Michel M. Maharbiz (Advisor)

We develop a technique for producing synthetic microbial patterns by means of direct activation and inactivation of gene expression in an initially homogenous population of cells using a microfluidic chemical interface system. A strain of E. coli was engineered such that the presence of the membrane diffusible molecule acyl-homoserine lactone (AHL) activates the production of more AHL, thereby creating a positive feedback loop. Since the half-life of AHL decreases in high pH solutions, this feedback loop can be inhibited in a specific area by modulating the local pH using a...

We have successfully adapted a consumer-grade inkjet printer for use as a means of controlling spatio-temporal gene expression in 2D cell culture. Specifically, we take advantage of a high-resolution printer designed to print on the surface of CDs. By modifying CD surfaces to contain customized Petri dish wells, we are able to culture E. coli in the wells and print various morphogens onto the surface of the culture. By varying the geometry of printed patterns of lactose and glucose we have demonstrated spatiotemporal control over the genetic activity of the lac operon. Having...

Nearly all medical implants and tissue engineered structures (i.e. lab-grown organs) are implanted or grown in a manner where it is difficult to non-destructively assess performance or progress and to make adjustments on the fly. For instance, suppose we wish to engineer a vascular graft to repair a damaged coronary blood vessel. In this case, we would start by taking a scaffold material shaped like a blood vessel and then coating it with endothelial and smooth muscle cells. We would then 'grow' the structure in a bioreactor for a fixed period of time and then implant it into the...