Direct visualization of interactions between drug-loaded nanoparticles and the cancer cell nucleus is crucial for understanding the mechanism behind cancer cell death. Nanoconstructs composed of nucleolin-specific aptamers and gold nanostars were actively transported to the nucleus and were found to induce major changes in nuclear phenotype: near the site of the nanoconstruct, nuclear envelope invaginations occurred. We have shown that the number of local deformations could be increased by ultra-fast, light-triggered release of the aptamers from the surface of the gold nanostars. Cancer cells with more nuclear envelope folding showed increased apoptosis as well as decreased cell viability. This newly revealed correlation between drug-induced changes in nuclear phenotype and increased therapeutic efficacy could provide new insight for localized cancer therapy.
March 2012: Duncan, Jung Heon, and Patrick's work is featured on Nanowerk
Nov 2011: Angela, Alex and Cliff are selected as Hierarchical Materials Cluster Program Fellows.
Nov 2011: Kayla is selected as a Biotechnology Cluster Program Fellow.
Nov 2011: David Thomas nominated for Meteor Award for Excellence in a New Position.
Sept 2011: Mark's paper on portable, benchtop photolithography is published in Small.
July 2011: Christina's paper on the optical properties of tipless nanopyramids is published in Small.
July 2011: Christina and Colleen's paper on the Three-Channel Spectrometer was published in JPCC.
June 2011: Mark and team win top prize in the Dow Sustainability Innovation Challenge.
May 2011: Wei's paper on dark lattice plasmons is AOP in Nature Nanotech.
April 2011: Kelsey and Julia's perspective on 3D SERS NP substrates is AA in Chem. Sci.
April 2011: Matt and Christina's paper on chemistry in microfluid channels is on the cover of J. of Chem. Educ.
Feb 2011: Sane Lithography highlighted on cover of Nano Lett.
Solid-state photolithography (SSP) enables the capabilities of one of the most important tools in nano- and microfabrication, the mask aligner, to be performed on the benchtop. SSP can create patterns over a wide range of different length scales (down to several hundred nanometers) and over macroscale areas at a fraction of the cost of current instruments. The design of the SSP system alleviates the need for dedicated power supplies, vacuum lines, and cooling systems, and thus makes SSP a compact and portable photolithography option. The cover image is a close-up of the ultraviolet light-emitting diode (LED) array that is used as the solid-state light source for SSP.
Featured Research: The Dark Side of Surface Plasmons
Plasmonic nanostructures concentrate optical fields into nanoscale volumes, which is useful for plasmonic nanolasers, surface enhanced Raman spectroscopy, and white-light generation. However, the short lifetimes of the emissive plasmons correspond to a rapid depletion of the plasmon energy, preventing further enhancement of local optical fields. Dark (subradiant) plasmons have longer lifetimes, but their resonant wavelengths cannot be tuned over a broad wavelength range without changing the overall geometry of the nanostructures. We have discovered a new type of subradiant plasmon with a narrow (~5 nm) resonant linewidth that can be easily tuned by changing the height of large (> 100 nm) gold nanoparticles arranged in a two-dimensional array. At resonance, strong coupling between out-of-plane nanoparticle dipolar moments suppresses radiative decay, trapping light in the plane of the array and strongly localizing optical fields on each nanoparticle. This new mechanism can open applications for subradiant plasmons because height-controlled nanoparticle arrays can be manufactured over wafer-scale areas on a variety of substrates.
Oct 2010: Broadband plasmonic microlenses are featured in Nanotechweb.org.
Oct 2010: Hanwei's paper on plasmonic microlenses is published in Nano Lett.
Sept 2010: SANE lithography is featured in physicsworld.org
Sept 2010: Duncan is selected as a Hierarchical Materials Cluster Program Fellow.
Two images of ours were selected for the FY2011 Budget Supplement: (1) A dark field optical image of cancer cells decorated with gold nanopyramids via antibodies on the pyramid surface (foreground); and (2) an SEM image of arrays of nanofabricated gold pyramids siutated on silicon pedestals (background). More information can be found at nano.gov.
