Soft tissues are responsible for connecting and supporting different organs and other well-organized tissues in the human body. Their function decays with aging or injury and their limited regeneration capacity demands aid from tissue engineering strategies. Implantable biomedical devices must exhibit mechanical properties similar to the native tissue to promote appropriate cellular behavior and regeneration of the tissue. Given the large variety of soft tissues in the body, it is crucial that new devices show mechanical properties that can be easily tuned to fit within the requirements of a specific tissue.

Hydrogels and thin polymer networks have been demonstrated to possess properties similar to the extracellular matrix of many biological tissues, such as cartilage, which can be perceived as biological matrices with numerous physical crosslinks. A new hydrogel manufacture method that discards organic solvents was recently introduced, based on the synthesis of polyelectrolyte complexes (PECs) by ion pairing crosslinking, similar to the layer-by-layer (LbL) technique. Herein, chitosan/alginate PECs were synthesized using solutions containing a high content of sodium chloride to reduce electrostatic repulsion between ionized groups of the same charge sign, thus favoring the establishment of ionic crosslinks. PECs were then compacted into the shape of membranes by temperature-assisted drying.