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Iowa State University

Chemistry

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Biophotonic Logic Devices Based On Quantum Dots And Temporally-Staggered Forster Energy Transfer Relays, Jonathan C. Claussen, W. Russ Algar, Niko Hildebrandt, Kimihiro Susumu, Mario G. Ancona, Igor L. Medintz Jan 2013

Biophotonic Logic Devices Based On Quantum Dots And Temporally-Staggered Forster Energy Transfer Relays, Jonathan C. Claussen, W. Russ Algar, Niko Hildebrandt, Kimihiro Susumu, Mario G. Ancona, Igor L. Medintz

Jonathan C. Claussen

Integrating photonic inputs/outputs into unimolecular logic devices can provide significantly increased functional complexity and the ability to expand the repertoire of available operations. Here, we build upon a system previously utilized for biosensing to assemble and prototype several increasingly sophisticated biophotonic logic devices that function based upon multistep Förster resonance energy transfer (FRET) relays. The core system combines a central semiconductor quantum dot (QD) nanoplatform with a long-lifetime Tb complex FRET donor and a near-IR organic fluorophore acceptor; the latter acts as two unique inputs for the QD-based device. The Tb complex allows for a form of temporal memory by …


Microbiosensors Based On Dna Modified Single-Walled Carbon Nanotube And Pt Black Nanocomposites, Jin Shi, Tae-Gon Cha, Jonathan C. Claussen, Alfred R. Diggs, Jong Hyun Choi, D. Marshall Porterfield Jan 2011

Microbiosensors Based On Dna Modified Single-Walled Carbon Nanotube And Pt Black Nanocomposites, Jin Shi, Tae-Gon Cha, Jonathan C. Claussen, Alfred R. Diggs, Jong Hyun Choi, D. Marshall Porterfield

Jonathan C. Claussen

Glucose and ATP biosensors have important applications in diagnostics and research. Biosensors based on conventional materials suffer from low sensitivity and low spatial resolution. Our previous work has shown that combining single-walled carbon nanotubes (SWCNTs) with Pt nanoparticles can significantly enhance the performance of electrochemical biosensors. The immobilization of SWCNTs on biosensors remains challenging due to the aqueous insolubility originating from van der Waals forces. In this study, we used single-stranded DNA (ssDNA) to modify SWCNTs to increase solubility in water. This allowed us to explore new schemes of combining ssDNA-SWCNT and Pt black in aqueous media systems. The result …


Cloning And Heterologous Expression Of The Spectinabilin Biosynthetic Gene Cluster From Streptomyces Spectabilis, Zengyi Shao Jan 2010

Cloning And Heterologous Expression Of The Spectinabilin Biosynthetic Gene Cluster From Streptomyces Spectabilis, Zengyi Shao

Zengyi Shao

Spectinabilin is a rare nitrophenyl-substituted polyketide metabolite. Here we report the cloning and heterologous expression of the spectinabilin gene cluster from Streptomyces spectabilis. Unexpectedly, this gene cluster is evolutionarily closer to the aureothin gene cluster than to the spectinabilin gene cluster from Streptomyces orinoci. Moreover, the two nearly identical spectinabilin gene clusters use a distinctly different regulation mechanism.