The immune system is an important aspect of human health and relates to a number of diseases that are still not fully understood. The majority of signaling from immune cells comes from proteins, but the signal is difficult to measure since it is not able to be amplified. Microfluidic volume reduction, which increases the concentration of proteins in solution, is one solution for solving this issue. Multiplexed protein analysis on immune cells has the potential to reveal new insight into correlations and unknown signaling relationships. In addition to this, it is important to study immune cells that are grown in in vitro environments that accurately replicate the in vivo conditions. Building 3D tissue constructs with human cells could greatly improve the field of drug discovery a...[ Read more ]

The immune system is an important aspect of human health and relates to a number of diseases that are still not fully understood. The majority of signaling from immune cells comes from proteins, but the signal is difficult to measure since it is not able to be amplified. Microfluidic volume reduction, which increases the concentration of proteins in solution, is one solution for solving this issue. Multiplexed protein analysis on immune cells has the potential to reveal new insight into correlations and unknown signaling relationships. In addition to this, it is important to study immune cells that are grown in in vitro environments that accurately replicate the in vivo conditions. Building 3D tissue constructs with human cells could greatly improve the field of drug discovery and make the process safer.

In the first section, we demonstrate a low-cost open source bioprinting platform for 3D printing tissue scaffolds. New hardware was developed, including a bioprinter controller, heated syringes, a cooled bed and a digital pressure regular for precisely controlling the extrusion force. Software was also written to allow automated slicing of models, which makes the process of generating bioprint compatible g-code much simpler. We tested the cell viability of cell encapsulated hydrogel material and 90% cell viability was achieved. We hope that these tools will reduce the barriers of entry and enable wider adoption of bioprinting.

In the next sections, we developed a bead-based hydrodynamic sorter for accurately addressing bead to assay chambers. A custom bead sorting software allowed communication between the camera, microscope and microfluidic valve, which allowed automated sorting of beads to assay chambers with a speed of 5.7 beads per minute and 96% accuracy. The beads were then used for performing multiplexed protein measurement on lysed T cells stimulated for 12 hours. Eleven proteins were measured simultaneously for each cell and compared to internal protein standards to calculate the number molecules released by the cell. Software tools were created to automate image processing as well as build tools for interactively assessing data quality and perform single-cell analysis. The T cell protein showed high production of IL-2 which was expected for Jurkat cells with PMA/ionomycin stimulation. Other proinflammatory proteins such as CCL3/MIP-1a, TNF-a, IL-12p70 and IFN-y were also highly expressed. This suggested that the immune cell was matured towards the Th1 path.