Noncovalent Cluster Packing Enables Ultrastable Glasses for Preservation and Delivery of Labile Biomolecules.

The properties of molecular glasses are governed by a thermodynamic-kinetic coupling described by the Adam-Gibbs theory. This relationship enforces a persistent trade-off: glasses with low glass transition temperatures, essential for gentle processing, are inherently unstable and prone to rapid crystallization. Here, we report a noncovalent glass system that, defies this paradigm, achieving an exceptional crystallization barrier exceeding 653.2 kJ mol-1, while maintaining a moderate glass transition temperature below 332.3 K. This anomalous decoupling originates from a "noncovalent cluster packing" architecture where internally rigid, hydrogen-bonded nanoclusters are loosely interconnected by weak interactions. This distinct topology effectively isolates local structural rigidity from global relaxation, creating a landscape that, suppresses nucleation pathways. We demonstrate the practical utility of this principle through the robust room-temperature preservation and delivery of labile biomolecules. By challenging conventional theoretical constraints, this work establishes a general design strategy for creating ultrastable yet functionally versatile amorphous materials.