Research Summary - Matsui’s group is working in the fields of Nanotechnology and Biotechnology and the integration of these two areas (i.e., Bionanotechnology) is producing creative sciences with high technology impacts. Matsui’s research interests consist of; 1. Biomimetic Fabrication of Nano-Electronics, 2. Engineering New Peptide Nanowires from Nature, 3. Bio-Sensor Chips Engineered by Peptide Nanowires.

Non-lithographic fabrications of devices such as electronics and sensor have been studied extensively by assembling nanometer-sized building blocks into the device configurations. While various nanocomponents have been applied as building blocks to construct nanodevices, the more reproducible methods to assemble them onto precise positions are desirable. We have been fabricating peptide-based nanotubes (antibody) and functionalizing them with various recognition components (antigen), and our strategy is to use those functionalized peptide nanotubes, which can recognize and selectively bind a well-defined region on patterned substrates, as building blocks to assemble three-dimensional nanoscale architectures at uniquely defined positions and then decorate the nanotubes with various materials such as metals and quantum dots for electronics and sensor applications. Even though those antibody-incorporated nanomaterials can be immobilized at desired locations by the biomolecular recognition, their electric properties are necessary to be adjusted to function as building blocks for electric or sensor devices. Therefore, after configuring device geometries with these nanotubes by the biomolecular recognition, we turned on the biomineralization function of peptides on the nanotube sidewall to coat with various materials such as metals, semiconductors, and quantum dots for electronics, photonics, and sensor applications. The coating morphology such as particle-domain size and inter-particle distance on the nanotubes could be tuned by peptide sequences and conformations

Bioterrorism is becoming a major threat for many countries as a new style of war. To protect the public from such a biological attack, we need to establish improved diagnostic methods and sampling strategies in order to identify the pathogens more rapidly and precisely. Traditionally, pathogens have been detected by either targeting microorganisms with labeled recognition elements or probing their nucleic acids or antigens with various labeling agents via optical detection, electrochemical measurement, or mechanical transduction. However, label-free detection of microorganisms is more advantageous due to its simple procedure without any further incubation steps, thus reducing costs and enabling fast detection. Here we are developing two peptide nanotube-based methods to detect pathogens with scoring high on all of these sensing requirements. The first development is the antibody nanotube-based pathogen detection platform. In this platform, a pair of electrodes separated by a micrometric gap was bridged by antibody-coated peptide nanotubes, and the binding event between the virus and its antibody was detected by capacitance change between the electrodes. Due to the dielectric property of viruses, the binding of viruses with the antibody nanotubes decreased the permittivity of the surrounding medium, consequently decreasing the capacitance between the electrodes. The second approach is to apply peptide nanotubes incorporating recognition units with antibodies at their ends and fluorescent signaling units at their sidewalls as signal enhancer for flow cytometry. When viral pathogens were mixed with these antibody nanotubes in solution, the nanotubes rapidly aggregated around the viruses to form a networking structure and the size of the aggregates increased as the concentration of viruses increased. Trace quantities of viruses were detected on attomolar order by changes in fluorescence and light scattering intensities associated with aggregation of dye-loaded antibody nanotubes around viruses.

Selected publications

“Enzyme Urease as Nano-Reactor to Grow Crystalline ZnO Nanoshells at Room Temperature”, R. de la Rica and H. Matsui, Angew. Chem. Intl. Ed., 47, 5415 (2008).

“Comparison of Electrical Properties of Viruses Studied by AC Capacitance Scanning Probe Microscopy”, R.I. MacCuspie, N. Nuraje, S-Y. Lee, A. Runge, and H. Matsui, J. Am. Chem. Soc., 130, 887 (2008).

“Liquid/liquid interfacial epitaxial polymerization to grow single crystalline nanoneedles of various conducting polymers”, N. Nuraje, S. Kai, N.L. Yang and H. Matsui, ACS Nano, 2, 502 (2008).

“Virus Assay Using Antibody-Functionalized Peptide Nanotubes”, R.I. MacCuspie, I.A. Banerjee, S. Gummalla, H.S. Mostowski, P.R. Krause, and H. Matsui, Soft Matter, 4, 833 (2008).

"Crossbar Assembly of Antibody-Functionalized Peptide Nanotubes via Biomimetic Molecular Recognition”, L. Yang, N. Nuraje, H. Bai, H. Matsui, J. Pep. Sci., 14, 203 (2008).

“Fabrication of Au nanowire of uniform length and diameter using a new monodisperse and rigid biomolecular template, collagen-like triple helix”, H. Bai, K. Xu, Y. Xu, and H. Matsui, Angew. Chem. Intl. Ed., 46, 3319 (published on line as a hot paper) (2007).

“Biomimetic and Aggregation-Driven Crystallization Route for Room-Temperature Material Synthesis: Growth of beta-Ga2O3 Nanoparticles Using Peptide Assemblies as Nanoreactors”, S.Y. Lee, X. Gao, H. Matsui, J. Am. Chem. Soc., 129, 2954 (2007).