Methods of the Synthesis of Silicon-Containing Nanoparticles Intended for Nucleic Acid Delivery

Effect of modification of siRNA molecules delivered with aminopropylsilanol nanoparticles on suppression of A/H5N1 virus in cell culture

The application of siRNAs as antiviral agents is limited by several obstacles including their poor penetration into cells and instability in biological media. To overcome these problems, we used non-agglomerated aminopropylsilanol nanoparticles (NP) to deliver siRNA into cells. All studied siRNAs had identical nucleoside sequences comprising phosphodiester or phosphorothioate (PS) internucleotide groups and the 2'-OMe and/or 2'-F groups in nucleoside units at different positions of RNA. The siRNA molecules were attached to NP, thus forming the NP-siRNA nanocomplexes. We studied the effect of siRNA modification in the nanocomplexes on suppressing the highly pathogenic influenza A/H5N1 virus replication. The results demonstrated that all siRNA-containing nanocomplexes inhibited the replication of the A/H5N1 virus by 1-3 orders of magnitude. The nanocomplexes containing partially modified siRNAs exhibited the most pronounced inhibition with an efficacy of 900-fold. This result was achieved by using siRNA consisting of the canonical 19-bp RNA duplex with the 3'-dTdT dangling ends, with the antisense strand in this duplex being protected from endonucleases (one UMeA site within the strand). The additional modifications of siRNA reduce their antiviral activity. Promising sense strands for loading into the RISC complex are likely to be phosphodiester sequences that contain dTdT at the 3' end (such as S4) to be protected against exonucleases. The sense strands of this type can probably be the most suitable for designing siRNAs as therapeutic agents. The proposed NP-siRNA nanocomplexes that consisted of low toxic and non-agglomerated aminopropylsilanol nanoparticles and siRNA molecules could be hopeful agents for gene silencing.

Nucleic acid drugs: recent progress and future perspectives

High efficacy, selectivity and cellular targeting of therapeutic agents has been an active area of investigation for decades. Currently, most clinically approved therapeutics are small molecules or protein/antibody biologics. Targeted action of small molecule drugs remains a challenge in medicine. In addition, many diseases are considered 'undruggable' using standard biomacromolecules. Many of these challenges however, can be addressed using nucleic therapeutics. Nucleic acid drugs (NADs) are a new generation of gene-editing modalities characterized by their high efficiency and rapid development, which have become an active research topic in new drug development field. However, many factors, including their low stability, short half-life, high immunogenicity, tissue targeting, cellular uptake, and endosomal escape, hamper the delivery and clinical application of NADs. Scientists have used chemical modification techniques to improve the physicochemical properties of NADs. In contrast, modified NADs typically require carriers to enter target cells and reach specific intracellular locations. Multiple delivery approaches have been developed to effectively improve intracellular delivery and the in vivo bioavailability of NADs. Several NADs have entered the clinical trial recently, and some have been approved for therapeutic use in different fields. This review summarizes NADs development and evolution and introduces NADs classifications and general delivery strategies, highlighting their success in clinical applications. Additionally, this review discusses the limitations and potential future applications of NADs as gene therapy candidates.

Advances in Hybrid Vesicular-based Drug Delivery Systems: Improved Biocompatibility, Targeting, Therapeutic Efficacy and Pharmacokinetics of Anticancer Drugs

Anticancer drugs and diagnostics can be transported in nanoscale vesicles that provide a flexible platform. A hybrid nanoparticle, a nano assembly made up of many types of nanostructures, has the greatest potential to perform these two activities simultaneously. Nanomedicine has shown the promise of vesicular carriers based on lipopolymersomes, lipid peptides, and metallic hybrid nano-vesicle systems. However, there are significant limitations that hinder the clinical implementation of these systems at the commercial scale, such as low productivity, high energy consumption, expensive setup, long process durations, and the current cancer therapies described in this article. Combinatorial hybrid systems can be used to reduce the above limitations. A greater therapeutic index and improved clinical results are possible with hybrid nanovesicular systems, which integrate the benefits of many carriers into a single structure. Due to their unique properties, cell-based drug delivery systems have shown tremendous benefits in the treatment of cancer. Nanoparticles (NPs) can benefit significantly from the properties of erythrocytes and platelets, which are part of the circulatory cells and circulate for a long time. Due to their unique physicochemical properties, nanomaterials play an essential role in cell-based drug delivery. Combining the advantages of different nanomaterials and cell types gives the resulting delivery systems a wide range of desirable properties. NPs are nextgeneration core-shell nanostructures that combine a lipid shell with a polymer core. The fabrication of lipid-polymer hybrid NPs has recently undergone a fundamental shift, moving from a two-step to a one-step technique based on the joint self-assembly of polymers and lipids. Oncologists are particularly interested in this method as a combinatorial drug delivery platform because of its two-in-one structure. This article addresses various preparative methods for the preparation of hybrid nano-vesicular systems. It also discusses the cellular mechanism of hybrid nano-vesicular systems and describes the thorough knowledge of various hybrid vesicular systems.

Silica-Based Gene Delivery Systems: From Design to Therapeutic Applications

Advances in gene therapy have been foreshadowing its potential for the treatment of a vast range of diseases involving genetic malfunctioning. However, its therapeutic efficiency and successful outcome are highly dependent on the development of the ideal gene delivery system. On that matter, silica-based vectors have diverted some attention from viral and other types of non-viral vectors due to their increased safety, easily modifiable structure and surface, high stability, and cost-effectiveness. The versatility of silane chemistry and the combination of silica with other materials, such as polymers, lipids, or inorganic particles, has resulted in the development of carriers with great loading capacities, ability to effectively protect and bind genetic material, targeted delivery, and stimuli-responsive release of cargos. Promising results have been obtained both in vitro and in vivo using these nanosystems as multifunctional platforms in different potential therapeutic areas, such as cancer or brain therapies, sometimes combined with imaging functions. Herein, the current advances in silica-based systems designed for gene therapy are reviewed, including their main properties, fabrication methods, surface modifications, and potential therapeutic applications.