Laser micro-patterning of biodegradable polymer blends for tissue engineering

• Published in: Journal of materials science 2015-01, Vol.50 (2), p.923-936
• Main Authors: Paun, Irina Alexandra, Zamfirescu, Marian, Mihailescu, Mona, Luculescu, Catalin Romeo, Mustaciosu, Cosmin Catalin, Dorobantu, Ion, Calenic, Bogdan, Dinescu, Maria
• Format: Article
• Language: English
• Subjects: Adhesion tests; Anchoring; Biodegradability; Biodegradable materials; Cell adhesion; Cell adhesion & migration; Characterization and Evaluation of Materials; Chemical composition; Chemical synthesis; Chemistry and Materials Science; Classical Mechanics; Crystallography and Scattering Methods; Femtosecond pulsed lasers; Glycolic acid; Hyaluronic acid; Hydroxyapatite; Immobilization; Laser ablation; Laser processing; Lasers; Materials Science; Microchannels; Original Paper; Plutonium; Polyethylene glycol; Polymer blends; Polymer industry; Polymer Sciences; Polyols; Polyurethane resins; Polyurethanes; Protein adsorption; Pulsed lasers; Solid Mechanics; Stem cells; Substrates; Thin films; Tissue engineering
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-014-8652-y

We propose a multistep all laser, maskless, and solvent free synthesis of micro-patterned substrates of biodegradable polymer blends, with applicability for guided cell adhesion and localized hyaluronic acid (HA) immobilization. The polymer blends comprised polyurethane (PU), poly(lactic-co-glycolic acid) (PLGA), and polylactide-polyethylene glycol-polylactide (PPP) in 1:1:1 blending ratios. Polymer patterning was performed by laser processing in two steps. First, the polymers were patterned with periodic micro-channels by direct femtosecond laser ablation, which provided flexibility in design and spatial accuracy for the patterns. As a second step, the micro-patterned polymers were coated with thin layers of polymer blends using matrix assisted pulsed laser evaporation (MAPLE). The resulted sandwich substrates were composed of a bottom, micro-patterned layer and thin, top layer which conserved the patterns from the underlying layer and preserved the polymers chemical composition. Depending on the bottom/top layers, the substrates were denominated PU/PU:PLGA:PPP and PU:PLGA:PPP/PU:PLGA:PPP, respectively. The laser generated micro-patterns were used for selective attachment of oral keratinocyte stem cells and for HA immobilization. The highest cellular density was found on the PU:PLGA:PPP/PU:PLGA:PPP substrate, where the spongy-like micro-channels provided multiple anchoring points for the cells. For both substrates, the micro-channels enabled localized immobilization of HA. The effectiveness of HA immobilization was tested against cell adhesion and protein adsorption.