Chinese tech giant Baidu is in talks with investors to raise up to US$2 billion over three years for a biotech start-up, which will use artificial intelligence (AI) technology to discover new drugs and diagnose diseases, a person with direct knowledge of the matter said.A second person confirmed the start-up plan.Baidu is unlikely to be the controlling investor, the first person said. Both sources spoke on condition of anonymity, adding they did not have more details on the investment as talks…