Monodisperse Polymer Foams for Tissue Engineering

Porous materials via templating routes


In clinical applications, like in accident surgery or orthopedics, the occurrence of not self-healing bone defects caused by a congenital deformity or a tumor resection, have to be artificially reconstructed with suitable materials. [1] [2] Polymer foams have a high potential to serve as scaffolds for the growth of tissue. Especially suitable for this application are biodegradable polymer foams, in general and foams based on propylene fumarate dimethacrylate (PFDMA) in particular. Scaffolds for tissue engineering are required to be three dimensional, interconnected and highly porous. [2] The interconnection of pores are fundamental for a successful supply of nutrients to the cell to ensure tissue growth. [3] Depending on the clinical application the morphology of the polymer foams can be tailored, for instance, the porosity as well as the pore size distribution can be adjusted accordingly. [4] Focus of this PhD-Thesis is the synthesis of monodisperse poly-PFDMA foams for the application in tissue engineering. For this purpose, the microfluidic technique will be used for the generation of either monodisperse liquid foamed emulsion templates (PFDMA-in-water emulsions) or monodisperse liquid emulsion templates (water-in-PFDMA emulsion). The polymerization of the templates is supposed to lead to polymer foams with the same structure. The templates are generated by a simultaneous injection of the dispersed (gas or water) and the continuous phase under pressure via a constriction in the microfluidic chip geometry. The resulting monodisperse bubbles and droplets, respectively are stabilized by a surfactant. The template structures can be changed by changing the chip geometry or modifying the flow rates of the dispersed or the continuous phase. This allows producing different bubble or droplet sizes and thus different pore sizes of the polymer foam. [5] Schematic drawings of the microfluidic device as well as both templating routes are shown in Figure 1.

Figure 1 Schematic drawing of a section of the microfluidic device for the generation of foamed emulsions (left) and emulsions (right) (Redrawn and modified from [5]).
[1] Knochen-Tissue-Engineering in der klinischen Anwendung, P. Bernstein, M. Bornhäuser, K. -P. Günther, M. Stiehler, Der Orthopäde, 2009, 38,1029-1037.
[2] Injectable PolyHIPEs as High-Porosity Bone Grafts, R. S. Moglia, J. L. Holm, N. A. Sears, C. J. Wilson, D. M. Harrison, E. Cosgriff-Hernandez, Biomacromolecules, 2011, 12,3621-3628.
[3] Achieving Interconnected Pore Architecture in Injectable PolyHIPEs for Bone Tissue Engineering, J. L. Robinson, R. S. Moglia, M. C. Stuebben, M. A. P. McEnery, E. Cosgriff-Hernandez, Tissue Engineering: Part A, 2014, 20,1103-1112.
[4] Correlation between porous texture and cell seeding efficiency of gas foaming and microfluidic foaming scaffolds, M. Constantini, C. Colosi, P. Mozetic, J. Jaroszewicz, A. Tosato, A. Rainer, M. Trombetta, W. Święszkowski, M. Dentini, A. Barbetta, Materials Science and Engineering C, 2016, 62,668-667.
[5] Monodisperse Polystyrene Foams via Microfluidics – A Novel Templating Route, A. Quell, J. Elsing, W. Drenckhan, C. Stubenrauch, Adv. Eng. Mat., 2015, 17, 604-609.
This picture showsMiriam Dabrowski

Miriam Dabrowski

PhD Student

This picture showsCosima Stubenrauch
Prof. Dr.

Cosima Stubenrauch

Dean of Faculty

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