Novel amphiphilic PELGA modified temperature-responsive copolymer, [(poly(methoxyethylene glycol)-co-poly(lactic acid)-co-poly(glycolic acid))acrylate-co-poly(N-isopropylacrylamide)-co-poly(N-hydroxymethylacr ylamide)] (PELGAA-co-PNIPAAm-co-PNHMAAm) was synthesized by incorporating PELGA as the amphiphilic moiety into poly(N-isopropylamide) with various LA/GA ratios. Polymers obtained were characterized by FT-IR. GPC H-1-NMR and DSC. The lower critical Solution temperature (LCST) of the copolymeric nanoparticles was 40 +/-0.6 degrees C, the critical aggregation concentration (CAC) was 18 mg L-1, and reversible change in nanoparticle size related to temperature was fluctuated between 210 +/- 10 and 109 +/- 26 run, while change in zeta potential of the nanoparticles was between -36 +/- 6 and -26 +/- 4 mV. The transmission electron microscopy (TEM) images of nanoparticles were also presented. (c) 2005 Elsevier Ltd. All rights reserved.