Surface-functionalization effects on uptake of fluorescent polystyrene nanoparticles by model biofilms

Area of Science:

• Environmental Science
• Materials Science
• Microbiology

Background:

• Biofilms effectively remove nanomaterials from water.
• Mechanisms of nanoparticle uptake by biofilms are not well understood.

Purpose of the Study:

• Investigate the influence of nanoparticle surface functionalization and charge on biofilm uptake.
• Determine if nanoparticle core composition or surface properties are key drivers of interaction.

Main Methods:

• Laboratory-cultured biofilms were incubated with fluorescent polystyrene nanoparticles.
• Nanoparticles with varying surface charges (negatively charged sulfated and carboxylated, positively charged amine) were used.
• Particle association with biofilms was quantified under different ionic conditions.

Main Results:

• Nanoparticle uptake was primarily dependent on surface charge, not core composition.
• Negatively charged sulfated nanoparticles exhibited the strongest association with biofilms.
• Positively charged nanoparticles showed ionic strength-dependent association, strongest in high ionic conditions.
• Carboxylated nanoparticles showed the lowest association, insensitive to ionic strength.

Conclusions:

• Nanoparticle surface charge is a critical factor governing their interaction with biofilms.
• Biofilms show a strong affinity for negatively charged nanoparticles, particularly sulfated ones.
• Biofilms may play a significant role in the environmental sequestration of nanoparticles.