Begin by measuring the threshold time of the bio-ink using a rheometer with a temperature control element. Utilize a 365 nanometer light source to expose the testing platform of the rheometer and set the light intensity to a certain value. In the rheometer software, go to the time settings option and set the rheometer to acquire the time moduli data for 300 data points with each data point taken every 0.3 seconds.
Click the start test button on the rheometer software to begin the test. Simultaneously, click the start button of the light source. To calculate the threshold time, record the corresponding time counting from the start of exposure when the storage modulus data is equal to the loss modulus data.
Then build the absorbance test equipment by using upper and lower glass slides and the ring-shaped printed structure. Clamp the ring between the glass slides so that the inner circle of the ring forms the chamber. Place the chamber on the test area of the light intensity meter and set the light source to expose the chamber area.
When the test chamber is not filled with material from the absorbance test equipment, measure the incident light intensity, II, by reading the display of the light intensity meter. Next, fill the test chamber with 10 microliters of bio-ink. Expose the test chamber containing bio-ink to ultraviolet light at 365 nanometers.
Obtain the light intensity, IIH, by reading the display. When the value no longer changes on the light intensity meter, read the display to obtain the light intensity when the bio-ink is cured. The value is the solid absorbance, ISH.
