Biodegradable filaments, from materials such as polyglycolic acid (PGA), polylactic acid (PLA) and copolymers thereof, are used commercially in medicine for sutures, osteosynthesis and drug delivery systems as well as for meshes and tissue engineering scaffolds. In vivo hydrolytic degradation of mentioned poly(α-hydroxyacids) result in release of degradation products, which can cause local acidosis, inflammatory reactions and dramatic clinical complications, which make a second operation for implant removal necessary. Therefore, filaments with a pH-neutral degradation are desired. A promising additive for neutralization of the pH are amine based microgels because of their high proton binding capacity and high biocompatibility. These pH-responsive colloidal polymer networks are heat sensitive and therefore have to be incorporated into filaments using solution spinning (e.g. dry or wet spinning).

Wet spinning of PLGA multifilament’s with up to 10 wt.-% of microgels were successful. The incorporation of microgels results in significant changes in the filament morphology and to a significant decrease in tensile strength of the filaments. Nevertheless, production of braided, woven and knitted structures from the multifilaments was possible.