Synthesis, Characterization and Biocompatibility of a Multifunctional Gold Nanoparticle System for the Delivery of Single-Stranded RNA to Lymphocytes

Abstract

The use of RNA macromolecules as therapeutic agents for HIV and other infectious diseases is promising but limited by suboptimal delivery to the target site. With HIV infection, this is particularly challenging since lymphocytes are particularly difficult to transfect. This paper describes an innovative strategy for the intracellular delivery of a novel single-stranded RNA (oligoribonucleotide) with putative anti-HIV activity. This strategy is based on a PEGylated gold nanoparticle scaffold covalently linked to the thiol-modified oligoribonucleotide via a cleavable N-succinimidyl 3-(2-pyridyldithio) propionate (SPDP) linker molecule. The nanoparticle was then coated with a cationic polymer (polyethyleneimine) to facilitate cell entry and endosomal escape. A synthetic anti-CD4 cyclic targeting peptide was attached to the polyethyleneimine-coated nanoparticle via an SPDP linker molecule, in an attempt to enhance uptake and selectivity. Synthesis, characterization, SPDP and RNA loading, cytotoxicity and antiviral activity of the nanoparticle are described. Approximately 45 000 strands of RNA were taken up per lymphocyte. Uptake was limited by relatively inefficient loading of RNA onto the gold nanoparticle surface (1 strand per 4.8 nm 2 of nanoparticle surface area) and significant aggregation of the nanoparticle in physiological solutions. No antiviral activity was demonstrated, possibly due to insufficient intracytoplasmic delivery of the RNA.

Recent advances on therapeutic potentials of gold and silver nanobiomaterials for human viral diseases

“…Unfortunately, so much waste is generated in addition to the required sophisticated resources. These limit their use, especially for certain biomedical applications [ 7 ].…”

“…Despite these qualities, the chemical methods may not be without some disadvantages such as environmental pollution due to the toxic nature of the chemicals that might have been employed. Hence, some of the NPs from this route may not be suitable for certain biomedical applications [ 7 ].…”

“…Size, polydispersity, concentration and ZP of the NPs were tested for at the end of each synthesis step. The characterization results indicated mean core diameters of the NPs between 30 – 40 nm, λ max 527 – 530 nm and ZPs in the range of -21.4 and 13.5 mV [ 7 ]. Malik et al reportedly prepared Efaverinz and AuNPs loaded niosomes by employing the reverse phase evaporation technique.…”

“…8 ). The modified NPs demonstrate a nanotechnology-dependent delivery, although, no antiviral activity was recorded when subjected to MTT cytotoxicity assay and antiviral assay against HIV suggestively due to inadequate intracytoplasmic delivery of the RNA molecules [ 7 ]. An improved delivery of stavudine, an antiretroviral medication was demonstrated through Au nanocarriers.…”

“…Till this moment, scientific efforts are being made by researchers to find a vaccine and effective treatment options for the infection with limited success [ 5 ]. Generally, despite the enormous efficacious potentials of some topical virucidal agents, toxicity, the resistance of the pathogens and suboptimal delivery of the agents to target sites contributively limit their real-life clinical successes [ 6 , 7 ]. These make the treatment of viral diseases remain a challenging task.…”