Living hybrid microbots can decontaminate water.
Biohybrid microrobots are composed of a living organism integrated with artificial materials. Biohybrid microbots take advantage of the natural actuation and sensing mechanisms of motile microorganisms, such as bacteria and algae which could one day be used to deliver disease-fighting drugs or attack tumors in the body. In contrast to their synthetic counterparts, microorganism-powered microrobots can sense and respond to changes in their local environment, providing a higher level of autonomy. However, many technical obstacles still have to be circumvented before microbots become standard operating procedure in medicine Now, a study from researchers at University California San Diego develops a biohybrid microrobot, employing self-propelled marine bacteria as their engine, to decontaminate water. The team states this is the first demonstration of a biohybrid cyborg used for the removal and degradation of pollutants from solution. The opensource study is published in the journal Advanced Functional Materials.
Previous studies show most microorganisms can achieve high propulsion speeds, with the ability to traverse tight junctions with cargo, making them highly plausible for many applications inside and outside of the body. One application for biohybrid micromotors is water decontamination, for instance, the active degradation of pollutants in solution. However, a major challenge in this field is the diffusion of toxic pollutants and the short time span biohybrid microbots have to clear them. The current study develops biohybrid microrobots that integrate fast-moving self-propelled bacteria with functionalized synthetic nanostructures to transport materials.
The current study engineers a self-propelled biohybrid microrobot, dubbed rotibot, employing rotifer bacterium as their engine. Rotifers are marine microorganisms, which measure between 100 and 300 micrometers, that possess sensing ability, energetic autonomy, and provide large-scale fluid mixing capability. They are also are very resilient and can survive in extreme environments. Functionalized microbeads are attached electrostatically within the rotifer mouth and aggregated inside their inner lip. Results show the high fluid flow toward the mouth, generated by the strokes of rotifer cilia bands, forces efficient transport of the contaminated sample over the active surfaces of the functionalized microbeads.
Data findings show the rotifer serves as a transport vessel for the cargo and acts as a powerful biological pump, causing the contaminated liquid towards its mouth, and the active material. The lab states they have successfully demonstrated the accelerated decontamination of E. coli bacteria, methyl paraoxon nerve agent, and cadmium and lead heavy metal ions from aqueous solutions turning the cyborg into a kind of ‘micro-Roomba’. They go on to add that their hybrid cyborg holds considerable promise as self-propelling dynamic pumps for diverse large-scale environmental remediation applications.
The team surmises they have engineered a hybrid self-propelled microbot proffering autonomous movement, actuation, and sensory perception to decontaminate water quickly. For the future, then researchers state they plan to make their platform fully degradable by replacing the plastic microbeads, with biodegradable functional microparticles; they also plan to introduce swarm-like behavior.