A Preliminary Study Of The Light Intensity Influence On 4D Printed Temperature-Responsive Nipam Based Hydrogels

—4D printing managed to overcome some of the limitations of its predecessor, the 3D printing process, by replacing rigid structures with structures capable of changing their shape over time. The responsive nature of the 4D printed structures is of interest to several areas, including tissue engineering, which aims to restore, maintain, and improve damaged tissues or whole organs. Among the range of materials commercially available, poly (N-isopropyl acrylamide) (NIPAM) stands out as a thermo-responsive polymer compatible with different cell cultures. As much as there is already some consolidated knowledge about the material, there is still a lot to be explored in terms of 4D bioprinting technologies capable of efficiently generating NIPAM thermo-responsive structures. This work explores the impact of light incidence on a NIPAM based hydrogel to be processed by digital light processing (DLP). With the aid of a power meter, tests were performed regarding the variation of luminosity incident on the hydrogel. It was concluded that a waiting time of 20 minutes is necessary until the light source reaches a steady state of light intensity supply, and the ideal energy intensity for polymerization of a NIPAM based hydrogel using Irgacure 2959 as a photoinitiator is approximately 22mW.