Oxygen clusters key to unlocking graphene’s antimicrobial potential, scientists say

The amount of surface oxygen in graphene materials is a key factor in their effectiveness in killing bacteria – a finding that could help design safer and more effective products to combat antimicrobial resistance.

High surface oxygen (SOC) graphene oxide is very flexible and can wrap around bacteria (a parallel mode of contact), but when it has a lower SOC the material has more stiffness. high and tends to come into contact with the bacteria on the edges (in perpendicular mode).

Neither mode necessarily kills bacteria, but bactericidal activity depends on how the material interacts with surrounding biomolecules. This discovery will help scientists understand the different possible physical mechanisms leading to their antibacterial activity.

Publish their findings in ACS-nanoan international group of scientists from the UK, Cyprus, Austria, Finland, the Netherlands and China reveal that it is the different modes of interaction of graphene oxide that lead to distinct antibacterial activity , with a “switch” occurring when surface oxygen levels reach a certain threshold. .

A slight change in SOC can cause the modes of interaction between parallel and perpendicular contact to shift. “The impact of SOC on the mode of interaction has long been underestimated,” commented Dr Zhiling Guo, from the University of Birmingham.

Dr Peng Zhang from the University of Birmingham commented: “Our research highlights that surface oxygen levels can help assess the antibacterial effects of graphene materials, helping to design safer materials by clarifying the role of the SOC.”

As antimicrobials, graphene-based materials may have advantages over traditional antibiotics due to their physical mechanisms of action that reduce the chances of developing microbial resistance.

So far, the fundamental question of whether the antibacterial mechanism of graphene materials arises from parallel interaction or perpendicular interaction, or a combination thereof, remains poorly understood, hampering progress. in developing antibacterial graphene materials and understanding their environmental safety.

Professor Iseult Lynch, from the University of Birmingham, said: “The discovery is a potential ‘game changer’ and we should use this surface oxygen ‘switch’ as ​​the defining property to define and classify graphene materials. in the context of human health and the environment. security.”

The UK-led international research team created a series of graphene materials with different SOCs and compared their antibacterial performance, assessing total cell growth, biofilm formation and oxidative stress, as well as interactions with bacteria, in particular through molecular simulations.

Different modes of interaction lead to distinct antibacterial activity and the mode of interaction is strongly related to the stiffness of graphene materials which depends on the amount of surface oxygen.

Antibacterial activity of graphene materials was reported as early as 2010. The material has been used to create antibacterial fabrics for maternity wear that can prevent microbial growth on the surface of the fabric. Graphene-coated nonwoven fabrics have been used to produce antibacterial face masks, while graphene-based membranes have been widely studied for water treatment due to their ultra-fast water transport and anti-fouling activity. .