Directed growth of uromyces hyphae on integrated circuit substrates

We report on the initial findings of a program involving the directed growth of fungal hyphae on custom-designed integrated test circuits for the purpose of creating a biohybrid integrated system. The biological element in this work is Uromyces appendiculatus, an organism which has been shown to exhibit precise and unique topographical signal recognition. The integrated circuit is fabricated using standard semiconductor processing techniques, with guiding elements etched into the final layer of metallization. The spores germinate on contact pads in the circuit and this results in the formation of germ tubes which are guided by the vectoring elements toward other contacts. We show that the vectoring structures are capable of steering the hyphae to intended connection/ termination points through a wide range of angles. In addition, we demonstrate that self-assembled monolayers of n -octadecyltrichlorosilane on the circuit materials result in superior germination characteristics compared to untreated surfaces. We also speculate on the potential applications of such cell-circuit hybrids.