Researchers at Tokyo Metropolitan University have developed advanced nanostructured aluminum oxide surfaces that are highly effective at killing bacteria while supporting the growth of cultured cells. New nanostructured aluminum oxide surfaces have unprecedented antibacterial properties and could provide a safer cell culture environment for regenerative medicine without the use of antibiotics.

The team demonstrated that their nanostructured surface inhibited bacterial growth but allowed it to grow cells. Source: Tokyo Metropolitan University

By using an electrochemical process in concentrated sulfuric acid, the research team created an anodic porous aluminum oxide (APA) surface with special antimicrobial properties. These surfaces prevent bacterial growth without interfering with cell culture, providing a breakthrough solution for regenerative medicine. This technology can produce high-quality cell cultures free of bacterial contamination without relying on antibiotics.

Antimicrobial surfaces are critical for both public health and everyday applications. Traditional methods involve the use of antibiotics and harsh chemicals, but these methods harm the environment, pose health risks, and lead to an increase in antibiotic-resistant bacteria. Now more than ever, alternative ways to combat bacterial pathogens are needed, and nanostructured surfaces like APA may offer a safer, more sustainable solution.

This is where nanostructured surfaces come in. In the early 2010s, research showed that naturally occurring nanostructures on cicada and dragonfly wings could protect against bacterial contamination. These structures damage the membranes of bacterial cells, preventing them from spreading. So scientists have been looking for ways to cheaply create artificial surfaces that can achieve the same effect.

Breakthrough advances in antimicrobial and cell-friendly surfaces

A research team led by Professor Takashi Yanagishita of Tokyo Metropolitan University has been exploring the application of anode porous alumina (APA). When a polished aluminum surface is immersed in an electrochemical cell under certain conditions, the surface is coated with an ordered layer of porous aluminum oxide (alumina) pillars. These needle-like pillars are just the right size to kill bacteria, making the aluminum surface highly antimicrobial.

Now, the research team has perfected their formula and found that the antibacterial properties of APA surfaces prepared in concentrated sulfuric acid are significantly better than existing surfaces. Most importantly, they found that the surface did not harm biological cells cultured on it. In normal cell culture, antibiotics may be added to the culture medium to prevent bacterial contamination. The main disadvantage of this is that it is useless against antibiotic-resistant bacteria; in fact, overuse of antibiotics may again lead to the emergence of more resistant strains. The APA surface is different. Cultures can be performed safely without the use of antibiotic additives.

Revolutionary applications in medicine

The team's findings are good news for regenerative medicine, which grows cells in the laboratory and then injects them into patients to treat tissue and organ damage. Any bacterial invasion of cells can have dire consequences for the patient: this often requires a specialized and expensive sterile environment. The team believes their new substrate could enable antibiotic-free cell culture in a wider range of settings, potentially revolutionizing the scale at which patients are treated and the way we conduct scientific experiments.

Compiled from /scitechdaily