PLGA-PEG-MAL (20kDA-5.0kDA, LA:GA ratio 50:50) is a kind of poly (lactide-co-glycolide) -block-poly (ethylene glycol) (PLGA-PEG-Mal) nanoparticles. PLGA-PEG-MAL (20kDA-5.0kDA, LA:GA ratio 50:50) has a molecular weight of 20kDA to 5.0kDA and contains a 50:50 ratio of lactic acid (LA) to glycolic acid (GA) molecules. The molecular ratio of LA to GA determines the rate of matrix degradation and protein re-release[1][2].