Dual-Functional Amino-MOF with Enhanced Ice Suppression and Intrinsic Photothermal Activity for High-Performance Oocyte Cryopreservation

The current vitrification-based oocyte cryopreservation relies on inherently cytotoxic high-concentration cryoprotective agents (CPAs), leading to suboptimal post-thaw survival rates and diminished developmental competence. To address this, we developed a series of highly biocompatible amino-functionalized iron-based metal-organic frameworks (Fe-MOFs) via a facile hydrothermal method to synergistically suppress ice crystallization and minimize the reliance on toxic CPAs. Among the synthesized materials, 2NH₂-MIL88(Fe) demonstrated exceptional ice-inhibition performance, reducing ice crystal size to 16.78% of that observed in pure water, significantly outperforming its nonaminated counterpart MIL88(Fe) and monoaminated counterpart NH₂-MIL88(Fe). Notably, 2NH₂-MIL88(Fe) exhibited an unprecedented intrinsic photothermal response without requiring photosensitizer modification, achieving rapid temperature elevation from 25 to 86.6 °C under 808 nm laser irradiation (1 W/cm², 1 min). When applied to mouse oocyte cryopreservation, this dual-functional amino-MOF enabled complete elimination of dimethyl sulfoxide (DMSO) from CPAs while maintaining an exceptional post-thaw survival rate of 95.1%. Our findings establish a dual correlation between amino group density and both ice-growth suppression efficiency and photothermal performance, revealing a synergistic mechanism for mouse oocyte cryopreservation enhancement. This structure-function relationship provides critical insights for the rational design of next-generation nano-CPAs.