Biocompatible Microscale DNA Hydrogels with Programmable Swelling and Sequence-Specific Dissolution

Stimulus-responsive DNA-hydrogels with swelling capabilities are a promising class of materials for biomedical applications such as drug delivery and biosensing. However, translation of these systems to microscale applications requires fabrication methods that are both biocompatible and material-efficient, while enabling precise control over stimulus-induced swelling and its impact on molecular transport. Here, we present a biocompatible fabrication and characterization platform for micron-scale DNA-hydrogels (microSDs) with tunable isotropic swelling and dissolving properties. Our approach includes a biocompatible, material-efficient fabrication workflow that conserves valuable DNA reagents by minimizing dead volume and process loss. We then demonstrated modular control over isotropic swelling in microSDs, achieving up to a two-fold size increase through programmable DNA design parameters. We further established a quantitative workflow to extract effective diffusivity and characterize swelling-induced modulation of molecular transport in spherical microSDs using YOYO-1. Finally, we demonstrate the dissolution of microSDs using a DNA strand and find that dissolution kinetics are governed by the rates of coupled strand-displacement reactions and diffusive transport. This platform enables programmable swelling and structural disassembly in microSDs. Swelling-induced network expansion further allows predictable modulation of molecular transport, thereby expanding the potential of microSDs for applications such as triggered drug delivery, multiplexed biosensing, and single-cell assays.