Scientists engineer cyborg cells in the fight against pathogens, poisons and pollutants
We have all watched sci-fi movies with robots and cyborgs that are stronger than humans. Some of us have played computer games with special goggles that replace our environment with virtual reality.
Now imagine if we can make cyborgs out of single cells. It sounds like something from the distant future but actually it is already a reality which started more than five years ago in a research lab at the University of Hull.
Professor Vesselin Paunov, who leads a team of biomaterials experts in the Department of Chemistry, succeeded in turning ordinary cells like baker’s yeast into ‘cyborg cells’. The researchers managed to ‘wrap’ the cells with special polymers and very tiny particles while keeping them alive.
“The cells interact with their environment through their cell membrane,” explains Professor Paunov.
“If we furnish the cells with an artificial interface by coating them with certain particles or polymers, they can perform completely new roles. For the cells, this artificial interface looks like putting on virtual reality goggles.”
“We can use these cells to build useful devices, such as detecting pollution and even fighting microbes.”
Detecting toxins and pollutants with magnetic yeast
The Hull team have used magnetic nanoparticles to make magnetic yeast, whose cells can be moved around and extracted from solution with a strong magnet.
They magnetised a special strain of yeast cells, then trapped them in a device called a ‘lab-on-a-chip’ – a device which shrinks the pipettes, test tubes and analysis instruments of a modern chemistry lab onto a microchip-sized wafer of plastic.
The tiny lab-on-a-chip has many ingrained grooved channels, and the magnetic cells are held in these channels with a magnet.
Using the lab-on-a-chip device, different liquid samples can be quickly screened for toxicity by flowing them over the cells in the channels. The yeast cells look fluorescent under a microscope when they are exposed to genotoxins as they activate their DNA-repair gene which triggers another gene that produces green fluorescent protein.
“We also collaborated with colleagues at the University of Sheffield to detect environmental pollution using bacterial cyborg cells,” explains Professor Paunov.
“Mixing them with polluted soil gets them exposed to the pollutants trapped in the pores of the soil particles. When collected back with a magnet and examined, the way the cells respond tells us how concentrated the pollutant is.”
Fighting microbes with nanogold – and no antibiotics
The team of scientists at Hull led by Professor Paunov have developed a new family of selective antimicrobial agents which could hold the key to fighting microbes without the use of traditional antibiotics.
The team have discovered a way of custom-designing microparticles to recognise the shape of specific microbes and ‘de-activate’ them.
“This idea has many applications, as it allows killing microbes selectively without antibiotics,” says Professor Paunov.
“Since many superbugs have developed resistance to the available antibiotics, this technology may help us to build the next lines of defence from resistant microbial infections.”
Professor Paunov’s team have created innovative antimicrobial agents by using the microbes as templates. First, they coated the target microbes with very tiny gold particles and thin shells of silica, the same material as ordinary sand.
They broke those shells in large fragments which ‘remember’ the shape of the templated microbial cells, so when they encounter cells that match their shape they bind to them selectively. The researchers named these particles ‘colloid antibodies’ as they recognise whole cells.
When the researchers incubated colloid antibodies with a mixture of different microbes, they bind only to the original cells and bring gold particles directly on their surface.
Since gold nanoparticles absorb light strongly, shining a laser on the mixture makes them heat up and kill the cells in contact. It is a bit like designing microscopic baking moulds but for microbes, not cupcakes!