DNA origami nanoparticles (DONs) offer a powerful platform for interfacing with biological systems due to their precise structural programmability and molecular addressability. However, their performance is highly dependent on their stability and interaction behavior within biological milieus, where the characteristic nuclease activity and ionic conditions can rapidly compromise their structural and colloidal properties. To address these challenges, stabilizing coatings such as oligolysine-poly(ethylene glycol) (PEG) have emerged as a widely adopted solution, providing a protective layer that shields DONs from denaturation and enzymatic degradation while mitigating aggregation. Although effective, these coatings fundamentally reshape the biointerface of DONs, altering their biomolecular interactions, cellular uptake, and functional capacity in ways that remain only partially understood. This thesis systematically maps the operative space of oligolysine-PEG-biostabilized DONs, identifying key parameters that govern their stability, biomolecular interfacing, and functional adaptability.

In Chapter 2, we investigate the role of PEG length in defining DON colloidal stability and structural resilience across diverse environments, including both physiological and supra-physiological conditions. We identify key aspects that govern aggregation and degradation susceptibility while establishing useful operative thresholds for the often-overlooked 1kPEG variant, thereby expanding and refining the available design space for DON stabilization. Chapter 3 extends this mapping effort to the protein corona, demonstrating that polymer coatings actively modulate protein adsorption rather than acting as passive, defensive barriers. Through proteomic characterization, we establish correlations between coating architecture and protein recruitment and exploit these interactions to influence macrophage uptake, illustrating how surface modifications shape the biological identity of DONs. Chapter 4 introduces a dynamic component to these coatings by incorporating reductively cleavable disulfide linkers within the oligolysine backbone. We demonstrate that these stimuli-responsive coatings enable controlled decomplexation in intracellular-like reductive environments, preserving DON protection in serum while facilitating functional restoration upon reduction.

This work positions oligolysine-PEG coatings as versatile modulators of DON interactions at the biointerface, bridging fundamental studies on stabilization with applied insights into biomolecular interactions and stimuli-responsiveness. By mapping their operative space, we establish a comprehensive framework for tailoring and engineering polymer-biostabilized DONs, providing new guidelines to refine their function and broaden their applicability in complex biological environments.