Extremely Large 3D Cages in Metal-Organic Frameworks for Nucleic Acid Extraction

Area of Science:

• Materials Science
• Nanotechnology
• Crystallography

Background:

• Three-dimensional (3D) cages in the mesopore range (2-50 nm) are crucial for biological applications but challenging to synthesize and characterize in crystalline form.
• Existing methods face limitations in creating large, well-defined 3D cages from molecular building blocks.

Purpose of the Study:

• To report the synthesis of exceptionally large 3D cages within metal-organic framework (MOF) crystals.
• To investigate the relationship between linker length, cage size, and crystallization efficiency.
• To demonstrate the application of these large MOF cages in biomolecule extraction.

Main Methods:

• Synthesis of MOF-929 and MOF-939 using specific organic linkers.
• Characterization of cage structures and spatial arrangements using X-ray diffraction and transmission electron microscopy.
• Evaluation of cage performance in extracting long nucleic acids from aqueous solutions.

Main Results:

• Successfully synthesized MOF crystals (MOF-929 and MOF-939) containing extremely large 3D cages with internal sizes of 6.9, 8.5, 9.3, and 11.4 nm.
• Demonstrated a high efficiency in cage expansion, with a 0.45 nm linker length increase yielding a 2.9 nm cage size increase.
• Achieved complete extraction of long nucleic acids, including total RNA and plasmid DNA, from aqueous solutions using the synthesized MOF cages.

Conclusions:

• The study advances the size limitations for constructing 3D cages from molecular components within MOFs.
• The findings highlight the critical role of cage expansion efficiency in maximizing cage size.
• The developed extremely large 3D MOF cages show significant potential for applications in biomolecule separation and purification.