Surface modification of polyimide sheets for regenerative medicine applications

In the present work, two strategies were elaborated to surface-functionalize implantable polyimide sheets. In the first methodology, cross-linkable vinyl groups were introduced on the polyimide surface using aminopropylmethacrylamide. In the second approach, arc:active succinimidyl ester was introduced on the surface of PI. Using the former approach, the aim is to apply a vinyl functionalized biopolymer coating. In the latter approach, any amine containing biopolymer can be immobilized. The foils developed were characterized in depth using a variety of characterization techniques. including atomic force rnicroscopy, static contact angle measurements, and X-ray photoelectron spectroscopy. The results indicated that both modification strategies were successful. The subcutaneous implantation in mice indicated that both modification strategies resulted in biocompatible materials, inducing only limited cellular infiltration to the surrounding tissue

Chimera of IL‑2 Linked to Light Chain of anti-IL‑2 mAb Mimics IL-2/anti-IL‑2 mAb Complexes Both Structurally and Functionally

IL-2/anti-IL-2 mAb immunocomplexes were described to have dramatically higher activity than free IL-2 <i>in vivo</i>. We designed protein chimera consisting of IL-2 linked to light chain of anti-IL-2 mAb S4B6 through flexible oligopeptide spacer (Gly₄Ser)₃. This protein chimera mimics the structure of IL-2/S4B6 mAb immunocomplexes but eliminates general disadvantages of immunocomplexes like possible excess of either IL-2 or anti-IL-2 mAb and their dissociation to antibody and IL-2 at low concentrations. This novel kind of protein chimera is characterized by an intramolecular interaction between IL-2 and binding site of S4B6 mAb similarly as in IL-2/S4B6 mAb immunocomplexes. Our protein chimera has biological activity comparable to IL-2/S4B6 mAb immunocomplexes <i>in vitro</i>, as shown by stimulation of proliferation of purified and activated OT-I CD8⁺ T cells. The protein chimera exerts higher stimulatory activity to drive expansion of purified CFSE-labeled OT-I CD8⁺ T cells activated by an injection of a low dose of SIINFEKL peptide than IL-2/S4B6 mAb immunocomplexes <i>in vivo</i>