UC Santa Cruz

Stem cell biology has enabled the development of 3D organ-specific in vitro models that mimic aspects of in vivo tissue. The analysis of tissue cultures, particularly brain organoids, takes a high degree of coordination, measurement, and monitoring. Here, I have developed a novel microfluidic platform that automates the culture of individual organoids in isolated microenvironments at user-defined flow rates. This technology has enabled greater homeostatic regulation of culture's media through frequent, low-volume replenishment cycles. RNA sequencing (RNA-seq) analysis of automated cerebral cortex organoid cultures showed benefits in reducing glycolytic and endoplasmic reticulum stress compared to conventional in vitro cell cultures. For the first time, longitudinal metabolic profiles tracing glucose and lactate over 105 days of culture were achieved for six cerebral cortex organoid protocols.

The microfluidic technology was advanced to integrate electrophysiology and imaging into a unified system for feedback-driven studies. An Internet of Things (IoT) architecture was developed to enable continuous, communicative interactions among sensing and actuation devices, achieving precisely timed control of biological experiments. Computer vision for fluid volume estimations of aspirated media was used as feedback to rectify deviations in microfluidic perfusion during media feeding/aspiration cycles. The system performed 7-day studies of mouse cerebral cortex organoids, comparing manual and automated protocols. The automated experimental samples maintained robust neural activity throughout the experiments; however, the system enabled hourly electrophysiology recordings that revealed dramatic temporal changes in neuron firing rates not observed in once-a-day recordings.