COOH-PLGA(5k)-PEG(2k)-MAL is an amine-reactive amphiphilic block copolymer. The reaction between carboxyl and amine occurs via activation with HATU/EDC. The maleimide group can react with thiol to form a stable thioether bond. The polymer consists of a hydrophobic segment (poly(lactide-co-glycolide) (PLGA)) and a hydrophilic block (PEG) which can form micelles in water with the PEG facing the water and the PLGA being shielded from the water. The self-assembling behavior allows an efficient drugs encapsulation for drug delivery with improved stability and blood circulation while avoiding immune response (stealth). Reagent grade, for research purpose.