This article presents the design and development of a new hands-free ultrasonication robot for filamentous fungi homogenization. The platform was constructed with a modified inexpensive 3D printer, equipped with an upward-facing camera, a custom-designed wash station, and an add-on sonicator. While machine vision accomplished sample well screening based on image subtraction and color thresholding, it also determined the level of fungi homogeneity using color variance. Model fitting reveals that the process of filamentous fungi homogenization using ultrasonication included a period of significant exponential decay. Therefore, this procedure allowed for the rapid homogenization of the fungal samples during the initial stages of ultrasonication treatment followed by a deceleration in homogenization. Furthermore, a factorial experiment showed that higher sonicator power and temperature accelerated the homogenization process, while the cultivation time exhibited no effect on homogenization. In addition, the model parameters were varied between the wells, even when subjected to the same settings, meaning that the system cannot use the same asymptote of the homogeneity level to establish the termination time for different wells. Therefore, we used the standard deviation of the four most recent homogeneity level values to determine the termination time. This method was used for feedback control, forming a fully automated robot that did not require manual intervention during the experiment. A validation test on filamentous fungi demonstrated that the system was able to provide target quality of samples efficiently.
Keywords: fungi homogenization measurement; fungi homogenization modeling; laboratory automation; robotics; ultrasonication.