"One of the major drawbacks of chemotherapy is that it damages far more of the body than just the malignant tumors it's used to fight. In order to target just the cancerous areas, and not hit everything on the way there, researchers from the University of Texas in El Paso created a tiny solar cell. They attached model drugs to each side of the cell, one of which was positively charged, the other negatively. Once the tiny solar devices are in the body, they're targeted with an infrared or laser light blast, causing it to release the drugs. This would mean the medication would only be released at a specific juncture, and could be used to deliver the medical payload extremely specifically."