TY - JOUR A1 - Izraylit, Victor A1 - Liu, Yue A1 - Tarazona, Natalia A. A1 - Machatschek, Rainhard Gabriel A1 - Lendlein, Andreas T1 - Crystallization and degradation behaviour of multiblock copolyester blends in Langmuir monolayers JF - MRS communications / a publication of the Materials Research Society N2 - Supporting the wound healing of soft tissues requires fixation devices becoming more elastic while degrading. To address this unmet need, we designed a blend of degradable multiblock copolymers, which is cross-linked by PLA stereocomplexation combining two soft segments differing substantially in their hydrolytic degradation rate. The degradation path and concomitant structural changes are predicted by Langmuir monolayer technique. The fast hydrolysis of one soft segment leads to a decrease of the total polymer mass at constant physical cross-linking density. The corresponding increase of the average spacing between the network nodes suggests the targeted increase of the blend's flexibility. KW - Degradable KW - In situ KW - Microstructure KW - Thin film Y1 - 2021 U6 - https://doi.org/10.1557/s43579-021-00107-y SN - 2159-6859 SN - 2159-6867 VL - 11 IS - 6 SP - 850 EP - 855 PB - Springer CY - Berlin ER - 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 - TY - JOUR A1 - Lendlein, Andreas A1 - Balk, Maria A1 - Tarazona, Natalia A. A1 - Gould, Oliver E. C. T1 - Bioperspectives for Shape-Memory Polymers as Shape Programmable, Active Materials JF - Biomacromolecules : an interdisciplinary journal focused at the interface of polymer science and the biological sciences N2 - Within the natural world, organisms use information stored in their material structure to generate a physical response to a wide variety of environmental changes. The ability to program synthetic materials to intrinsically respond to environmental changes in a similar manner has the potential to revolutionize material science. By designing polymeric devices capable of responsively changing shape or behavior based on information encoded into their structure, we can create functional physical behavior, including a shape memory and an actuation capability. Here we highlight the stimuli-responsiveness and shape-changing ability of biological materials and biopolymer-based materials, plus their potential biomedical application, providing a bioperspective on shape-memory materials. We address strategies to incorporate a shape memory (actuation) function in polymeric materials, conceptualized in terms of its relationship with inputs (environmental stimuli) and outputs (shape change). Challenges and opportunities associated with the integration of several functions in a single material body to achieve multifunctionality are discussed. Finally, we describe how elements that sense, convert, and transmit stimuli have been used to create multisensitive materials. Y1 - 2019 U6 - https://doi.org/10.1021/acs.biomac.9b01074 SN - 1525-7797 SN - 1526-4602 VL - 20 IS - 10 SP - 3627 EP - 3640 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Tarazona, Natalia A. A1 - Machatschek, Rainhard Gabriel A1 - Schulz, Burkhard A1 - Auxiliadora Prieto Jiménez, M. A1 - Lendlein, Andreas T1 - Molecular Insights into the Physical Adsorption of Amphiphilic Protein PhaF onto Copolyester Surfaces JF - Biomacromolecules : an interdisciplinary journal focused at the interface of polymer science and the biological sciences N2 - Phasins are amphiphilic proteins located at the polymer-cytoplasm interface of bacterial polyhydroxyalkanoates (PHA). The immobilization of phasins on biomaterial surfaces is a promising way to enhance the hydrophilicity and supply cell- directing elements in bioinstructing processes. Optimizing the physical adsorption of phasins requires deep insights into molecular processes during polymer-protein interactions to preserve their structural conformation while optimizing surface coverage. Here, the assembly, organization, and stability of phasin PhaF from Pseudomonas putida at interfaces is disclosed. The Langmuir technique, combined with in situ microscopy and spectroscopic methods, revealed that PhaF forms stable and robust monolayers at different temperatures, with an almost flat orientation of its alpha-helix at the air-water interface. PhaF adsorption onto preformed monolayers of poly[(3-R-hydroxyoctanoate)-co-(3-R-hydroxyhexanoate)] (PHOHHx), yields stable mixed layers below pi = similar to 15.7 mN/m. Further insertion induces a molecular reorganization. PHOHHx with strong surface hydrophobicity is a more adequate substrate for PhaF adsorption than the less hydrophobic poly[(rac-lactide)-co-glycolide] (PLGA). The observed orientation of the main axis of the protein in relation to copolyester interfaces ensures the best exposure of the hydrophobic residues, providing a suitable coating strategy for polymer functionalization. Y1 - 2019 U6 - https://doi.org/10.1021/acs.biomac.9b00069 SN - 1525-7797 SN - 1526-4602 VL - 20 IS - 9 SP - 3242 EP - 3252 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Tarazona, Natalia A. A1 - Machatschek, Rainhard Gabriel A1 - Lendlein, Andreas T1 - Unraveling the interplay between abiotic hydrolytic degradation and crystallization of bacterial polyesters comprising short and medium side-chain-length Polyhydroxyalkanoates JF - Biomacromolecules : an interdisciplinary journal focused at the interface of polymer science and the biological sciences N2 - Polyhydroxyalkanoates (PHAs) have attracted attention as degradable (co)polyesters which can be produced by microorganisms with variations in the side chain. This structural variation influences not only the thermomechanical properties of the material but also its degradation behavior. Here, we used Langmuir monolayers at the air-water (A-W) interface as suitable models for evaluating the abiotic degradation of two PHAs with different side-chain lengths and crystallinity. By controlling the polymer state (semi crystalline, amorphous), the packing density, the pH, and the degradation mechanism, we could draw several significant conclusions. (i) The maximum degree of crystallinity for a PHA film to be efficiently degraded up to pH = 12.3 is 40%. (ii) PHA made of repeating units with shorter side-chain length are more easily hydrolyzed under alkaline conditions. The efficiency of alkaline hydrolysis decreased by about 65% when the polymer was 40% crystalline. (iii) In PHA films with a relatively high initial crystallinity, abiotic degradation initiated a chemicrystallization phenomenon, detected as an increase in the storage modulus (E'). This could translate into an increase in brittleness and reduction in the material degradability. Finally, we demonstrate the stability of the measurement system for long-term experiments, which allows degradation conditions for polymers that could closely simulate real-time degradation. Y1 - 2019 U6 - https://doi.org/10.1021/acs.biomac.9b01458 SN - 1525-7797 SN - 1526-4602 VL - 21 IS - 2 SP - 761 EP - 771 PB - American Chemical Society CY - Washington ER -