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To achieve controlled release of different growth factors at different periods (i.e. vascular endothelial growth factor (VEGF) followed by platelet-derived growth factor (PDGF)), and to investigate the effect of such release pattern on angiogenesis, we loaded model protein compounds BSA and lysozyme into microspheres based on PTMC with different molecular weights. Microspheres with size 1–50 μm and loading efficiencies higher than 75% were prepared. Microspheres loaded with VEGF and PDGF will be dispersed in PEG-PLA hydrogels and tested for stimulation of angiogenesis.