2. Spring Celebration Donald Lucas, Ph.D. D_lucas@lbl.gov Profs. Cathy Koshland (PI), Lydia Sohn, Peidong Yang, and John Arnold Nanotechnology-Based Environmental Sensing

3. Nanomaterials exhibit different and sometimes unique properties when compared to gas phase or bulk materials Can we exploit these properties to detect and quantify species such as heavy metals and biomolecules used in remediation? Why Nanotechnology?

4. Nanoparticles are Everywhere! PbSe NaCl before and after laser irradiation PbSe Nano-onions Cover Photo: C&E News May 1, 2006 Au and Ag nanoparticles and nanorods

5. Specific Aims Develop low-cost sensors and sensor arrays for measuring chemical species such as arsenic and mercury using existing nanoparticle properties that can be probed optically and electronically.

6. Specific Aims Develop low-cost sensors and sensor arrays for measuring chemical species such as arsenic and mercury using existing nanoparticle properties that can be probed optically and electronically. Investigate the use of new manufactured nanostructured materials for molecular detection, including structures such as coated nanoparticles and sensor arrays.

7. Specific Aims Develop low-cost sensors and sensor arrays for measuring chemical species such as arsenic and mercury using existing nanoparticle properties that can be probed optically and electronically. Investigate the use of new manufactured nanostructured materials for molecular detection, including structures such as coated nanoparticles and sensor arrays. Develop methods to identify biomolecules (specific antibodies/antigens used in bioremediation) by probing their unique local electronic properties

8. 5 nm colloidal gold solution Temperature controlled Hg bead 3 x 4.0 mL UV-Vis silica cuvettes in series Hg (0) N2N2 UV-Vis spectrum (nm) A Surface Plasmon Resonance Hg(0) Detection

9. Gold Morphology Changes with Hg TEM images of the colloidal gold solution before and after mercury exposure. The gold does not agglomerate and the concentration of individual particles in solution increases with Hg exposure. K. Scallan et al. 9 th Int. Congress on Toxic Combustion Byproducts (2005).

10. Arsenic Detection: Shape-dependent Plasmon Resonances F. Kim et al. Angew. Chem. Int. Ed. 2004,43, 3673.

11. Surface Enhanced Raman Spectroscopy: Ag Nanocrystal Enhancement Factor = 2 x 10 9 ! A. Tao et al. Nano. Lett. 3, 1229, 2003. J. Phys. Chem. B 109, 15687, 2005. Nature, 425, 243, 2003.

12. On-Chip Artificial Pore Saleh & Sohn, Rev. Sci. Inst. (2001) & PNAS (2003) Uses resistive pulse sensing to detect: 1. nm-sized colloids 2. single cells 3. single molecules

13. Applications A Novel Immunoassay Detects size change No labeling involved Particle Sizing Pore length = 1um diam x 10 um long Device resolution corresponds to 2-4% variation of colloids