Promoting DNA Adsorption by Acids and Polyvalent Cations: Beyond Charge Screening

Area of Science:

• Nanomaterials Science
• Biotechnology
• Surface Chemistry

Background:

• DNA oligonucleotide adsorption onto nanoparticles is key for DNA-based biosensors, drug delivery, and smart materials.
• DNA's polyanionic nature causes repulsion from negatively charged nanoparticles, hindering adsorption.
• Conventional salt (NaCl) addition screens repulsion but lacks attractive forces and can cause aggregation.

Purpose of the Study:

• To summarize methods developed in the lab to enhance DNA adsorption onto various nanomaterials.
• To investigate the effects of pH reduction and polyvalent metal ion addition on DNA adsorption.
• To discuss the applicability of these methods across diverse nanomaterial types.

Main Methods:

• Investigated DNA adsorption on noble metals, 2D materials (graphene oxide, MoS2, WS2, MXene), polydopamine, and metal oxides.
• Manipulated solution pH to alter surface charges and DNA protonation.
• Introduced polyvalent metal ions, particularly transition-metal ions, to mediate adsorption.

Main Results:

• Lowering pH can reduce charge repulsion and induce attraction by protonating DNA and nanoparticle surfaces.
• Polyvalent metal ions facilitate adsorption by creating bridging interactions.
• Successful DNA adsorption was demonstrated on a range of materials including gold, graphene oxide, and MXene.

Conclusions:

• pH modification and polyvalent metal ion addition are effective strategies for promoting DNA adsorption.
• These methods overcome limitations of traditional salt addition, enabling broader applications in nanotechnology.
• Future research should focus on optimizing these techniques for improved DNA adsorption and functionality.