Chip-based Microcapsule Production Protocol

Chip-based hollow microcapsule production was performed as described previously^{54 (link),73 (link)}. In short, a polymethyl methacrylate (PMMA) microfluidic chip was used in a flow-focusing setup to produce droplets consisting of 5% Dex-TA and 250 U/ml HRP within an oil phase of n-hexadecane with the addition of 1% (v/v) Oil-red-O and 1% span 80 as a surfactant. The resulting emulsion was broken by three consecutive washes using n-hexadecane without surfactant and a subsequent wash with phosphate-buffered saline (PBS). Absorption of n-hexadecane with and without Oil-red-O and hollow microcapsules produced using chip-based microfluidics or IAMF was measured using spectrophotometry (Multiskan Go Microplate; Thermo Scientific) at 512 nm.