Thermal degradation analysis of 3D printed scaffolds using ElastoSens™ Bio
- The evaluation of the thermoreversible behavior of specific hydrogels is conventionally performed with in-contact and destructive techniques.
- ElastoSens™ Bio characterizes thermoreversible properties through the measurement of the viscoelastic properties of thermoreversible hydrogels.
- The thermoreversible properties of gelatin and poloxamer bulk gels and 3D printed scaffolds were observed by the pronounced change in the shear storage modulus as a function of temperature.
- The structure and the concentration of the thermoreversible gels influenced the gel formation and degradation kinetics.
MATERIALS AND METHODS
RESULTS AND DISCUSSION
Fig. 3 shows the evolution in the shear storage modulus (G’) of the gelatin gels during 7 minutes at 45 °C. For both conditions (3D printed scaffold and bulk gel), the shear modulus decreased over time confirming the complete thermal degradation of the gelatin. The 3D printed construct showed a considerably lower initial G’ (15 % of the G’ from the bulk gel) which was expected since the first is a porous structure. Another noticeable difference between the two samples was the degradation rate which was substantially higher for the bulk gel implied by the steeper slope of the curve. This difference shows that the structure influences the degradation process.
Fig. 5: Shear Elastic Modulus as a function of time of 3D printed poloxamer gels at 12 °C.
— ElastoSens™ Bio allows to rapidly vary the temperature in the same test for studying the thermoreversible behavior in real time of specific polymers through their viscoelasticity.
— ElastoSens™ Bio is able to capture subtle mechanical changes during gel formation and degradation.
— The direct printing inside the sample holder of the ElastoSens™ Bio avoids the excessive manipulation of soft hydrogels which can cause sample damage and contamination.
— ElastoSens™ Bio allows testing the viscoelasticity of biomaterials under different physical (e.g. photo or thermo stimulation), chemical (e.g. crosslinking solution) and physiological (e.g. enzymatic solution) conditions to simulate in vivo behaviors.
 Hogan, K. J., & Mikos, A. G. (2020). Biodegradable thermoresponsive polymers: Applications in drug delivery and tissue engineering. Polymer, 211, 123063.
 Prendergast, M. E., Solorzano, R. D., & Cabrera, D. (2017). Bioinks for biofabrication: current state and future perspectives. Journal of 3D printing in medicine, 1(1), 49-62.
 Furth, M. E., Atala, A., & Van Dyke, M. E. (2007). Smart biomaterials design for tissue engineering and regenerative medicine. Biomaterials, 28(34), 5068-5073.
Cellularized hydrogels have been widely investigated for producing in vitro models of tissues such as skin, blood vessels, bone, etc. These models can be a valuable alternative to animal models used in trials for studying physio/pathological processes and for testing new drugs and medical devices.
The controlled release of drugs at precise locations within the body can prevent systemic toxicity and deliver accurate dosages to patients. Hydrogels have recently been investigated as promising drug delivery systems due to their ability to provide spatial and temporal control over the release of a number of therapeutic agents. Furthermore, the easy tunability of their physicochemical and mechanical properties allows the design of application-specific release systems.
Biodegradable hydrogels are promising candidates as drug carriers due to their biocompatibility and tunable degradation. This is particularly valuable for oral delivery systems since the polymer should respond to pH or enzymatic changes in the gastrointestinal environment to achieve a controlled drug release.
Hydrogels exhibit a pronounced viscoelastic behavior similar to soft tissues. For this reason, they have been widely used in biomedical research for developing engineered tissues and novel treatments such as wound dressings and drug delivery systems.