Vibrational Analysis of Biopolymer-Based Hydrogels Using 3D-Printed Test Structures for Applications in Bioprinting

The mechanical properties of hydrogels suitable for applications in the field of bioprinting, which tries to develop three-dimensional tissue equivalents, are crucial for the proper fulfilment of their functions in the human body. This aspect is especially important regarding types of tissues which have to withstand applied mechanical forces. Due to their high water content similar to the human body and their tunable mechanical properties, hydrogels based on biopolymers are ideally suited for such applications. In this work, the first results of a novel method for the indirect measurement of the mechanical properties of hydrogels using laser-Doppler vibrometry and 3D-printed test structures are presented. Thanks to the experimental design hydrogels can be cast directly over such beam-like test structures without any leakage. First results show that the resonance frequencies of the beam structure are modulated by the material properties of the different hydrogels placed on it, enabling future applications and further experiments. For comparing the measurement data with the mechanical properties of the samples used, indentation-based measurements have been carried out. This approach can be integrated into existing bioprinting workflows and enables the non-destructive monitoring of biopolymer-based hydrogels in their mechanical properties.