Dually responsive biodegradable drug releasing 3D printed structures

The aim of this study was to develop temperature and pH-responsive biodegradable 3D printed drug-releasing constructs using the Digital Light Processing (DLP) printing technique. The printable molecules, named “inks” throughout this study, comprised polyethylene oxide–polypropylene oxide–polyethylene oxide (PEO–PPO–PEO) triblocks and acrylic acid (AAc) that rendered them reverse thermo-responsive (RTR) and pH-sensitive, respectively. Additionally, the inks' biodegradability was imparted to them by incorporating lactide (LA) and ε-caprolactone (CL) units into their composition, while their printability was achieved by end-capping them with 2-Isocyanatoethyl methacrylate (IEMA). By fine tuning the LA/CL composition, a broad range of inks displaying different water absorption behavior, biodegradation as well as bovine serum albumin (BSA) release profiles at different conditions. All the hydrogels showed a fast and reversible swelling–deswelling response, as they fluctuated between pH 2.0 and pH 7.4 or between 10 and 37°C. The resultant hydrogels showed good water uptake capacity (6340%) at pH 7.4 and 10°C temperature. BSA release from the loaded 3D printed hydrogel showed a maximum (80.5%) at pH 7.4 and 10°C in comparison to pH 7.4 and 37°C (65%). The proposed dual responsive 3D printed biodegradable hydrogels objects will shed light as a drug carrier.