title: Direct laser writing of synthetic poly(amino acid) hydrogels and poly(ethylene glycol) diacrylates by two-photon polymerization.
abstract: The additive manufacturing technique of direct laser writing by two-photon polymerization (2PP-DLW) enables the fabrication of three-dimensional microstructures with superior accuracy and flexibility. When combined with biomimetic hydrogel materials, 2PP-DLW can be used to recreate the microarchitectures of the extracellular matrix. However, there are currently only a limited number of hydrogels applicable for 2PP-DLW. In order to widen the selection of synthetic biodegradable hydrogels, in this work we studied the 2PP-DLW of methacryloylated and acryloylated poly(α-amino acid)s (poly(AA)s). The performance of these materials was compared to widely used poly(ethylene glycol) diacrylates (PEGdas) in terms of polymerization and damage thresholds, voxel size, line width, post-polymerization swelling and deformation. We found that both methacryloylated and acryloylated poly(AA) hydrogels are suitable to 2PP-DLW with a wider processing window than PEGdas. The poly(AA) with the highest degree of acryloylation showed the greatest potential for 3D microfabrication.
authors.affiliation: Department of Electronics and Communications Engineering, Tampere University of Technology, P.O. Box 692, 33101 Tampere, Finland; BioMediTech, Biokatu 10, 33520 Tampere, Finland. Electronic address: elli.kapyla@tut.fi.
authors.forename: Elli
authors.initials: E
authors.lastname: Käpylä
authors.affiliation: Institute of Macromolecular Chemistry of the Academy of Sciences of the Czech Republic, Heyrovského nám. 2, 162 06 Praha 6, Břevnov, Prague, Czech Republic.
authors.forename: Tomáš
authors.initials: T
authors.lastname: Sedlačík
authors.affiliation: Department of Electronics and Communications Engineering, Tampere University of Technology, P.O. Box 692, 33101 Tampere, Finland; BioMediTech, Biokatu 10, 33520 Tampere, Finland.
authors.forename: Dogu Baran
authors.initials: DB
authors.lastname: Aydogan
authors.affiliation: VTT Technical Research Centre of Finland, P.O. Box 1300, 33101 Tampere, Finland.
authors.forename: Jouko
authors.initials: J
authors.lastname: Viitanen
authors.affiliation: Institute of Macromolecular Chemistry of the Academy of Sciences of the Czech Republic, Heyrovského nám. 2, 162 06 Praha 6, Břevnov, Prague, Czech Republic.
authors.forename: František
authors.initials: F
authors.lastname: Rypáček
authors.affiliation: Department of Electronics and Communications Engineering, Tampere University of Technology, P.O. Box 692, 33101 Tampere, Finland; BioMediTech, Biokatu 10, 33520 Tampere, Finland.
authors.forename: Minna
authors.initials: M
authors.lastname: Kellomäki
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D020100:Hydrogels; D007834:Lasers; D008855:Microscopy, Electron, Scanning; D017785:Photons; D011092:Polyethylene Glycols / Q000737:chemistry*; D058105:Polymerization
chemical_list: D000596:Amino Acids; D020100:Hydrogels; C437167:poly(ethylene glycol)diacrylate; D011092:Polyethylene Glycols
keywords: Direct laser writing; Hydrogel; Microfabrication; Poly(ethylene glycol) diacrylate; Polyamino acid; Two-photon polymerization