Have you ever marvelled at the movement of water droplets on a lotus leaf? What about the ability of lizards to stay on a wall while being upside-down? Have you ever wondered how all these happen?
Let’s take a look at the leaf. The surface of the lotus leaf is highly hydrophobic, which means that it repels water (hydro: water, phobic: phobia/fear). Therefore, water droplets will remain in shape as they travel along the surface of the leaf.
For lizards, they are equipped with adhesive bristles on their feet and this feature allows them to defy gravity as they crawled up a wall.
This “lotus-effect” and “gecko-effect” can be exploited by scientists to develop materials that are beneficial to the society, including water-repellent coating and strong gripping adhesives. The manipulation of these features at the atomic level is known as nanotechnology.
Nanotechnology to combat bacteria
As interesting as they sound, the “lotus-effect” and “gecko-effect” are just a scratch on the surface of what nanotechnology offers.
One of the recent advancements in this field is the use of the surface of cicada wings to physically kill bacteria. Like a bristle brush, the surface of cicada wings consists of “spikes” that are able to pierce through bacteria. Using this technology, bacteria that accumulate on biofilms can be killed and this will prevent further accumulation of other biofouling materials on surfaces.
With the rise of antibiotic resistant strains of bacteria, it is evident that there is a need to discover new innovative ways to kill these deadly bacteria. While many researchers are attempting to find chemicals to make antibiotics, there is an increase in the use of physical tools to kill bacteria through the use of nanotechnology.
The beauty of using physical methods to kill bacteria is that bacteria are less likely to develop resistance to such methods. In 2016, a star-shaped polymer was nanoengineered and it exhibited the ability to rip apart bacteria. This technology opened up avenues to combating multi-drug resistant bacteria.
Pogodin S, Hasan J, Baulin VA, Webb HK, Truong VK, Phong Nguyen TH, Boshkovikj V, Fluke CJ, Watson GS, Watson JA, Crawford RJ, Ivanova EP. (2013) Biophysical model of bacterial cell interactions with nanopatterned cicada wing surfaces. Biophys J. 104(4):835-840.
Lam SJ, O’Brien-Simpson NM, Pantarat N, Sulistio A, Wong EH, Chen YY, Lenzo JC, Holden JA, Blencowe A, Reynolds EC, Qiao GG. (2016) Combating multidrug-resistant Gram-negative bacteria with structurally nanoengineered antimicrobial peptide polymers. Nat Microbiol 1(11):16162.