Surface modification of copolymerized films from three-armed biodegradable macromers – An analytical platform for modified tissue engineering scaffolds

Autor: Benno Müller, Friederike Zühl, Michael C. Hacker, Liv Kalbitzer, Peter-Georg Hoffmeister, Rudi Loth, Michaela Schulz-Siegmund
Rok vydání: 2017
Předmět:
0301 basic medicine
Materials science
Polymers
Surface Properties
Biomedical Engineering
Biocompatible Materials
02 engineering and technology
Microscopy
Atomic Force
Biochemistry
Cell Line
Polyethylene Glycols
Polymerization
Biomaterials
Contact angle
03 medical and health sciences
chemistry.chemical_compound
Polymer chemistry
Cell Adhesion
Copolymer
Animals
Humans
Molecular Biology
Fluorescent Dyes
chemistry.chemical_classification
Tissue Engineering
Tissue Scaffolds
Stem Cells
Succinic anhydride
Biomaterial
General Medicine
Polymer
Enzymes
Immobilized
021001 nanoscience & nanotechnology
030104 developmental biology
Adipose Tissue
Chemical engineering
chemistry
Solvents
Methacrylates
Surface modification
Cattle
Wetting
0210 nano-technology
Hydrophobic and Hydrophilic Interactions
Oligopeptides
Ethylene glycol
Biotechnology
Zdroj: Acta Biomaterialia. 51:148-160
ISSN: 1742-7061
DOI: 10.1016/j.actbio.2017.01.018
Popis: The concept of macromers allows for a broad adjustment of biomaterial properties by macromer chemistry or copolymerization. Copolymerization strategies can also be used to introduce reactive sites for subsequent surface modification. Control over surface features enables adjustment of cellular reactions with regard to site and object of implantation. We designed macromer-derived polymer films which function as non-implantable analytical substrates for the investigation of surface properties of equally composed scaffolds for bone tissue engineering. To this end, a toolbox of nine different biodegradable, three-armed macromers was thermally cross-copolymerized with poly(ethylene glycol)-methacrylate (PEG-MA) to films. Subsequent activation of PEG-hydroxyl groups with succinic anhydride and N -hydroxysuccinimid allowed for covalent surface modification. We quantified the capacity to immobilize analytes of low (amino-functionalized fluorescent dye, Fcad, and RGD-peptides) and high (alkaline phosphatase, ALP) molecular weight. Fcad grafting level was controlled by macromer chemistry, content and molecular weight of PEG-MA, but also the solvent used for film synthesis. Fcad molar amount per surface area was twentyfive times higher on high-swelling compared to low-swelling films, but differences became smaller when large ALP (appr. 2:1) were employed. Similarly, small differences were observed on RGD peptide functionalized films that were investigated by cell adhesion studies. Presentation of PEG-derivatives on surfaces was visualized by atomic force microscopy (AFM) which unraveled composition-dependent domain formation influencing fluorescent dye immobilization. Surface wetting characteristics were investigated via static water contact angle. We conclude that macromer ethoxylation and lactic acid content determined film swelling, PEG domain formation and eventually efficiency of surface decoration. Statement of Significance Surfaces of implantable biomaterials are the site of interaction with a host tissue. Accordingly, modifications in the composition of the surface will determine cellular response towards the material which is crucial for the success of innovations and control of tissue regeneration. We employed a macromer approach which is most flexible for the design of biomaterials with a broad spectrum of physicochemical characteristics. For ideal analytical accessibility of the material platform, we cross-copolymerized films on solid supports. Films allowed for the covalent immobilization of fluorescent labels, peptides and enzymes and thorough analytical characterization revealed that macromer hydrophilicity is the most relevant design parameter for surface analyte presentation in these materials. All analytical results were combined in a model describing PEG linker domain formation and ligand presentation.
Databáze: OpenAIRE
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