Ultramild One-Step Encapsulating Method as a Modular Strategy for Protecting Humidity-Susceptible Metal-Organic Frameworks Achieving Tunable Drug Release Profiles

Metal-organic frameworks (MOFs), composed of metal ions or clusters and organic ligands, have emerged as a new class of porous materials. However, water instability of many MOFs has impeded their further applications. Herein, an ultramild one-step encapsulating method has been developed by incorporating γ-cyclodextrin-based MOFs (CD-MOFs) into hydrophobic ethylcellulose to fabricate composite microparticles for ideal hydrolytic stability. The whole process can be completed at ambient temperature by the novel ultrafine particle processing system in several minutes without any purification or drying steps. The composite microparticles well retained their morphology and crystal structure of CD-MOFs even after being exposed to extreme humid environment for 30 d. The composite microparticles were further exploited for drug delivery. The composite microparticles not only exhibited sustained and tunable pH-dependent drug release profiles in simulated physiological conditions but also reduced cell toxicity compared with drug-loaded CD-MOFs, which demonstrated that the composite microparticles were promising as drug carriers. In summary, this study developed a modular strategy for protecting humidity-susceptible MOFs with controlled release profiles, which is expected to open up a new avenue to expand their applications in the biomedical field.