Exploring the Subcellular Localization and Degradation of Spherical Nucleic Acids Using Fluorescence Lifetime Imaging...

Area of Science:

• Nanotechnology
• Molecular Biology
• Biophysics

Background:

• Spherical nucleic acids (SNAs) are promising for diagnostics and therapeutics.
• Their intracellular trafficking and stability are poorly understood, with conflicting reports.
• Previous studies often relied on indirect fluorescence measurements prone to artifacts.

Purpose of the Study:

• To investigate the intracellular fate of SNAs using advanced microscopy.
• To characterize the early stages of SNA degradation within cells.
• To resolve conflicting literature claims regarding SNA stability and endosomal entrapment.

Main Methods:

• Utilized fluorescence lifetime imaging microscopy (FLIM) for enhanced SNA tracking.
• Investigated monothiol and dithiol anchored gold nanoparticle-SNAs.
• Examined phosphorothioate backbone-modified SNAs.
• Employed model cell lines to study SNA degradation dynamics.

Main Results:

• FLIM provided detailed insights into SNA intracellular trafficking.
• Internalized SNAs lost up to 20% of their nucleic acids within 24 hours.
• Degradation rates were influenced by DNase II activity and thiol-displacement.

Conclusions:

• FLIM is a valuable tool for elucidating SNA intracellular fate.
• SNAs undergo degradation within cells, challenging previous assumptions of stability.
• Understanding SNA degradation is crucial for optimizing their therapeutic and diagnostic applications.