Preparation and atomic force microscopy of quadruplex DNA.

Area of Science:

• Molecular Biology
• Nanotechnology
• Biophysics

Background:

• Quadruplex DNA, specifically G-wire DNA, forms linear chains through self-assembly.
• Visualizing these nanoscale structures requires specialized techniques like atomic force microscopy (AFM).
• The precise conditions for G-wire DNA formation and imaging are complex and require detailed protocols.

Purpose of the Study:

• To provide comprehensive, step-by-step instructions for preparing and imaging linear chains of quadruplex DNA (G-wire DNA).
• To elucidate the critical factors influencing successful G-wire DNA self-assembly and AFM visualization.

Main Methods:

• Utilizing pure, concentrated guanine-rich oligonucleotide sequences (GROs) and monovalent cations in a growth buffer for self-assembly.
• Implementing a meticulous multi-step process for AFM imaging, including substrate preparation, G-wire adsorption, and controlled drying.
• Employing specific imaging probes and maintaining dry atmospheric conditions for optimal atomic force microscopy analysis.

Main Results:

• Detailed protocols are provided for each stage of G-wire DNA preparation and AFM imaging.
• The instructions cover critical parameters from G-wire concentration and substrate adsorption to probe selection and environmental control.

Conclusions:

• Successful atomic force microscopy imaging of individual G-wire DNA strands is achievable through careful adherence to detailed protocols.
• This chapter serves as a practical guide for researchers aiming to study the structure and properties of G-wire DNA.