Bubble-powered robots: How collapsing cavities could replace needles

A joint US-Chinese research team has developed a novel propulsion method for tiny robots using cavitation—the rapid collapse of bubbles in liquid—to generate mechanical energy. By heating light-absorbing materials with a laser, these microbots, called “jumpers,” create expanding bubbles that collapse violently, releasing shockwaves powerful enough to propel millimeter-sized devices up to 1.5 meters into the air or enable swimming speeds of about 12 meters per second. This laser-controlled bubble collapse allows precise control over movement, including jumping, sliding, or swimming, enabling navigation through complex environments such as microfluidic channels. This breakthrough has significant potential applications in medicine, particularly as a minimally invasive alternative to needle-based drug delivery. The cavitation-powered microbots could be launched through the skin to deliver drugs directly to targeted sites like tumors, overcoming limitations of current microrobots that rely on magnetic fields or chemical fuels. Additionally, these devices could explore confined or harsh environments, including inside pipes or biological systems,