Phototactic behavior directs some bacteria towards light and others into darkness: This enables them to utilize solar energy as efficiently as possible for their metabolism, or, otherwise, protects them from excessive light intensity. A team of researchers have now found a surprisingly simple way to direct synthetic microswimmers towards light or darkness. Their findings could eventually lead to minuscule robots that seek out and treat lesions in the human body.

Source: Microswimmers can be propelled and steered by light