Short Range systems rely on cell-cell contact and allow for fine-tuned control of expression in space. We discovered that higher transfection levels of the receiver circuit in these systems leads to larger fold change expression. Therefore we hypothesis that the leaky level of expression in these systems is dependent on the concentration of repressor expressed on their surface.

 

Medium Range systems were designed using two strategies. 1) VLPs which allow for delivery of proteins of interest between cells. Production of these particles can be tuned via small molecule induction. As many different proteins of interest can be transferred, generation of patterns in space dependent on more than one molecular cue is a goal for these systems. 2) Exosomes thought to generate little to no immune response for delivery of protein or mRNA is another alternative system being pursued.

 

Long Range systems were design based on the apple flavonoid Phloretin. These system have the ability to produce their own small molecule given a Phloretic acid precursor. The independent production of phloretin being orthogonal to native mammalian systems and small molecule nature should allow for more complex and gradient based interfacing with organoid systems. Quantification of this system is underway.