Alcohol — nearly always ethanol — is contained in most anti-bacterial hand sanitizers and swabs. But are they really as good as they could be?
Many household surface cleaning products use another kind of alcohol called isopropanol.
All alcohols dry out skin and may lead to cracks, opening a germ pathway. A young Montreal high school student, curious which kind of alcohol is most effective at killing bacteria and easiest on skin, took her question into a university science lab to test for an answer.
The first step for Nivatha Balendra, a 16-year-old attending Montreal’s Royal West Academy, was to determine whether ethanol or isopropanol was better at killing bacteria, which she tested by growing petri plates of bacteria and treating them with both alcohol types. The second step was to acquire enough cultured skin cells to see how the different alcohols affected them.
Verdict? Isopropanol was more effective in lower concentrations at killing bacteria than high concentrations of ethanol. It also killed fewer skin cells than ethanol.
“The result really defies what we all have been thinking, that ethanol is the best anti-bacterial agent,” says Nivatha. “Hand-sanitizing products are used constantly by patients and nurses at hospitals — and at home by children, people with weak immune systems, and a large chunk of our population. Just by changing the alcohol to Isopropanol, the risks faced by these people would be lowered.”
Isopropanol is a lot cheaper, she adds.
Her project was supervised in part by Carlos Melendez-Pena at the Research Institute of McGill University Health Center, and in part by Dr. Carter Li of the Plastic Surgery Research Centre, Montreal General Hospital.
Impressed by her determination, Mr. Melendez-Pena says Nivatha “was willing to put in the work needed to obtain a good project and good results.” Add Dr. Li: “Nivatha is a very hardworking and detail-oriented student. I have every confidence that Nivatha will excel in her studies and career and emerge as one of the leaders in the medical research field.”
Says Nivatha: “I want to pursue a career in medicine, to become a neurosurgeon, though after participating in this year’s competition, I learned how passionate I am about research.”