Resolving DNA Origami Structural Integrity and Pharmacokinetics in Vivo

Why It Matters

Accurate in‑vivo integrity measurement enables reliable dosing, safety assessment, and regulatory approval of DNA‑nanotherapeutics, accelerating their clinical translation.

Key Takeaways

• PLASTIQ quantifies intact DNA origami via ligation of staple pairs
• Detects single-helix integrity from 1 µl blood sample
• PEGylation modestly extends circulation half‑life after i.p. injection
• Fluorescence tracking overestimates persistence of degraded origami
• Regional stability differences observed within barrel-shaped origami

Pulse Analysis

DNA origami promises unprecedented control over nanoscale drug delivery, yet its clinical promise has been hampered by a lack of reliable in‑vivo integrity assays. Conventional fluorescence labeling or scaffold‑targeted qPCR can’t distinguish intact nanostructures from degraded fragments, leading to misleading pharmacokinetic data. PLASTIQ fills this gap by exploiting proximity ligation between adjacent staples; only when the scaffold holds the pair together does ligation occur, producing a quantifiable signal. This label‑free approach works with both wireframe and lattice designs, tolerates PEGylation and UV cross‑linking, and reaches femtomolar sensitivity from a single microliter of blood, dramatically reducing animal usage and sampling constraints.

The authors validated PLASTIQ in vitro, confirming that ligation signals disappear upon heat denaturation while traditional qPCR remains positive. In mouse models, PLASTIQ tracked the rapid disappearance of bare DNA rods after intravenous injection and demonstrated that PEG‑coated rods retain detectable integrity slightly longer, especially after intraperitoneal delivery. By contrast, fluorescence‑based tracking showed persistent signals even when PLASTIQ indicated complete degradation, underscoring the risk of over‑estimating therapeutic exposure. Moreover, the assay resolved sub‑origami stability, revealing that interior surfaces of a barrel‑shaped construct resist nuclease attack better than exposed faces, information critical for rational design of protective coatings and payload placement.

For the broader nanomedicine field, PLASTIQ offers a quantitative, regulatory‑friendly metric that can be integrated into preclinical pipelines. Accurate half‑life and biodistribution data will streamline dose‑finding studies, improve safety margins, and support the filing of IND applications for DNA‑based therapeutics and vaccines. Future extensions could adapt the workflow for intracellular compartments or tissue biopsies, enabling comprehensive pharmacodynamics profiling. As DNA nanostructures move toward commercial manufacturing, tools like PLASTIQ will be essential for quality control, batch‑to‑batch consistency, and ultimately, patient confidence in these next‑generation medicines.