Exploring Biliverdin's Molecular Interactions with Cu- and Fe-Based MOFs: A Unified In Vitro Study with Photoacoustic...

Area of Science:

• Materials Science
• Biomaterials Engineering
• Nanotechnology

Background:

• Metal-organic frameworks (MOFs) are advanced porous materials with tunable structures.
• MOFs show potential for stabilizing sensitive biomolecules.
• Biliverdin (BVD) is a photoacoustic and fluorescent agent with biomedical applications.

Purpose of the Study:

• To investigate the immobilization of biliverdin (BVD) within and on metal-organic frameworks (MOFs).
• To evaluate the impact of MOF structure and interactions on BVD's spectral properties and loading.
• To understand the role of MOF pore versus surface interactions in BVD encapsulation and release.

Main Methods:

• Immobilization of BVD in NH2-MIL-101 (Fe) (FeMOFs) and on CuBTC (CuMOFs).
• Characterization using fluorescence and photoacoustic (PA) spectroscopy.
• Density Functional Theory (DFT) simulations to analyze spectral interactions and energy gaps.

Main Results:

• MOFs enhanced BVD fluorescence emission and quenched its PA intensity.
• Spectral changes were attributed to BVD-MOF pore/surface interactions and altered HOMO-LUMO energy gaps.
• FeMOFs facilitated greater BVD encapsulation, while CuMOFs showed primarily surface interactions.

Conclusions:

• MOF internal structure significantly influences BVD loading efficiency.
• Surface versus pore interactions play distinct roles in BVD encapsulation and release dynamics.
• Consideration of MOF structure, surface chemistry, and electronic interactions is crucial for effective biomolecule loading.