We have been using antimicrobial agents in coatings quite successfully for years. Certainly the use of silver has been very successful.  So it caught me by surprise when late last year hospital giant Kaiser Permanente, which operates hundreds of health care facilities in the U.S., banned antimicrobial coatings for new construction and renovations. In retrospect, I should not have been surprised as they had been advocating to discontinue using antimicrobial products since 2006. They claim that the CDC has found no evidence to suggest these products offer protection from the spread of bacteria and that proper cleaning and hand washing is the best approach. Prior to this they stopped using furniture containing flame retardants.

I understand their concern regarding toxic chemicals but I also believe that the coatings which incorporate antimicrobials are safe for use and have had positive effects. There has been ample past evidence supporting the use of antimicrobials in coatings and also the safe use of flame retardants. The downside is that bacteria do become resistant over time to many agents.

On a positive note, researchers at the Institute of Bioengineering and Nanotechnology (IBN) of A*Star in Singapore have developed a new material that can kill E. coli bacteria within 30 seconds.

“The global threat of drug-resistant bacteria has given rise to the urgent need for new materials that can kill and prevent the growth of harmful bacteria. Our new antimicrobial material could be used in consumer and personal care products to support good personal hygiene practices and prevent the spread of infectious diseases,” said IBN Executive Director, Professor Jackie Y. Ying.
Triclosan, a common ingredient found in many products such as toothpastes, soaps and detergents to reduce or prevent bacterial infections, has been linked to making bacteria resistant to antibiotics and adverse health effects. Driven by the need to find a more suitable alternative, IBN Group Leader Dr. Yugen Zhang and his team synthesized a chemical compound made up of molecules linked together in a chain. Called imidazolium oligomers, this material can kill 99.7% of the E. coli bacteria within 30 seconds aided by its chain-like structure, which helps to penetrate the cell membrane and destroy the bacteria. In contrast, antibiotics only kill the bacteria without destroying the cell membrane. Leaving the cell structure intact allows new antibiotic-resistant bacteria to grow.

“Our unique material can kill bacteria rapidly and inhibit the development of antibiotic resistant bacteria. Computational chemistry studies supported our experimental findings that the chain-like compound works by attacking the cell membrane. This material is also safe for use because it carries a positive charge that targets the more negatively charged bacteria, without destroying red blood cells,” said Dr. Zhang.”The imidazolium oligomers come in the form of a white powder that is soluble in water. The researchers also found that once this was dissolved in alcohol, it formed gels spontaneously. This material could be incorporated in alcoholic sprays that are used for sterilization in hospitals or homes. Besides E. coli, IBN’s material was also tested against other common strains of antibiotic-resistant bacteria and fungi, such as Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans. These pathogens can cause conditions ranging from skin infections to pneumonia and toxic shock syndrome. Our material was able to kill 99.9% of these microbes within two minutes. IBN’s ultrafast, bacteria-killing material could therefore be a potent new weapon against drug-resistant microbes.”

Another new development has been introduced by researchers from the Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Ben-Gurion University of the Negev (BGU).

They have introduced an innovative anti-biofilm coating, which has significant anti-adhesive potential for a variety of medical and industrial applications.

According to the research published in Advanced Materials Interfaces, anti-adhesive patches that are developed from naturally occurring biomaterials can prevent destructive bacterial biofilm from forming on metal surfaces when they are immersed in water and other damp environments.

“Our solution addresses a pervasive need to design environmentally friendly materials to impede dangerous surface bacteria growth,” said the researchers. “This holds tremendous potential for averting biofilm formed by surface-anchored bacteria and could have a tremendous impact.”

The anti-adhesive could be used on medical implants, devices and surgical equipment where bacteria can contribute to chronic diseases, resist antibiotic treatment and thereby compromise the body’s defense system. The prevention of aquatic biofouling on ships and bridges is one of the industrial applications.