Western blot analysis of GST-B7-2-PhaP fusion protein immobilized on the surface of PHBHHx nanoparticles. Lanes 1-2: the original GST-B7-2-PhaP protein samples with an initial concentration of 2 and 2.5 mg ml-1, respectively. Lanes 3-4: GST-B7-2-PhaP protein eluted from the surface of PHBHHx nanoparticles after the immobilization procedure. Lanes 5-6: the remnant GST-B7-2-PhaP proteins remaining in the supernatant after the immobilization procedure. The concentration of the initial protein sample of Lanes 3 and 5 was 2 mg ml-1, and that of Lanes 4 and 6 was 2.5 mg ml-1. Protein weight marker (Institute of Biochemistry and Cell Biology, SIBS, CAS, China) was loaded in lane M, which was not detected by western blot analysis.