attractive strategy to construct nonviral therapeutic carriers with promising transfection efficiency and minimal toxicity. Herein, this paper presents the design and synthesis of novel farnesol (Far) conjugated PEI, namely PEI1.2k-SA-Far7. The polymers had quick DNA complexation, effective DNA unpacking (dissociation), and cellular uptake abilities when complexed with plasmid DNA. However, they were unable to provide robust transfection in culture, indicating inability of Far grafting to improve the transfection efficacy significantly. To overcome this limitation, the commercially available polyanionic Trans-Booster additive, which is capable of displaying electrostatic interaction with PEI1.2k-SA-Far7, has been used to enhance the uptake of pDNA polyplexes and transgene expression. pDNA condensation was successfully achieved in the presence of the Trans-Booster with more stable polyplexes, and in vitro transfection efficacy of the polyplexes was improved to be comparable to that obtained with an established reference reagent. The PEI1.2k-SA-Far7/pDNA/Trans-Booster ternary complex exhibited good compatibility with cells and minimal hemolysis activity. This work demonstrates the exemplary potency of using additives in polyplexes and the potential of resultant ternary complexes for effective pDNA delivery.

Biodistribution of Therapeutic Small Interfering RNAs Delivered with Lipid-Substituted Polyethylenimine-Based Delivery Systems.

Small interfering RNAs (siRNAs) have emerged as a powerful tool to manipulate gene expression in vitro. However, their potential therapeutic application encounters significant challenges, such as degradation in vivo, limited cellular uptake, and restricted biodistribution, among others. This study evaluates the siRNA delivery efficiency of three different lipid-substituted polyethylenimine (PEI)-based carriers, named Leu-Fect A-C, to different organs in vivo, including xenograft tumors, when injected into the bloodstream of mice. The siRNA analysis was undertaken by stem-loop RT-PCR, followed by qPCR or digital droplet PCR. Formulating siRNAs with a Leu-Fect series of carriers generated nanoparticles that effectively delivered the siRNAs into K652 and MV4-11 cells, both models of leukemia. The Leu-Fect carriers were able to successfully deliver BCR-Abl and FLT3 siRNAs into leukemia xenograft tumors in mice. All three carriers demonstrated significantly enhanced siRNA delivery into organs other than the liver, including the xenograft tumors. Preferential biodistribution of siRNAs was observed in the lungs and spleen. Among the delivery systems, Leu-Fect A exhibited the highest biodistribution into organs. In conclusion, lipid-substituted PEI-based delivery systems offer improvements in addressing pharmacokinetic challenges associated with siRNA-based therapies, thus opening avenues for their potential translation into clinical practice.

Designing Nanomedicines for Breast Cancer Therapy.

In 2020, breast cancer became the most diagnosed cancer worldwide. Conventional chemotherapies have major side effects due to their non-specific activities. Alternatively, short interfering RNA(siRNA)-carrying nanoparticles (NPs) have a high potential to overcome this non-specificity. Lipid-substituted polyethyleneimine (PEI) polymers (lipopolymers) have been reported as efficient non-viral carriers of siRNA. This study aims to engineer novel siRNA/lipopolymer nanocomplexes by incorporating anionic additives to obtain gene silencing through siRNA activity with minimal nonspecific toxicity. We first optimized our polyplexes in GFP+ MDA-MB-231 cells to effectively silence the GFP gene. Inclusion of phosphate buffer with pH 8.0 as complex preparation media and N-Lauroylsarcosine Sodium Salt as additive, achieved ~80% silencing with the least amount of undesired cytotoxicity, which was persistent for at least 6 days. The survivin gene was then selected as a target in MDA-MB-231 cells since there is no strong drug (i.e., small organic molecule) for inhibition of its oncogenic activity. The qRT-PCR, flow cytometry analysis and MTT assay revealed >80% silencing, ~95% cell uptake and >70% cell killing by the same formulation. We conclude that our lipopolymer can be further investigated as a lead non-viral carrier for breast cancer gene therapy.

Transfection Efficacy and Cellular Uptake of Lipid-Modified Polyethyleneimine Derivatives for Anionic Nanoparticles as Gene Delivery Vectors.

Cationic polyethylenimine (PEI)-based nonviral gene carriers have been desirable to overcome the limitations of viral vectors in gene therapy. A range of PEI derivatives were designed, synthesized, and evaluated for nonviral delivery applications of plasmid DNA (pDNA). Linolenic acid, lauric acid, and oleic acid were covalently conjugated with low-molecular-weight PEI (Mw ∼ 1200 Da) via two different linkers, gallic acid (GA) and p-hydroxybenzoic acid (PHPA), that allows a differential loading of lipids per modified amine (3 vs 1, respectively). 1H NMR spectrum confirmed the expected structure of the conjugates as well as the level of lipid substitution. SYBR Green binding assay performed to investigate the 50% binding concentration (BC50) of lipophilic polymers to pDNA revealed increased BC50 with an increased level of lipid substitution. The particle analysis determined that GA- and PHPA-modified lipopolymers gave pDNA complexes with ∼300 and ∼100 nm in size, respectively. At the polymer/pDNA ratio of 5.0, the ζ-potentials of the complexes were negative (-6.55 to -10.6 mV) unlike the complexes with the native PEI (+11.2 mV). The transfection experiments indicated that the prepared lipopolymers showed higher transfection in attachment-dependent cells than in suspension cells based on the expression of the reporter green fluorescent protein (GFP) gene. When loaded with Cy3-labeled pDNA, the lipopolymers exhibited effective cellular uptake in attachment-dependent cells while the cellular uptake was limited in suspension cells. These results demonstrate the potential of lipid-conjugated PEI via GA and PHPA linkers, which are promising for the modification of anchorage-dependent cells.

