Elucidating molecular oxygen adsorption in ZIF-8 through integrated experimental and computational studies

Area of Science:

• Materials Science
• Biomedical Engineering
• Chemical Engineering

Background:

• Controlled oxygen delivery is crucial for biomedical applications.
• Metal-organic frameworks (MOFs) offer tunable properties for gas adsorption and release.
• Zeolitic Imidazolate Framework-8 (ZIF-8) is a model MOF with potential biocompatibility.

Purpose of the Study:

• To investigate Zeolitic Imidazolate Framework-8 (ZIF-8) for molecular oxygen adsorption and release.
• To understand the mechanisms of oxygen confinement and release in MOFs under aqueous conditions.
• To evaluate the preliminary biocompatibility of ZIF-8 for biomedical applications.

Main Methods:

• Experimental oxygen adsorption/desorption measurements.
• Grand Canonical Monte Carlo (GCMC) and molecular dynamics simulations.
• Breakthrough experiments and kinetic modeling (Thomas, Yoon-Nelson, Adam-Bohart).
• Preliminary in vitro studies using A549 cells.

Main Results:

• ZIF-8 exhibited an oxygen uptake of approximately 0.9 mmol g^-1.
• Partial oxygen release was observed in deoxygenated PBS, dependent on concentration.
• Simulations revealed preferential adsorption sites and differences in pore-confined vs. surface-accessible oxygen.
• Adsorption kinetics were well-described by established models.
• Short-term in vitro studies indicated acceptable biological compatibility.

Conclusions:

• ZIF-8 serves as a biocompatible platform for studying oxygen adsorption and localized release mechanisms in MOFs.
• It is not suitable as a high-capacity systemic oxygen carrier but is valuable for proof-of-concept investigations.
• Further research can leverage ZIF-8 to develop MOF-based systems for controlled oxygen delivery in biomedical applications.