A tube of human serum albumin and poly-arginine can be made just the right size to filter harmful E. coli from drinking water
E. coli bacteria are common and most are not harmful to humans. Some strains, however, can pose severe threats to human health. Every once in a while you hear of food recalls due to harmful strains of E. coli contaminating food or drinking supplies. This is especially a problem in developing nations, where food may be washed in contaminated water and cause food poisoning.
A group of Japanese researchers have developed a way to remove E. coli bacteria from water supplies using tubes made from human serum albumin and poly-arginine peptides. Scientific American describes the process:
The elegant method, devised by Teruyuki Komatsu and co-workers at Chuo University, Tokyo, begins by depositing microtubes made from alternating layers of human serum albumin (HSA) and poly-L-arginine onto a polycarbonate template. The template is then dissolved away to leave a hollow tube, which is just the right size to fit the E. coli bacterium. Key to removing E. coli from a solution is its strong binding affinity for HSA, which attracts the bacteria into the tube. So effective is this binding, that just 1.5μg of microtubes, added to a liter of contaminated water containing 100,000 bacteria were able to remove the bacteria with almost 100% efficiency. The final touch is the incorporation of a layer of magnetite (iron (II) oxide) nanoparticles into the microtubes to allow their easy removal from the solution using a magnetic field.
