Noncovalent Interactions between Dopamine and Regular and Defective Graphene.

Area of Science:

• Materials Science
• Computational Chemistry
• Biophysics

Background:

• Noncovalent interactions are crucial for biological molecule adsorption on graphene.
• Graphene's potential in biosensing and drug delivery relies on understanding these interactions.
• Dopamine adsorption on graphene surfaces is a key area of study.

Purpose of the Study:

• To theoretically investigate dopamine adsorption on pristine graphene and graphene with monovacancies (GV).
• To identify stable adsorption configurations and the nature of interactions involved.
• To explore the impact of vacancies on dopamine adsorption and electronic properties.

Main Methods:

• Density Functional Theory (DFT) calculations were employed.
• Various adsorption modes, including parallel and quasi-parallel orientations, were considered.
• Electronic charge redistribution was analyzed to understand interaction mechanisms.

Main Results:

• The most stable adsorption configurations involve dopamine oriented parallel or quasi-parallel to the graphene surface.
• Dopamine adsorption on graphene is characterized by attractive dispersive forces counteracting Pauli repulsion.
• A hydrogen bond forms between dopamine and graphene at a monovacancy site in the A-B stacking mode.
• Adsorption leads to an electronic charge drift from the graphene/GV surface to the dopamine molecule.

Conclusions:

• Dopamine's interaction with graphene is primarily governed by dispersive forces and Pauli repulsion.
• Graphene monovacancies can introduce specific binding sites, like hydrogen bonds, enhancing adsorption.
• The observed electronic charge redistribution suggests potential for modulating graphene's electronic properties via dopamine adsorption.