Self-powered nanoparticles may deliver drugs to heal bones faster

U.S. scientists say cracks in bones can be healed with a new method of delivering drugs directly to the cracks on the backs of tiny self-powered nanoparticles. Chemists and bioengineers at Penn State University and Boston University report the energy to power the nanoparticles and send them rushing toward the crack is taken from a surprising source -- the crack itself. "When a crack occurs in a bone, it disrupts the minerals in the bone, which leach out as charged particles -- as ions -- that create an electric field, which pulls the negatively charged nanoparticles toward the crack," Penn State chemistry Professor Ayusman Sen said. "Our experiments have shown that a biocompatible particle can quickly and naturally deliver an osteoporosis drug directly to a newly cracked bone." Formation of this kind of electric field is a well-known phenomenon but has never been used as both a power source and a homing beacon to actively deliver bone-healing medications to the sites most at risk for fracture or active deterioration in condition such as osteoporosis, Sen said. In the new research, negatively charged nanoparticles carrying drugs have been found to move toward and pile up on a newly formed crack, the researchers said. "Our experiments show that [a] bio-safe nanomotor can, in fact, successfully carry the osteoporosis drug to a fresh crack in a human bone," Sen said. In current treatments, medications ride passively on the circulating bloodstream where they may or may not arrive at microcracks in a high-enough dosage to initiate healing, the researchers said. "What makes our nanomotors different is that they can actively and naturally deliver medications to a targeted area," Sen said.