1. The UC Berkeley & UCSF Graduate Program in Bioengineering, Berkeley, CA 94720, USA, 2Department of Bioengineering, University of California, Berkeley, CA 94720, USA, 3Energy Biosciences Institute, Berkeley, CA 94720, USA, 4Department of Industrial Engineering and Operations Research, University of California, Berkeley, CA 94720, USA and 5Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA 94720, USA