Tokyo Metropolitan University researchers have unveiled new nanostructured alumina surfaces described as “strongly antibacterial but can be used to culture cells.” They report that “anodic porous alumina (APA) surfaces prepared using electrochemistry in concentrated sulfuric acid have unprecedented resistance to bacterial growth.” Yet, the team emphasizes that these surfaces “do not hamper cell cultures.”
According to the researchers, “the technology developed by the Tokyo Metropolitan University researchers promises to have a significant impact on regenerative medicine.” These surfaces “may enable the production of high-quality cell cultures without bacterial contamination and without the use of antibiotics.”
Scientists have long sought ways to control bacterial contamination without relying solely on powerful antibiotics. “Surfaces that resist bacterial contamination play a vital role in public health and daily life,” they note, underscoring that “achieving bacterial resistance with powerful antibiotics and chemicals entails negative environmental impact and health hazards.”
This pursuit echoes discoveries from the early 2010s, when “it was shown that the naturally formed nanostructure on the wings of cicadas and dragonflies can resist bacterial contamination.” Those natural surfaces work by “damaging the cell membrane of bacterial cells and prevent them from spreading.” Researchers have been searching for ways to replicate that effect, and a team led by Professor Takashi Yanagishita from Tokyo Metropolitan University turned to APA for inspiration.
When a polished aluminum surface is treated under the right electrochemical conditions, “the surface is coated with a well-ordered array of porous pillars of alumina (aluminum oxide).” These “needle-like pillars are just the right size to be deadly to bacteria, making the surfaces strongly antibacterial.” The team found that “APA surfaces prepared in concentrated sulfuric acid have antibacterial properties that significantly outperform existing surfaces,” while still being “not hazardous to biological cells cultured on them.”
Under normal laboratory routines, scientists often add antibiotics to cell cultures to keep bacteria at bay. However, “the use of antibiotics in cell cultures has the major drawback of being ineffective against antibiotic-resistant bacteria,” and “the overuse of antibiotics in cell cultures might lead to the emergence of more resistant strains.” The Tokyo Metropolitan University team indicates that “cultures may be safely carried out on anodic porous alumina surfaces without antibiotic additives.”
They say this is “good news for regenerative medicine” because “any bacterial contamination in the cultured cells may have dire consequences for sick patients.” In particular, “cells are cultured in the lab before being introduced to a patient to treat tissue and organ damage,” so safe materials are crucial. Though “using anodic porous alumina surfaces usually entails specialized and costly sterile environments,” the researchers suggest that “their new substrates might enable antibiotic-free cell culture in a wider range of settings” and “could revolutionize the scale at which patients may be treated and how scientific experiments are conducted.”
The article was written with the assistance of a news analysis system.