I'm Cindy Gunawan and I am a nanobiologist.
So what is a nanobiologist?
It is a study in which I try to understand how nanoparticles interact with bacteria and actually to actually use that knowledge of how the bacteria interact with nanoparticles to design the nanoparticles such that it can actually exhibit a specific biological functions.
So this is the nanoparticles that I've been working with, it is the silver nanoparticles. It is very tiny. It's about 2 nanometres only and as a comparison to compare to a marble which is 15 milinanometres and this one is the human hair and it's 100000 nanometres. So because of this tiny size, the silver nanoparticles has an enhanced or remarkable anti-microbial activity. It can kill a wide range of microorganisms from bacteria, algae, fungi and also even viruses.
Because of these remarkable properties of the anti-microbial silver nanoparticles it has been used a lot in medical devices such as here in wound dressings and also in catheters and companies have also been including these silver particles in increasing rates of consumer products such as in personal care products here in toothbrushes, soaps, toothpaste and kitchen appliances and even in baby products.
So because of these widespread and indiscriminate applications of the anti-microbial nanoparticles, there has been these escalating concerns that it will actually lead to bacterial resistance. The term bacterial resistance actually means that the antimicrobial agent in this case the nanoparticles are no longer effective against bacteria. So indeed our research has shown that bacteria including pathogens are actually capable to develop resistance to the antimicrobial nanoparticle in this case the silver. So we as scientists like to actually try to contribute a solution to this problem to actually create smart nanoparticles such that we can actually try to fight these superbugs.
So we know that these bacteria actually develop resistance to the nanoparticles because of the prolonged, continuous exposure to the nanoparticles. So what we're trying to do is that we are trying to actually, try to interrupt those continuous product exposure by creating nanoparticles with a tunable activity such that to play tricks on the bacteria. So this is how we did it just going like a bit into a science here. So this is how we play tricks on a bacteria with the nanoparticles. We have this a metal oxide nanoparticles called titanium dioxide. And on top of the titanium dioxide we put our silver nanoparticles. When we actually test these nanoparticles on a bacteria it actually kills the bacteria so we can see that here that the antibacterial activity of these nanoparticles is being switched on. So how to actually tune this antimicrobial activity.
So you might be wondering why we've actually been using this titanium dioxide. Titanium dioxide for a photo catalyst- It means that its activity is triggered by light, in this case the UV light. So if we shined a UV light here on the titanium dioxide you will have transfer of electrons from the low energy level to the high energy level and in turn, these electrons will flow to the metal to the silver deposits here. And in turn, the silver oxide is transformed to the metallic silver. And when we test these nanoparticles we could see that the intellectual activity is actually being switched off because the silver oxide here has been reduced or transformed to a metallic silver so we've seen the switching on the switching off of the antibacterial activity.
Lastly we're left to think as to whether we can actually do this in a cycle so because now we have the metallic silver here. We know that it will be responsive to fits of light. So this time we actually use different kind of light, visible light with lower energy. And when we shine a visible light go will be a reverse electron flow from the metallic silver back to the titanium dioxide and in turn, the metallic silver here is transformed back to the silver oxide and as you expected the anti-microbial activity will be switched on again. So this switching on off on off of the antibacterial activity of the nanoparticles we've found that it can actually delay the response of bacterial resistance to the nanoparticles.
So that's it for me (applause) and yeah this is just to show that you can actually use science to try to provide solutions to real global challenges in this case in the fight of energy microbial resistance.
6 September 2018
Cindy Gunawan is a nano-biologist who is fighting on the front lines against bacterial resistance! She's working on understanding the interactions between nanoparticles and cells to find our best weapon in the battle between mankind and microbes.
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