Algae aren鈥檛 just scum on the top of a lake: some of the microbes can swim surprisingly fast 鈥� outpacing even the micromachines designed to one day deliver drugs inside the human body. Now comes evidence that the alga could be harnessed relatively easily for such speedy drug delivery.
Metin Sitti at the Max Planck Institute for Intelligent Systems in Germany and his colleagues figured out a way to yoke an alga like an ox and then steer it through the body using magnetic fields as the reins.
They started by attaching spherical magnets just one micrometre across to a single freshwater alga. Then they could control the alga鈥檚 direction as it swam along by applying a magnetic field, which pulled the tiny magnets in whatever direction they want the alga to go. 鈥淚t鈥檚 a cyborg-like system,鈥� says Sitti.
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Targeted response
The idea is to load the algae up with medication and then steer them through the body to diseased tissue for a targeted response, rather than simply drugging the whole surrounding area or the entire body, which can have unpleasant side effects. The algae can swim over 100 micrometres per second, much faster than many other microswimmers that have been proposed for drug delivery.
Sitti and his team found that the algae can swim in the fluid within Fallopian tubes, and also in both plasma and blood. What鈥檚 more, they are biocompatible with human cells.
The researchers are now working on making sure that immune cells won鈥檛 attack the algae before they can reach their destinations. 鈥淲e know that they hate bacteria and they attack bacteria, but we now think that they are nicer to the algae and do not attack for a day or so, which is more than enough time,鈥� says Sitti.
Advanced Materials
