(141h) Self-Organization of Iron Sulfide Nanoparticles into Multi-Compartment Supraparticles

Emine S. Turali-Emre^1,5, Ahmet E. Emre^1,5, Luis Rivera-Rivera^2,5, Usha Kadiyala^4,6, Thi Vo^2,6, Scott VanEpps^4,5,6, Sharon C. Glotzer^2,3,5, and Nicholas A. Kotov^1,2,3,5,6*

¹Biomedical Engineering Department, University of Michigan, Ann Arbor, USA;

²Chemical Engineering Department, University of Michigan, Ann Arbor, USA;

³Materials Science and Engineering Department, University of Michigan Ann Arbor, USA;

⁴Department of Emergency Medicine, University of Michigan, Ann Arbor, Michigan 48109, United States

⁵Macromolecular Science and Engineering Department, University of Michigan, Ann Arbor, USA;

⁶Biointerfaces Institute University of Michigan; University of Michigan; Ann Arbor, USA

Gene and gene editing therapies have been widely investigated for treatment of inherited or acquired genetic diseases. Efficient delivery of therapeutic agents has become a significant barrier in clinical applications due to the toxicity and instability of the vectors in the complex intracellular environment. Among non-viral vectors, inorganic nanoparticles (NPs) have become a popular strategy for nucleic acid delivery. Even though, NPs can condense the nucleic acids, the nanoshell geometry of viruses is advantageous for the gene/gene editing therapies cargo protection. Therefore, we synthetized iron-based inorganic nanoparticles which self-assemble into supraparticles with nanoshell geometry. We synthetized L-cysteine stabilized iron sulfide NPs in aqueous media to eliminate toxic reagents during synthesis. Careful selection of the reaction conditions such as precursor concentrations, pH level and reaction time allowed us to find a condition where iron sulfide NPs self-assembly into virus-like supraparticles. Transmission electron microscopy (TEM), TEM tomography and dynamic light scattering (DLS) were used to characterize these supraparticles for size, shape, and charge. Our results indicate that virus-like supraparticles contain continuous compartments, are positively charged (25±7.2 mV) and 74±21 nm in diameter. We loaded deoxyribonucleic acid (DNA) in the compartments during the formation of supraparticles. We tested these complexes in circular dichroism, UV-Vis spectroscopy, electrophoretic mobility shift and protection assays to confirm the encapsulation of DNA in the compartments. Since iron sulfide is a natural material, it presumably has low cytotoxicity and high biocompatibility. Supraparticles can condense DNA, protect it against degradation, penetrate through cellular membranes and facilitate endolysosomal escape in gene therapy. Therefore, development of these virus-like particles can be used as an effective cargo delivery tool for gene and gene editing therapies such as CRISPR.