**Conflict of interest**

*Antisense Therapy*

silencing [53].

*3.2.2 Natural polymers*

the formation of polyplex [55].

**3.3 Lipid-polymer hybrid nanoparticles**

into the cell at twice the rate.

In a study done by Patil and Panyam [51], siRNA encapsulation studies were performed in PLGA nanoparticles. These nanoparticles were prepared by the solvent evaporation method. In this method, a cationic polymer, PEI, was added to the PLGA matrix, and ultimately it has been reported that nanoparticles can penetrate

Furthermore, cationic polymers with high charge densities have "proton sponge"

properties that stimulate escape from endosomes and protect genetic materials from degradation. For example, PEI, by pulling and sustaining a significant amount of protons, induces osmotic swelling and rupture of endosomes, causing the genetic material to be released from the nanoparticles in the cytoplasm and thus preventing

In another study, the hydrogel scaffold based on polyamidoamine (PAMAM) dendrimer cross-linked with dextran aldehyde was prepared to improve the stability of the nanoparticle. These nanoparticle systems were found to be effective for gene

Many polysaccharides in natural Polymer structure are used for siRNA. Polysaccharides are generally biocompatible polymers. The main advantage is the presence of different functional groups (i.e., carboxyl, hydroxyl, amine) which enable functionalization to obtain structural heterogeneity and copolymers [54]. The most commonly used polysaccharides for siRNA administration include chitosan, which contains both biodegradable, biocompatible, low-cost, low cytotoxicity hydroxyl and amines. The presence of primary amino groups (pKa ≈ 6) makes the chitosan a polycation that promotes the association with nucleic acids and also

In order to increase the solubility of chitosan, various modifications have been done and water-soluble chitololigosaccharides have been obtained. These chitololi-

Collagen is another biologically compatible and safe natural polymer and is a suitable carrier for drug delivery. In a study performed by Peng et al., localized and sustained release of siRNA-loaded collagen formulations were prepared for use

Lipid-polymer hybrid nanoparticles (LPNs) were developed to eliminate the disadvantages of polymeric and lipid-based nanoparticles. The precious properties of LPNs containing polymer cores and lipid shells carry the complementary properties of both materials. In a study on the administration of LPNs in cancer treatment, the lipid/rPAA-Chol polymer hybrid nanoparticles were modified with PEG and T7 peptide; tumor has

In another study, LPNs were used for the antitumoral effect in the pancreatic

In recent years, siRNA has been widely used as a promising therapeutic phenomenon to many pathological conditions. Progress has been made in researching target

been shown to be largely inhibited without activating the immune system [58].

tumor model in combination with hypoxia-inducible factor 1α (HIF1alpha) targeted siRNA and gemitabicin. This prepared LPN complex showed an excellent

ability to inhibit tumor metastasis in an orthotopic tumor model [59].

gosaccharides were used for delivery of the siRNA [35, 56].

in vivo gastric cancer, and positive results were obtained [57].

the transport to lysosomes and degradation of genetic material [52].

**86**

**4. Conclusion**

The authors report no conflicts of interest. The authors alone are responsible for the content of and writing of this article.
