Pegylated Gold Nanoparticles Conjugated with siRNA: Complexes Formation and Cytotoxicity

Abstract

Drug delivery systems such as dendrimers, liposomes, polymers or gold/silver nanoparticles could be used to advance modern medicine. One significant pharmacological problem is crossing biological barriers by commonly used drugs, e.g., in the treatment of neurodegenerative diseases, which have a problem of the blood-brain barrier (BBB) restricting drug delivery. Numerous studies have been conducted to find appropriate drug carriers that are safe, biocompatible and efficient. In this work, we evaluate pegylated gold nanoparticles AuNP14a and AuNP14b after their conjugation with therapeutic siRNA directed against APOE4. This genetic risk factor remains the strongest predictor for late-onset Alzheimer’s disease. The study aimed to assess the biophysical properties of AuNPs/siAPOE complexes and to check their biological safety on healthy cells using human brain endothelial cells (HBEC-5i). Techniques such as fluorescence polarization, circular dichroism, dynamic light scattering, ζ-potential measurements and gel retardation assay showed that AuNPs form stable complexes with siRNA. Subsequently, cytotoxicity assays proved the biological safety of formed conjugates. Obtained results enabled us to find effective concentrations of AuNPs when complexes are formed and non-toxic for healthy cells. One of the studied nanoparticles, AuNP14b complexed with siRNA, displayed lower cytotoxicity (MTT assay, cells viability −74.8 ± 3.1%) than free nanoparticles (44.7 ± 3.6%). This may be promising for further investigations in nucleic acid delivery and could have practical use in treating neurodegenerative diseases.

Assessing the toxicity of one-step-synthesized PEG-coated gold nanoparticles: in vitro and in vivo studies

“…AuNPs find significant applications in nanomedicine, particularly in biosensor labeling, bioimaging, drug delivery systems, and phototherapeutic roles. (12,13,15,21) Recent research have focused on the development of affordable biocompatible NPs that can be employed in clinical trials. (7) In this scenario, AuNPs stand out because of their high biocompatibility and ability to be used in different applications.…”

“…(10) In addition to being stable, simple to manufacture, controllable in size, and straightforward for surface functionalization, these NPs also present strongly enhanced optical properties and high biocompatibility for in vivo studies. (11) The utilization of AuNPs has thus distinguished itself in a number of applications, serving as promising carriers for different biomolecules, such as drugs, therapeutic proteins, DNA, or RNA, (12,13) in addition to acting as phototherapeutic and tumor detection agents. (13)(14)(15)(16) One of the more feasible options for enhancing the medical properties of AuNPs is PEGylation, which involves coating NPs with PEG, a biopolymer that is affordable, versatile, and FDA-cleared.…”

“…Moreover, PEGlyation allows for easier passage of NPs through different biological barriers, such as the blood-brain barrier. (12,18) One current challenge in nanomedicine is the development of simple, rapid, biocompatible, and affordable PEGylation methods. (10) The use of unmodified PEG as a reducing and stabilizing agent for AuNPs has been shown to be a viable alternative because it is capable of synthesizing stable and lowpolydispersity NPs via a controllable and reproducible one-step synthesis process.…”

Impacts of polyethylene glycol (PEG) dispersity on protein adsorption, pharmacokinetics, and biodistribution of PEGylated gold nanoparticles

“… 20 For instance, doxorubicin can be efficiently attached to PEG-coated AuNPs for targeted cancer cell treatment. 21 Okła E. 22 and colleagues used PEG-AuNPs (AuNP14a and AuNP14b) coupled with therapeutic siRNA targeting the Alzheimer's disease gene (APOE4). The conjugated complexes exhibited low cytotoxicity, providing a foundation for further research into the use of gold nanoparticles in nucleic acid delivery.…”

Special Issue “Latest Advances in Nanomedicine Strategies for Different Diseases”

“…Elżbieta Okla et al harnessed this ability of AuNPs and modified them through Polyethylene Gylcol (PEG)ylation to improve the central nervous system (CNS) delivery of a AuNP/APOE small interfering Ribonucleic Acid (siRNA)formulation for Alzheimer’s disease treatment. Additionally, they showed that these AuNPs/siAPOE4 complexes demonstrated significantly lower cytotoxicity in human brain endothelial cells than free nanoparticles, demonstrating the safety and tolerability of this novel nanotherapeutic formulation [ 9 ].…”