Tissue-adhesive and highly mechanical double-network hydrogel for cryopreservation and sustained release of anti-cancer drugs

Applications of hydrogels served as drug carriers are severely limited by several main drawbacks of instable network structure, weak mechanical strength, shortage of tissue-adhesive ability, as well as poor anti-frozen performance, especially for some anti-cancer drugs (e.g., lomustine) those should be stored at subzero temperature to maintain their bioactivity. In the present work, a kind of hybrid polyacrylamide/alginate-CaCl2 (PAAm/Alg-Ca) based double-network (DN) hydrogel presented high tensile strength of 61.81 ​± ​5.14 ​kPa, a low water contact angle of 22.5° ​± ​0.8°, and sufficient adhesion on various wet substrates (234.56 ​± ​8.55 ​Pa). More interestingly, pH-responsive swelling behavior, excellent cold-resistance, as well as efficient recoverability at a low temperature of −20 ​°C was shown in such hydrogel. On the basis of biocompatibility result and a sustained drug release behavior using lomustine as a testing model, our proposed PAAm/Alg-Ca based DN hydrogel paves the way for development of anti-cancer drugs cryopreservation and delivery vehicle.