Acoustic and mechanical characterization of gelatin methacryloyl scaffolds for tissue engineering applications

Gelatin methacryloyl (GelMA) is a highly biocompatible, biodegradable material and a 3-D printable option for constructing tissue engineering scaffolds. Improved material characterization of GelMA is necessary to optimize preparation techniques, evaluate tissue similarities, and validate tissue engineering potential. Conventional testing methods are through destructive, one-time measurements, yet nondestructive tests are desired for evaluating long-term changes. In the present study, ultrasound techniques were utilized to measure mechanical properties of GelMA tissue scaffolds. Varying concentrations of GelMA and ultraviolet light curing time produced scaffolds with a range of material properties. Ultrasound pulse-echo techniques were used for a non-destructive acoustic characterization procedure, and parameters including speed of sound, acoustic impedance, and attenuation coefficient were measured. To further evaluate the material properties of the scaffolds, compression testing was performed. Physical parameters of GelMA were found to be similar to those of native tissues, demonstrating that GelMA scaffolds are biomimetic. The impact of GelMA concentration and curing time will be discussed to inform the selection of preparation parameters for specific tissues. Acoustic characterization proves to be a promising technique for evaluating the structure and function of the scaffolds and could serve as an indicator of tissue scaffold health while providing real-time monitoring in vivo.