After the COP platelets were coated with P25 or with the precursor tetraisopropoxide, the platelets were heat treated with a laser (Epilog Zing 24, 30 W CO2-laser). Three different relative laser intensities (8, 9 and 10%) were investigated. To treat the whole sample, the laser was scanned over the sample in parallel lines until the entirety of the sample was exposed to an equal dosage. For the WLEs, only the coated upper hemisphere was treated by scanning in adjoining concentric rings with a laser intensity of 9%. The hemisphere of the WLE has both a height and radius of 5 mm. A total of 12 concentric rings were lasered onto the WLEs, each with a laser thickness of 0.4 mm (laser setting: grid: Floyd, speed: 90%, power: individual 7, 8, 9 or 10%). The schematic representation can be found in the supporting information in Figs. and.