Poly 3-hydroxyoctanoate-co-3-hydroxyhexanoate

In order to develop a tissue-engineered heart valve, a group at Children s Hospital in Boston evaluated several synthetic absorbable polyesters as potential scaffolding materials for heart valves. Unfoitu-nately, the most synthetic polyesters proved to be too stiff to be function as flexible leaflets inside a tri-leaflet valve. " In the late 1990s, a much more flexible PHAs called poly-3-hydroxyoctanoate-co-3-hydroxyhexanoate (PHO) was used as the scaffold material for the valve leaflet, and then the entire heart valve. ... 

Injectable liquid polyhydroxyalkanoate compositions consisting of the transesterification product of poly(3-hydroxyoctanoate-co-3-hydroxyhexanoate) with 1,3-butanediol were prepared by Williams et al. (3) and used in soft tissue repair, augmentation, and viscosupplementation in humans. 

P3HB-3HV Poly(3-hydrox5d)utyrate-co-3-hydroxyvalerate) P3HB-4HB Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) P3HB-3HH Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) P3HO-3HH Poly(3-hydroxyoctanoate-co-3-hydroxyhexanoate) P3HU Poly(3-hydroxyundecenoate)... 

Moreover, P3HB shows a crystalline structure because of its stereoregularity similarity to isotactic polypropylene. In order to improve mechanical properties and processability, and thus to obtain a more flexible material, P3HB copolymers are nowadays used. The first attempt to synthesize a random copolymer is a blend of 3-hydroxybutanoic acid and 3-hydroxyvaleric acid, obtaining poly(3-hydroxybutyrate-co-3-hydroxyvalerate) P(3HB-co-3HV) copolymer. Other blends are obtained using, for example, hydroxyhexanoic acid, 4-hydroxybutanoic acid, and hydroxyoctanoic acid. Physical and mechanical properties of these copolymers have been reported (Lee and Park, 2005, Marchessault and Yu, 2005, Williams and Martin, 2005) as well... 

PHB-co-PHV [54] is obtained from Azotobacter chroococcum [58, 63). The biodegradation is slower for the copolymers than poly-3-hydroxybutyrate. 3-hydroxy-n-phenylalkanoic acids and 3-hydroxyaliphatic acids are obtained from Pseudomonas putida [59]. Poly (3-hydroxyoctanoic acid) and poly (6-hydroxyhexanoic acid) and poly (3-hydroxyoctanoic acid) [64], Poly-(R)-3-hydroxybutyrate/polyphosphate (PHB/polyP) complexes are isolated from the plasma membranes of bacteria [65,66]. Polyhydroxyoctanoate is produced by feeding octanoic acid to Pseudomonas oleovorans [67]. 

Chen ZF, Cheng ST, Xu KT. Block Poly(ester-urethane)s based on poly(3-hydroxybu-tyrate-co-4-hydroxybutyrate) and poly(3-hydroxyhexanoate-co-3-hydroxyoctanoate). Biomaterials 2009 30(12) 2219-30. 

Procter Sc Gamble developed a wide range of poly(hydroxybutyrate-co-hydroxyalkanoates) [copolymers of P(3HB) and 3-hydroxyhexanoate, P(3HB) and 3-hydroxyoctanoate, P(3HB) and 3-hydroxyoctadecanoate] with the tradename Nodax. In 2007, Meredian Inc. purchased Procter Sc Gamble s PHA technology. Meredian Inc. has announced the start-up of production at full industrial level (30 ktonnes/year) in its Bainbridge facility in the second half of 2014 [21]. 

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