Kinase Activity Assay

To measure the kinase activity of the DGK samples, the assay published by Lau et al. was used.²⁵ The spectrometer was blanked against the DGK dialysis buffer. A 10 μL portion of the sample was then added and mixed in and the absorbance at 340 nm was monitored over 30 min every 2 s. For the nanoparticle samples, 20 μL of resuspended nanoparticles was preincubated with 10 μL of dioleylglycerol (7 mM, in DMSO) for 20 min before the mixture was added to the cuvette. Accordingly, the volume of buffer was reduced to 362 μL.