TY - JOUR A1 - Friess, Fabian A1 - Wischke, Christian A1 - Behl, Marc A1 - Lendlein, Andreas T1 - Oligo(epsilon-caprolactone)-based polymer networks prepared by photocrosslinking in solution JF - Journal of applied biomaterials & functional materials N2 - Purpose: Polymer networks with adjustable properties prepared from endgroup-functionalized oligoesters by UV-crosslinking in melt have evolved into versatile multifunctional biomaterials. In addition to the molecular weight or architecture of precursors, the reaction conditions for crosslinking are pivotal for the polymer network properties. Crosslinking of precursors in solution may facilitate low-temperature processes and are compared here to networks synthesized in melt. Methods: Oligo(epsilon-caprolactone)-(z) methacrylate (oCL-(z) IEMA) precursors with a linear (z = di) or a four-armed star-shaped (z = tetra) architecture were crosslinked by radical polymerization in melt or in solution with UV irradiation. The thermal, mechanical, and swelling properties of the polymer networks obtained were characterized. Results: Crosslinking in solution resulted in materials with lower Young's moduli (E), lower maximum stress (sigma(max)), and higher elongation at break (epsilon(B)) as determined at 70 degrees C. Polymer networks from 8 kDa star-shaped precursors exhibited poor elasticity when synthesized in the melt, but can be established as stretchable materials with a semi-crystalline morphology, a high gel-content, and a high elongation at break when prepared in solution. Conclusions: The crosslinking condition of methacrylate functionalized precursors significantly affected network properties. For some types of precursors such as star-shaped telechelics, synthesis in solution provided semi-crystalline elastic materials that were not accessible from crosslinking in melt. KW - Crosslinking KW - Methacrylate KW - Multifunctional polyester networks KW - Poly(epsilon-caprolactone) KW - Polymer network properties Y1 - 2012 U6 - https://doi.org/10.5301/JABFM.2012.10372 SN - 2280-8000 VL - 10 IS - 3 SP - 273 EP - 279 PB - Wichtig CY - Milano ER - TY - JOUR A1 - Friess, Fabian A1 - Roch, Toralf A1 - Seifert, Barbara A1 - Lendlein, Andreas A1 - Wischke, Christian T1 - Phagocytosis of spherical and ellipsoidal micronetwork colloids from crosslinked poly(epsilon-caprolactone) JF - International Journal of Pharmaceutics N2 - The effect of non-spherical particle shapes on cellular uptake has been reported as a general design parameter to control cellular recognition of particulate drug carriers. Beside shape, also size and cell-particle ratio should mutually effect phagocytosis. Here, the capability to control cellular uptake of poly(epsilon-caprolactone) (PCL) based polymer micronetwork colloids (MNC), a carrier system that can be transferred to various shapes, is explored in vitro at test conditions allowing multiple cell-particle contacts. PCL-based MNC were synthesized as spheres with a diameter of similar to 6, similar to 10, and 13 mu m, loaded with a fluorescent dye by a specific technique of swelling, redispersion and drying, and transferred into different ellipsoidal shapes by a phantom stretching method. The boundaries of MNC deformability to prolate ellipsoid target shapes were systematically analyzed and found to be at an aspect ratio AR of similar to 4 as obtained by a phantom elongation epsilon(ph) of similar to 150%. Uptake studies with a murine macrophages cell line showed shape dependency of phagocytosis for selected conditions when varying particle sizes (similar to 6 and 10 mu m),and shapes (epsilon(ph): 0, 75 or 150%), cell-particle ratios (1:1, 1:2, 1:10, 1:50), and time points (1-24 h). For larger-sized MNC, there was no significant shape effect on phagocytosis as these particles may associate with more than one cell, thus increasing the possibility of phagocytosis by any of these cells. Accordingly, controlling shape effects on phagocytosis for carriers made from degradable polymers relevant for medical applications requires considering further parameters besides shape, such as kinetic aspects of the exposure and uptake by cells. KW - Particle shape KW - Phagocytosis KW - Macrophage KW - Polymer micronetwork colloids KW - Poly(epsilon-caprolactone) Y1 - 2019 U6 - https://doi.org/10.1016/j.ijpharm.2019.118461 SN - 0378-5173 SN - 1873-3476 VL - 567 PB - Elsevier CY - Amsterdam ER -