Phase transitions in DNA-linked nanoparticle assemblies: a decorated-lattice model.

Area of Science:

• Colloid and Interface Science
• Biophysics
• Materials Science

Background:

• DNA-linked colloidal systems exhibit complex phase behavior influenced by particle interactions.
• Understanding these interactions is crucial for designing novel self-assembling materials.

Purpose of the Study:

• To explore the phase behavior of two distinct DNA-linked colloidal mixtures using decorated-lattice models.
• To investigate the influence of temperature, nanoparticle functionalization, and DNA strand number on assembly dissolution.

Main Methods:

• Utilized decorated-lattice models derived from spin-n Ising models.
• Analyzed temperature and activity-dependent effective interactions.
• Predicted dissolution profiles as a function of temperature and DNA strand number (M).

Main Results:

• Model predictions align qualitatively with experimental observations of dissolution profiles.
• Dissolution temperature increases with M below a concentration threshold, but decreases above it.
• Linker-mediated interactions in Aa-Ab mixtures favor ordered phases over disordered aggregates.

Conclusions:

• The study explains contrasting dissolution temperature trends in Aab and Aa-Ab mixtures based on nanoparticle functionalization.
• Enhanced colloidal network ordering increases the stability and dissolution temperature of DNA-linked assemblies.
• The findings provide insights into the design and behavior of DNA-programmable colloidal systems.