[Condensed DNA particles formed in PCR with plasmid DNA: electron microscopy study]

Area of Science:

• Molecular Biology
• Nanotechnology
• Biophysics

Context:

• Polymerase Chain Reaction (PCR) is a fundamental technique for amplifying DNA.
• The physical forms and self-assembly of DNA under various conditions are of significant scientific interest.
• Understanding DNA nanoparticle formation is crucial for developing novel biotechnological applications.

Purpose:

• To characterize the morphology and structures of DNA microparticles generated via PCR using electron microscopy.
• To investigate the influence of asymmetric PCR on the formation of specific DNA nanostructures.
• To analyze the structural changes in DNA microparticles upon thermal treatment.

Summary:

• Electron microscopy identified two types of DNA microspheres (smooth and thorny), 3D net-like structures, nanodiscs, nanowires, and other nanoparticles produced during PCR.
• Asymmetric PCR conditions led to a notable increase in the abundance of net-like structures and nanodiscs.
• Heating DNA microparticle suspensions caused partial melting, revealing internal ultrastructure and promoting nanowire formation, suggesting dynamic self-assembly mechanisms.

Impact:

• Provides novel insights into the physical states and self-assembly of DNA beyond simple amplification.
• Highlights the potential for controlling DNA nanostructure formation through PCR conditions.
• Offers a foundation for exploring DNA micro/nanoparticles in fields like drug delivery, diagnostics, and materials science.