TY  - JOUR
A1  - Tarazona, Natalia A.
A1  - Machatschek, Rainhard Gabriel
A1  - Lendlein, Andreas
T1  - Influence of depolymerases and lipases on the degradation of polyhydroxyalkanoates determined in Langmuir degradation studies
JF  - Advanced materials interfaces
N2  - Microbially produced polyhydroxyalkanoates (PHAs) are polyesters that are degradable by naturally occurring enzymes. Albeit PHAs degrade slowly when implanted in animal models, their disintegration is faster compared to abiotic hydrolysis under simulated physiological environments. Ultrathin Langmuir-Blodgett (LB) films are used as models for fast in vitro degradation testing, to predict enzymatically catalyzed hydrolysis of PHAs in vivo. The activity of mammalian enzymes secreted by pancreas and liver, potentially involved in biomaterials degradation, along with microbial hydrolases is tested toward LB-films of two model PHAs, poly(3-R-hydroxybutyrate) (PHB) and poly[(3-R-hydroxyoctanoate)-co-(3-R-hydroxyhexanoate)] (PHOHHx). A specific PHA depolymerase fromStreptomyces exfoliatus, used as a positive control, is shown to hydrolyze LB-films of both polymers regardless of their side-chain-length and phase morphology. From amorphous PHB and PHOHHx, approximate to 80% is eroded in few hours, while mass loss for semicrystalline PHB is 25%. Surface potential and interfacial rheology measurements show that material dissolution is consistent with a random-chain-scission mechanism. Degradation-induced crystallization of semicrystalline PHB LB-films is also observed. Meanwhile, the surface and the mechanical properties of both LB-films remain intact throughout the experiments with lipases and other microbial hydrolases, suggesting that non-enzymatic hydrolysis could be the predominant factor for acceleration of PHAs degradation in vivo.
KW  - enzymatic-degradation
KW  - Langmuir thin-films
KW  - lipases
KW  - PHA-depolymerases
KW  - polyhydroxyalkanoates (PHA)
Y1  - 2020
U6  - https://doi.org/10.1002/admi.202000872
SN  - 2196-7350
VL  - 7
IS  - 17
PB  - Wiley
CY  - Hoboken
ER  -