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Fundamental insights in PLGA degradation from thin film studies. J Control Release 2019; 319:276-284. [PMID: 31884098 DOI: 10.1016/j.jconrel.2019.12.044] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 12/20/2019] [Accepted: 12/26/2019] [Indexed: 01/18/2023]
Abstract
Poly(lactide-co-glycolide)s are commercially available degradable implant materials, which are typically selected based on specifications given by the manufacturer, one of which is their molecular weight. Here, we address the question whether variations in the chain length and their distribution affect the degradation behavior of Poly[(rac-lactide)-co-glycolide]s (PDLLGA). The hydrolysis was studied in ultrathin films at the air-water interface in order to rule out any morphological effects. We found that both for purely hydrolytic degradation as well as under enzymatic catalysis, the molecular weight has very little effect on the overall degradation kinetics of PDLLGAs. The quantitative analysis suggested a random scission mechanism. The monolayer experiments showed that an acidic micro-pH does not accelerate the degradation of PDLLGAs, in contrast to alkaline conditions. The degradation experiments were combined with interfacial rheology measurements, which showed a drastic decrease of the viscosity at little mass loss. The extrapolated molecular weight behaved similar to the viscosity, dropping to a value near to the solubility limit of PDLLGA oligomers before mass loss set in. This observation suggests a solubility controlled degradation of PDLLGA. Conclusively, the molecular weight affects the degradation of PDLLGA devices mostly in indirect ways, e.g. by determining their morphology and porosity during fabrication. Our study demonstrates the relevance of the presented Langmuir degradation method for the design of controlled release systems.
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Tarazona NA, Machatschek R, Schulz B, Prieto MA, Lendlein A. Molecular Insights into the Physical Adsorption of Amphiphilic Protein PhaF onto Copolyester Surfaces. Biomacromolecules 2019; 20:3242-3252. [DOI: 10.1021/acs.biomac.9b00069] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Natalia A. Tarazona
- Institute of Biomaterial
Science and Berlin-Brandenburg Center for Regenerative Therapies, Helmholtz-Zentrum Geesthacht, Kantstraße 55, 14513 Teltow, Germany
- Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Rainhard Machatschek
- Institute of Biomaterial
Science and Berlin-Brandenburg Center for Regenerative Therapies, Helmholtz-Zentrum Geesthacht, Kantstraße 55, 14513 Teltow, Germany
| | - Burkhard Schulz
- Institute of Biomaterial
Science and Berlin-Brandenburg Center for Regenerative Therapies, Helmholtz-Zentrum Geesthacht, Kantstraße 55, 14513 Teltow, Germany
- Institute of Chemistry, University of Potsdam, Karl-Liebknecht-Straße 24-25, 14469 Potsdam, Germany
| | - M. Auxiliadora Prieto
- Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Andreas Lendlein
- Institute of Biomaterial
Science and Berlin-Brandenburg Center for Regenerative Therapies, Helmholtz-Zentrum Geesthacht, Kantstraße 55, 14513 Teltow, Germany
- Institute of Chemistry, University of Potsdam, Karl-Liebknecht-Straße 24-25, 14469 Potsdam, Germany
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Machatschek R, Schulz B, Lendlein A. Langmuir Monolayers as Tools to Study Biodegradable Polymer Implant Materials. Macromol Rapid Commun 2018; 40:e1800611. [PMID: 30387219 DOI: 10.1002/marc.201800611] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 09/24/2018] [Indexed: 11/06/2022]
Abstract
Langmuir monolayers provide a fast and elegant route to analyze the degradation behavior of biodegradable polymer materials. In contrast to bulk materials, diffusive transport of reactants and reaction products in the (partially degraded) material can be neglected at the air-water interface, allowing for the study of molecular degradation kinetics in experiments taking less than a day and in some cases just a few minutes, in contrast to experiments with bulk materials that can take years. Several aspects of the biodegradation behavior of polymer materials, such as the interaction with biomolecules and degradation products, are directly observable. Expanding the technique with surface-sensitive instrumental techniques enables evaluating the evolution of the morphology, chemical composition, and the mechanical properties of the degrading material in situ. The potential of the Langmuir monolayer degradation technique as a predictive tool for implant degradation when combined with computational methods is outlined, and related open questions and strategies to overcome these challenges are pointed out.
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Affiliation(s)
- Rainhard Machatschek
- Institute of Biomaterial Science and Berlin-Brandenburg Center for Regenerative Therapies, Helmholtz-Zentrum Geesthacht, Kantstraße 55,, 14513, Teltow, Germany
| | - Burkhard Schulz
- Institute of Biomaterial Science and Berlin-Brandenburg Center for Regenerative Therapies, Helmholtz-Zentrum Geesthacht, Kantstraße 55,, 14513, Teltow, Germany.,Institute of Chemistry, University of Potsdam, Karl-Liebknecht-Straße 24-25,, 14469, Potsdam, Germany
| | - Andreas Lendlein
- Institute of Biomaterial Science and Berlin-Brandenburg Center for Regenerative Therapies, Helmholtz-Zentrum Geesthacht, Kantstraße 55,, 14513, Teltow, Germany.,Institute of Chemistry, University of Potsdam, Karl-Liebknecht-Straße 24-25,, 14469, Potsdam, Germany
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Schöne AC, Roch T, Schulz B, Lendlein A. Evaluating polymeric biomaterial-environment interfaces by Langmuir monolayer techniques. J R Soc Interface 2017; 14:20161028. [PMID: 28468918 PMCID: PMC5454283 DOI: 10.1098/rsif.2016.1028] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 04/05/2017] [Indexed: 12/18/2022] Open
Abstract
Polymeric biomaterials are of specific relevance in medical and pharmaceutical applications due to their wide range of tailorable properties and functionalities. The knowledge about interactions of biomaterials with their biological environment is of crucial importance for developing highly sophisticated medical devices. To achieve optimal in vivo performance, a description at the molecular level is required to gain better understanding about the surface of synthetic materials for tailoring their properties. This is still challenging and requires the comprehensive characterization of morphological structures, polymer chain arrangements and degradation behaviour. The review discusses selected aspects for evaluating polymeric biomaterial-environment interfaces by Langmuir monolayer methods as powerful techniques for studying interfacial properties, such as morphological and degradation processes. The combination of spectroscopic, microscopic and scattering methods with the Langmuir techniques adapted to polymers can substantially improve the understanding of their in vivo behaviour.
