Morphology and Enzymatic Degradation of Oriented Thin Film of Ultrahigh Molecular Weight Poly[(R)-3-hydroxybutyrate]
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- 作者：Masahiro Fujita ; Yoshitaka Takikawa ; Shinya Teramachi ; Yoshihiro Aoyagi ; Tomohiro Hiraishi ; and Yoshiharu Doi
- 刊名：Biomacromolecules
- 出版年：2004
- 出版时间：September 2004
- 年：2004
- 卷：5
- 期：5
- 页码：1787 - 1791
- 全文大小：249K
- 年卷期：v.5,no.5(September 2004)
- ISSN：1526-4602
文摘
Thin films of ultrahigh molecular weight poly[(R)-3-hydroxybutyrate] (P(3HB)) were sheared and isothermallycrystallized at 100 
C. Transmission electron microscopy and atomic force microscopy (AFM) observationsrevealed that thick fibrous textures, on which lamellae are overgrown normal to the long axis of the fibril,run parallel to the shearing direction. A selected area electron diffraction pattern taken from the fibrilsexhibits a fiber pattern of P(3HB) 
-modification, and the crystallographic c-axis (chain axis) of P(3HB) isset parallel to the long axis of the fibril. In situ AFM observations of enzymatic degradation for the thinfilm were performed with an extracellular P(3HB) depolymerase from Ralstonia pickettii T1 in a buffersolution. The film surface and thickness became rougher and thinner, respectively, with time after addingthe enzyme. During the degradation, fine shish-kebab structures appeared gradually. This fact supports thatthe amorphous region in the film is preferentially degraded rather than the crystalline one by the depolymerase.The in situ AFM observations also revealed that one thick fibril in the original film is composed of threedifferent states, namely, finer fibril (shish), stacked lamellae (kebab) in edge-on state, and the surroundingamorphous phase.
C. Transmission electron microscopy and atomic force microscopy (AFM) observationsrevealed that thick fibrous textures, on which lamellae are overgrown normal to the long axis of the fibril,run parallel to the shearing direction. A selected area electron diffraction pattern taken from the fibrilsexhibits a fiber pattern of P(3HB) -modification, and the crystallographic c-axis (chain axis) of P(3HB) isset parallel to the long axis of the fibril. In situ AFM observations of enzymatic degradation for the thinfilm were performed with an extracellular P(3HB) depolymerase from Ralstonia pickettii T1 in a buffersolution. The film surface and thickness became rougher and thinner, respectively, with time after addingthe enzyme. During the degradation, fine shish-kebab structures appeared gradually. This fact supports thatthe amorphous region in the film is preferentially degraded rather than the crystalline one by the depolymerase.The in situ AFM observations also revealed that one thick fibril in the original film is composed of threedifferent states, namely, finer fibril (shish), stacked lamellae (kebab) in edge-on state, and the surroundingamorphous phase.