Advances in the construction and biological applications of DNA condensates

Intracellular biomolecular condensates are membraneless liquid droplets formed by liquid-liquid phase separation (LLPS), which play essential roles in transcriptional control, stress responses, and cellular signaling. Inspired by these natural systems, DNA has emerged as the preferred molecule for constructing artificial condensates due to its sequence programmability, diverse interaction modes, and ease of chemical modification. This review provides a comprehensive overview of strategies for constructing DNA condensates through LLPS, including sequence-driven self-assembly, polymer- or protein-mediated coacervation, and precise environmental tuning such as DNA concentration, ionic strength, pH, and temperature. We highlight their multi-stimuli responsiveness and ability to create programmable biochemical microenvironments, which underpin notable progress in mimicking membraneless organelles, biosensing, cell regulation, and drug delivery. Finally, we discuss prevailing challenges, including limited spatiotemporal control, nuclease degradation, and immunogenicity, which must be addressed to advance their translation into living systems. Future progress is anticipated to arise from intelligent multicomponent systems, integration with optogenetics and single-molecule techniques, and machine learning-aided sequence design, ultimately paving the way for adaptive "active DNA materials" with far-reaching implications for synthetic biology and precision medicine.