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Affiliation(s)
- Anne-Christin Schöne
- Institute of Chemistry, University of Potsdam, Karl-Liebknecht-Strasse 24-25, 14476 Potsdam, Germany
- Institute of Biomaterial Science and Berlin-Brandenburg Centre for Regenerative Therapies (BCRT), Helmholtz-Zentrum Geesthacht, Kantstrasse 55, 14513 Teltow, Germany
| | - Toralf Roch
- Institute of Biomaterial Science and Berlin-Brandenburg Centre for Regenerative Therapies (BCRT), Helmholtz-Zentrum Geesthacht, Kantstrasse 55, 14513 Teltow, Germany
- Helmholtz Virtual Institute-Multifunctional Biomaterials for Medicine, Kantstrasse 55, 14513 Teltow, Germany
| | - Burkhard Schulz
- Institute of Chemistry, University of Potsdam, Karl-Liebknecht-Strasse 24-25, 14476 Potsdam, Germany
- Institute of Biomaterial Science and Berlin-Brandenburg Centre for Regenerative Therapies (BCRT), Helmholtz-Zentrum Geesthacht, Kantstrasse 55, 14513 Teltow, Germany
| | - Andreas Lendlein
- Institute of Chemistry, University of Potsdam, Karl-Liebknecht-Strasse 24-25, 14476 Potsdam, Germany
- Institute of Biomaterial Science and Berlin-Brandenburg Centre for Regenerative Therapies (BCRT), Helmholtz-Zentrum Geesthacht, Kantstrasse 55, 14513 Teltow, Germany
- Helmholtz Virtual Institute-Multifunctional Biomaterials for Medicine, Kantstrasse 55, 14513 Teltow, Germany
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Rottke FO, Schulz B, Richau K, Kratz K, Lendlein A. An ellipsometric approach towards the description of inhomogeneous polymer-based Langmuir layers. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2016; 7:1156-1165. [PMID: 27826490 PMCID: PMC5082346 DOI: 10.3762/bjnano.7.107] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 07/13/2016] [Indexed: 06/06/2023]
Abstract
The applicability of nulling-based ellipsometric mapping as a complementary method next to Brewster angle microscopy (BAM) and imaging ellipsometry (IE) is presented for the characterization of ultrathin films at the air-water interface. First, the methodology is demonstrated for a vertically nonmoving Langmuir layer of star-shaped, 4-arm poly(ω-pentadecalactone) (PPDL-D4). Using nulling-based ellipsometric mapping, PPDL-D4-based inhomogeneously structured morphologies with a vertical dimension in the lower nm range could be mapped. In addition to the identification of these structures, the differentiation between a monolayer and bare water was possible. Second, the potential and limitations of this method were verified by applying it to more versatile Langmuir layers of telechelic poly[(rac-lactide)-co-glycolide]-diol (PLGA). All ellipsometric maps were converted into thickness maps by introduction of the refractive index that was derived from independent ellipsometric experiments, and the result was additionally evaluated in terms of the root mean square roughness, Rq. Thereby, a three-dimensional view into the layers was enabled and morphological inhomogeneity could be quantified.
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Affiliation(s)
- Falko O Rottke
- Institute of Biomaterial Science and Berlin-Brandenburg Centre for Regenerative Therapies (BCRT), Helmholtz-Zentrum Geesthacht, Kantstraße 55, 14513 Teltow, Germany
- Institute of Chemistry, University of Potsdam, Karl-Liebknecht-Straße 24–25, 14476 Golm, Germany
| | - Burkhard Schulz
- Institute of Biomaterial Science and Berlin-Brandenburg Centre for Regenerative Therapies (BCRT), Helmholtz-Zentrum Geesthacht, Kantstraße 55, 14513 Teltow, Germany
- Institute of Chemistry, University of Potsdam, Karl-Liebknecht-Straße 24–25, 14476 Golm, Germany
| | - Klaus Richau
- Institute of Biomaterial Science and Berlin-Brandenburg Centre for Regenerative Therapies (BCRT), Helmholtz-Zentrum Geesthacht, Kantstraße 55, 14513 Teltow, Germany
| | - Karl Kratz
- Institute of Biomaterial Science and Berlin-Brandenburg Centre for Regenerative Therapies (BCRT), Helmholtz-Zentrum Geesthacht, Kantstraße 55, 14513 Teltow, Germany
| | - Andreas Lendlein
- Institute of Biomaterial Science and Berlin-Brandenburg Centre for Regenerative Therapies (BCRT), Helmholtz-Zentrum Geesthacht, Kantstraße 55, 14513 Teltow, Germany
- Institute of Chemistry, University of Potsdam, Karl-Liebknecht-Straße 24–25, 14476 Golm, Germany
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