Potential of siRNA in COVID-19 therapy: Emphasis on in silico design and nanoparticles based delivery.

Small interfering RNA (siRNA)-mediated mRNA degradation approach have imparted its eminence against several difficult-to-treat genetic disorders and other allied diseases. Viral outbreaks and resulting pandemics have repeatedly threatened public health and questioned human preparedness at the forefront of drug design and biomedical readiness. During the recent pandemic caused by the SARS-CoV-2, mRNA-based vaccination strategies have paved the way for a new era of RNA therapeutics. RNA Interference (RNAi) based approach using small interfering RNA may complement clinical management of the COVID-19. RNA Interference approach will primarily work by restricting the synthesis of the proteins required for viral replication, thereby hampering viral cellular entry and trafficking by targeting host as well as protein factors. Despite promising benefits, the stability of small interfering RNA in the physiological environment is of grave concern as well as site-directed targeted delivery and evasion of the immune system require immediate attention. In this regard, nanotechnology offers viable solutions for these challenges. The review highlights the potential of small interfering RNAs targeted toward specific regions of the viral genome and the features of nanoformulations necessary for the entrapment and delivery of small interfering RNAs. In silico design of small interfering RNA for different variants of SARS-CoV-2 has been discussed. Various nanoparticles as promising carriers of small interfering RNAs along with their salient properties, including surface functionalization, are summarized. This review will help tackle the real-world challenges encountered by the in vivo delivery of small interfering RNAs, ensuring a safe, stable, and readily available drug candidate for efficient management of SARS-CoV-2 in the future.

A pH-sensitive guar gum-grafted-lysine-ß-cyclodextrin drug carrier for the controlled release of 5-flourouracil into cancer cells.

The physiological environment is a crucial factor in biomedical systems, which can be regulated with relative ease both in vitro and in vivo. Control of pH has emerged as a powerful strategy in cancer therapy because pH has a profound effect on the interaction of a polymeric-based drug delivery system with tumor cells. In this regard, the enhancement of pH response capability was demonstrated with a 5-flourouracil (5-FU)-loaded guar gum (GG)-grafted-lysine-ß-cyclodextrin (L-ß-CD) drug carrier. The size, charge, morphology, and encapsulation efficiency of the 5-FU-loaded polymeric carrier were characterized for the control and sustained release of the drug. In a specific cancer pH environment, 5-FU-loaded GG-g-L-ß-CD could rapidly swallow, disassemble, and release 5-FU by accepting or losing electrons. In vitro observations indicate that GG-g-L-ß-CD dramatically releases 5-FU in an acidic environment rather than in a basic environment. In vitro antitumor activity tests showed that 5-FU-loaded GG-g-L-ß-CD had a higher cytotoxicity against KB cells, with an IC50 value of 1.38 µg ml-1. The reactive oxygen species (ROS) generated by 5-FU in the KB cells showed efficient suppression of tumour cell growth. The Hoechst assay revealed the active nature of 5-FU in the cell nucleus of the KB cells. The potential mitochondrial damage by apoptosis in KB cells greatly increased cell death. Therefore, due to its active nature, the pH-sensitive 5-FU-loaded GG-g-L-ß-CD carrier is a potential drug delivery system for safe and effective cancer therapy, and it can be useful for inhibiting tumour cell growth.

Development of extended-voyaging anti-oxidant Linked Amphiphilic Polymeric Nanomicelles for Anti-Tuberculosis Drug Delivery.

Amphiphilic chitosan-graft-poly(caprolactone)/(ferulic acid) (CS-g-PCL/FA) multi-co-polymers were fabricated by microwave-assisted ring opening polymerization followed by an 1-ethyl-3-(3-dimethyl-aminopropyl) carbodiimide (EDC)-mediated coupling reaction and characterized by Fourier transformed infrared (FTIR) spectroscopy. Graft copolymers self-assembled into nanomicelles, and were able to incorporate rifampicin (RF) into their hydrophobic inner cores. X-ray diffraction (XRD) patterns were applied to characterize the crystal structures of graft polymers and the effects of RF on micelle morphology. Empty and RF-loaded CS-g-PCL/FA nanomicelles underwent swelling and degradation in acidic pH conditions. Scanning electron microscopy, transmission electron microscopy, and dynamic light scattering revealed that the self-assembled, RF-loaded micelles were spherical, with an average size of 100-210nm. An in vitro study conducted at 37°C demonstrated that RF and FA release from micelles at pH 5.3 was much faster than that at pH 7.4. The RF and FA release was significantly accelerated by switching to an acidic pH, owing to swelling of the micelles at lower pH values caused by the rapid degradation of ester and amide bonds present in the micelles. Fluorescence micrographs revealed successful entry of the polymeric micelles into A549cell lines. Thus, graft polymeric micelles have promising potential for delivery of hydrophobic antitubercular drugs and may improve therapeutic approaches for tuberculosis.