The spongelike structure of metal-organic frameworks (MOFs) allows these polymers to possibly carry and deliver a range of therapeutic compounds. Now, researchers reporting in ACS Applied Bio Materials have treated a chromium-containing MOF with a dose of acetic acid, more concentrated than in vinegar, to expand its pore size and surface area. The puffed-up MOF held more ibuprofen or chemotherapy drug than the original version and showed improved performance as a potential drug-delivery vehicle.