“…Increased wettability, mineralization, attachment, and proliferation of bone marrow stromal cell and chondrocytes [66][67][68][69][70][71][72] PHB, PHBHHx O 2 or air -Increased crystallinity, brittleness, biodegradability, and growth of L929 [74][75][76] Plasma treatment PHBV O 2 plasma Ester, carboxyl, carbonyl Increased hydrophilicity, but maintained only 3-4 months; increased roughness and degradation; increased ALP activity of osteoblasts; increased reattachment of D407 cells [79][80][81][82][83][84] PHBV N 2 plasma CN, CN, CONH Increased hydrophilicity, roughness, and attachment of Vero [85][86][87] PHB, PHBV NH 3 plasma Amino, amide Increased hydrophilicity with a long term stability [88,89] PHBV CO 2 plasma Carbonylic, carboxylic Increased hydrophilicity, roughness, and degradation [90] PHO Air plasma (acrylamide) Amide Increased hydrophilicity [91] PHB, PHBV Allylamine, PEG, and ethylenediamine plasma -Increased cellular resistance; decreased crystal growth [92][93][94] [95] PHB, P3HB4HB Ar plasma (acrylic acid) Carboxylic Increased surface polarity, adhesion, and proliferation of NIH 3T3 cell; decreased biodegradability [96,97] PHB, PHBV Perfluorocarbon plasma CF Decreased surface hydrophilicity and biodegradation [98][99][100] γRadiation graft polymerization is an effective and eco nomical treatment for surface modification. Usually, the grafting percentage depended on differences in regularity in the crystalline regions or crystallinity, and rate of radical decay that corresponded well to radical consumption in graft polym erization.…”