Aug 2010: Min Hyung and Mark's paper on programmable soft lithography (SANE and inSANE) is ASAP in Nano Lett.
Aug 2010: Jiun-Chan's 3D nanohole paper is highlighted in Nanotechweb.org
Jul 2010: Jiun-Chan's 3D nanohole paper is published in Nano Lett.
Jul 2010: Mark wins a Ryan Fellowship from Northwestern
May 2010: Hanwei and Jiun-Chan's biosensing paper is highlighted in Nanotechweb.org
May 2010: Hanwei and Jiun-Chan's paper on biosensing with molded plasmonic crystals is published in Nano Lett.
Apr 2010: Video highlights Odom's use of Lecture Capture in teaching freshman
Apr 2010: Mark wins an NDSEG Fellowship
Apr 2010: Kelsey wins NSF and DOE Fellowships
Mar 2010: Min Hyung's paper on nanostencil printing is accepted in Angew. Chemie.
Mar 2010: Odom's testing of new technology for teaching freshmen is highlighted in NUIT's newsletter
Mar 2010: Kelsey & Warefta's paper on assembled nanopyramids & SERS is published in J. Phys. Chem. Lett.
Feb 2010: Phoebe's paper on TaS2 nanotubes is accepted in Small
Feb 2010: Our NNI Cover is in NU's Feature Box
Feb 2010: Wei's paper on rhombic plasmonic crystals is featured on NanotechWeb.org
Feb 2010: Min Hyung's paper on nanostencil printing is accepted in Angew. Chemie
Jan 2010: Kelsey wins a Churchill Scholarship
Jan 2010: Wei's paper on rhombic plasmonic crystals is ASAP in ACS Nano
Jan 2010: Julia's paper on nested pyramidal particles is ASAP in J. Phys. Chem. C
Dec 2009: Hanwei's Feature Article on plasmonic crystals is published in Adv. Func. Mater.
Dec 2009: Our paper on hierarchical plasmonic lattices is featured in Chem. Phys. Lett. on the cover
Nov 2009: Wei receives a MRSEC Fellowship Award
Oct 2009: Odom is featured as one of Research Corporation's Cottrell Scholars
Sept 2009: Steven is selected as a HMCP Fellow
We are investigating the optical properties of 3D anisotropic plasmonic particles. Recently, we have designed a way to create nested Au pyramidal nanoshells. These particles exhibit two plasmon resonances at visible and near-infrared wavelengths that can be manipulated depending on the size of the gap between inner and outer pyramidal shells. We found that larger gaps (30 nm) exhibited much larger Raman scattering responses compared to smaller gaps (5 nm) in the nested pyramidal shells. The SERS-activity of these anisotropic particles can be optimized by adjusting the distances between the inner and outer Au shells.
Sept 2009: Julia receives an NSEC Fellowship Award
Sept 2009: Wei is selected as a Northwestern Ryan Fellow
Aug 2009: Eunah and Rich's paper on controlling the size of arsenic trioxide nanoparticles is published in JACS
Jun 2009: Jeremy and Chris' paper on tantalum oxide nanotubes is published in J. Mater. Chem.
Surface plasmon polaritons (SPPs) are responsible for exotic optical phenomena including negative refraction, surface enhanced Raman scattering, and nanoscale focusing of light. Although many materials support SPPs, the choice of metal for most applications has been based on traditional plasmonic materials (Ag, Au) because there have been no side-by-side comparisons of the different materials on well-defined, nanostructured surfaces. Using a platform based on large-area arrays of nanopyramids, we have provided the first comparison of traditional and relatively unexplored plasmonic materials. These results generated three surprises: (1) the narrowest surface plasmon resonances to date (which also correlate with the highest observed refractive index sensitivities); (2) surface plasmon coupling efficiencies of weak plasmonic materials (Cu and Al) that exceed those of strong plasmonic materials (Ag and Au) under certain conditions; and (3) nanopatterned Pd substrates that were more sensitive than Ag ones for detecting biomolecules.
