Researchers at IIT Mandi have developed a bio-inspired coating for 3D-printed bone implants made of polylactic acid (PLA), a biodegradable plastic whose surface does not bond easily with bone. The coating consists of tiny hydroxyapatite structures shaped like sea urchins that physically damage bacteria. It improves integration with bone and reduces infection without antibiotics or antibacterial chemicals. The implant is treated with an alkaline solution and then hydrothermally at 90°C, producing needle-like hydroxyapatite clusters.