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

• 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?

Nanoparticles are Everywhere!

PbSe

NaCl before and afterlaser irradiation

PbSe

Nano-onions

Cover Photo: C&E NewsMay 1, 2006

Au and Ag nanoparticlesand nanorods

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.

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.

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

0.00.10.20.30.40.50.60.70.80.91.0

400 500 600 700

• 5 nm colloidal gold solution

• Temperature controlled Hg bead

• 3 x 4.0 mL UV-Vis silica cuvettes in series

Hg (0)

N2

UV-Vis spectrum

(nm)

A

Surface PlasmonResonance

Hg(0) Detection

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. 9th Int. Congress on Toxic Combustion Byproducts (2005).

Arsenic Detection: Shape-dependent Arsenic Detection: Shape-dependent Plasmon ResonancesPlasmon Resonances

F. Kim et al. Angew. Chem. Int. Ed. 2004,43, 3673.

Surface Enhanced Raman Spectroscopy: Ag Nanocrystal

Enhancement Factor = 2 x 109!

A. Tao et al. Nano. Lett. 3, 1229, 2003.J. Phys. Chem. B 109, 15687, 2005.

Nature, 425, 243, 2003.

On-Chip Artificial PoreSaleh & Sohn, Rev. Sci. Inst. (2001) & PNAS (2003)

Uses resistive pulse sensing to detect:1. nm-sized colloids2. single cells3. single molecules

ApplicationsA 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