A team of engineers have created a sperm-like biological "bot" that can self-propel through viscous environments. The technology is detailed in a recent edition of Nature Communications

The "tiny bio-hybrid machines" are the first synthetic structures capable of moving through the viscous fluids of biological environments on their own, according to the University of Illinois, which was involved in the creation of the biobot.

"Micro-organisms have a whole world that we only glimpse through the microscope," said Taher Saif, a professor of mechanical science and engineering at Illinois. "This is the first time that an engineered system has reached this underworld."

The creation is modeled after a flagella, single-celled organisms with a long tail. Sperm is an example of a flagella.

The outer casing of the biobot is a flexible polymer, and inside, a culture of heart cells power the creation forward by beating, which generates movement in the tail.

"It's the minimal amount of engineering - just a head and a wire," Saif said. "Then the cells come in, interact with the structure, and make it functional."

Saif and his team also built two-tailed biobots, which are capable of swimming even faster than the single-tailed ones. While much more work needs to be done to perfect the system, a two-tailed biobot would be capable of navigation, which could allow the system to be travel to specific locations inside a body.

"The long-term vision is simple," Saif said. "Could we make elementary structures and seed them with stem cells that would differentiate into smart structures to deliver drugs, perform minimally invasive surgery or target cancer?"

Roger Kamm, a professor of biological and mechanical engineering at the Massachusetts Institute of Technology, said the "most intriguing aspect of this work is that it demonstrates the capability to use computational modeling in conjunction with biological design to optimize performance, or design entirely different types of swimming bio-bots."

"This opens the field up to a tremendous diversity of possibilities. Truly an exciting advance," he said.