SiRNA Delivery Using Dithiocarbamate-Anchored Oligonucleotides on Gold Nanorods

Jianxin Wang, Mini Thomas, Peng Lin, Ji Xin Cheng, Daniela E. Matei, Alexander Wei*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

23 Scopus citations

Abstract

We present a robust method for loading small interfering RNA (siRNA) duplexes onto the surfaces of gold nanorods (GNRs) at high density, using near-infrared laser irradiation to trigger their intracellular release with subsequent knockdown activity. Citrate-stabilized GNRs were first coated with oleylsulfobetaine, a zwitterionic amphiphile with low cytotoxicity, which produced stable dispersions at high ionic strength. Amine-modified siRNA duplexes were converted into dithiocarbamate (DTC) ligands and adsorbed onto GNR surfaces in a single incubation step at 0.5 M NaCl, simplifying the charge screening process. The DTC anchors were effective at minimizing premature siRNA desorption and release, a common but often overlooked problem in the use of gold nanoparticles as oligonucleotide carriers. The activity of GNR-siRNA complexes was evaluated systematically against an eGFP-producing ovarian cancer cell line (SKOV-3) using folate receptor-mediated uptake. Efficient knockdown was achieved by using a femtosecond-pulsed laser source to release DTC-anchored siRNA, with essentially no contributions from spontaneous (dark) RNA desorption. GNRs coated with thiol-anchored siRNA duplexes were less effective and also permitted low levels of knockdown activity without photothermal activation. Optimized siRNA delivery conditions were applied toward the targeted knockdown of transglutaminase 2, whose expression is associated with the progression of recurrent ovarian cancer, with a reduction in activity of >80% achieved after a single pulsed laser treatment.

Original languageEnglish (US)
Pages (from-to)443-453
Number of pages11
JournalBioconjugate Chemistry
Volume30
Issue number2
DOIs
StatePublished - Feb 20 2019

Funding

We gratefully acknowledge support from the Purdue University Center for Cancer Research (P30 CA023168), the Walther Cancer Institute, The U.S. Department of Veterans Affairs (I01 BX000792-06), and Mr. Dundas I. Flaherty. P.L. was supported by a Stephen R. Ash Fellowship at Purdue. We also thank Chi Zhang for assistance with fs-pulsed laser excitation, Ourania Andrisani for HepaRG cells, and Philip Low for folate-AF647.

ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering
  • Biomedical Engineering
  • Pharmacology
  • Pharmaceutical Science
  • Organic Chemistry

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