MIT has created a chip-based optical tractor beam that can focus a penetrating beam of light over 5 millimeters away from the surface of the chip itself. That might not sound like much, but it's a game-changer compared to previous integrated "optical tweezers" that could only work within a few microns of the chip. Those older approaches essentially had to remove cells from their sterile glass containers (used commonly for biological experiments) and place them directly on the chip's surface, raising contamination risks.