Key points are not available for this paper at this time.
Embedding depolymerizing enzymes in biodegradable plastics provides a promising strategy for developing self-biodegradable materials that degrade independently of external biological stimuli. However, the scalable melt processing of such materials remains fundamentally constrained by the intrinsic thermal fragility of enzymes. Here, we report a dual thermal protection mechanism that integrates molecular confinement and thermal insulation within a hydrophilic metal azolate framework (MAF-7) to extend enzyme stability to the melt-processing regime of hydrophobic polyesters. Proteinase K (pro K) was encapsulated within MAF-7 via a one-pot synthesis, where the mesoporous framework confined the enzyme and created a thermally insulated microenvironment. This protection preserved the secondary and tertiary structures of the enzyme, enabling pro K@MAF-7 to retain 70% of its catalytic activity after heating at 170 °C for 10 min. The unfilled pores of MAF-7 within the hydrophobic polylactide (PLA) melt ensured effective protection, and the resulting pro K@MAF-7/PLA composites processed by extrusion and hot pressing at 170 °C exhibited markedly accelerated hydrolysis, showing 70% weight loss after 84 days and nearly complete degradation in an aqueous buffer. The same protective mechanism was also applicable to lipase PS. This work establishes a versatile strategy for creating melt-processable, self-biodegradable plastics through metal-organic framework (MOF)-assisted enzyme confinement and molecular-scale thermal management.
Ma et al. (Mon,) studied this question.