Transition Metal-Mediated DNA Adsorption on Polydopamine Nanoparticles

Area of Science:

• Materials Science
• Biotechnology
• Surface Chemistry

Background:

• Polydopamine (PDA) is a versatile coating for diverse materials.
• Interfacing PDA with DNA is vital for biosensing, drug delivery, and fabrication.
• Negative surface charge of PDA at neutral pH causes electrostatic repulsion with DNA.

Purpose of the Study:

• To investigate transition metals' efficiency in promoting DNA adsorption onto PDA.
• To compare the effectiveness of Mn2+, Co2+, Zn2+, and Ni2+ with Ca2+.
• To understand the role of PDA aging and metal ions in DNA binding.

Main Methods:

• Comparing DNA adsorption onto PDA using various divalent metal ions (Mn2+, Co2+, Zn2+, Ni2+, Ca2+).
• Analyzing DNA-PDA interactions and the influence of PDA aging.
• Evaluating DNA sensing selectivity based on adsorption affinity.

Main Results:

• Transition metals (Mn2+, Co2+, Zn2+, Ni2+) significantly enhanced DNA adsorption compared to Ca2+.
• DNA phosphate backbone dominated adsorption, with potential DNA base interaction for strong binding metals (Ni2+).
• Higher adsorption affinity correlated with increased sensing selectivity for complementary DNA.
• PDA aging reduced DNA adsorption, but Zn2+ and Ni2+ mitigated this effect.
• Storing PDA at 4°C slowed down the aging process.

Conclusions:

• Divalent transition metals effectively promote DNA adsorption onto PDA surfaces.
• Zn2+ and Ni2+ offer a strategy to overcome PDA aging limitations for DNA immobilization.
• Optimized DNA-PDA interactions using specific metal ions enhance biosensing capabilities.