Jun 2009: Min Hyung's paper on quasi-1D slit arrays is published in Nano Letters and highlighted by NanotechWeb.org
May 2009: Odom is selected to join the 2010-2011 Defense Science Study Group (DSSG)
Apr 2009: Christina's paper on anisotropic core-shell particles is published in JPCA
Mar 2009: Liza's paper on optical corrals is published in ACS Nano and highlighted in a Perspective in ACS Nano
Mar 2009: Warefta's paper on photothermal response and nanoparticle shape is published in Nano Lett and highlighted by NanotechWeb.org
Feb 2009: Odom is awarded the MRS 2009 Outstanding Young Investigator Award
Feb 2009: Hanwei's paper on the RA-SPP effect in Pd nanohole arrays is published in Opt Express
Jan 2009: Odom is featured in C&E News for the ACS Fresenius Award
Jan 2009: Jeunghoon and Warefta's paper on refractive index sensitivity of Au pyramids is published in JPCC
Dec 2008: Hanwei's paper on screening new plasmonic materials using nanopyramidal gratings is published in PNAS
We are working on a new class of asymmetric metal particles: nanofabricated pyramids. Because their nanofabrication procedure is extremely versatile, pyramids are ideal for designing multifunctional plasmonic materials that have high potential for creating unexpected applications. For example, pyramids can be generated with variable sizes, thicknesses, and multi-metal compositions. They can also be designed with blunt, ultra-sharp, or no tips, and site-specific chemical and biological functionality on different portions of the pyramids can be achieved. The optical properties of gold pyramids can be tuned across visible and near-infrared wavelengths by changing a variety of parameters. Large (> 250 nm) pyramids support multipolar surface plasmon resonances, which can be used for imaging and spectral identification of their orientation in condensed media.
Dec 2008: The Special Issue in Nanoscience & Guest Editorial for Acc Chem Res is published
Nov 2008: Our benchtop nanopatterning workshop in Africa is highlighted in Adv. Mater.
Oct 2008: Our paper on nanofabricating plasmonic structures is In Advance in Ann Rev of Phys Chem
Sep 2008: Prof. Odom receives a 2008 NIH Director's Pioneer Award
Sep 2008: Our paper on multifunctional pyramids is published Acc Chem Res
Aug 2008: Prof. Odom is awarded the 2008 National Fresnius Award
Aug 2008: Chris' article on transition metal chalcogenide nanomaterials is published in J. of Solid State Chemistry
Apr 2008: Our invited Perspective on gold nanoparticles is published in ACS Nano
Feb 2008: Liying's paper on protein crystallizaton in microwells is published in JACS
Dec 2007: Jeunghoon's paper on bi-materials pyramids is published in Adv. Mater.
Nov 2007: Min Hyung's paper on microscale arrays of nanoholes is published in Small
Oct 2007: Warefta's paper on selectively functionalizing gold pyramids is published in JPCC.
The interaction of light with surface plasmons — collective oscillations of free electrons — in metallic nanostructures leads to novel optical phenomena. These structures typically consist of ordered arrays of particles or holes with sizes of the order of 100 nm. However, surface plasmons can interact with each other over much longer distances, so the ability to organize nanoscale particles or holes over multiple length scales could lead to new plasmonic metamaterials. We have developed a new nanofabrication technique — soft interference lithography — to produce such metamaterials. These structures include various infinite and finite-area arrays of nanoholes and nanoparticles as well as patterns that contain both metallic and dielectric materials. The free-standing gold film of nanoholes shown on the cover demonstrates the hierachical patterning capabilities of soft interference lithography.
Oct 2007: Our paper on benchtop nanoscale patterning using soft lithography is published in J. Chem. Ed.
Sept 2007: Joel's paper on plasmonic metamaterials is feature on the cover of Nature Nanotech.
May 2007: Chris' paper on chemical nanofabrication is published in J. Mater. Chem.
Apr 2007: Joel's Au pyramids on Si pedestals receives 1st place at the 2007 Spring MRS Science as Art competition.
Mar 2007: Prof. Odom is awarded the Rohm and Haas New Faculty Award
Mar 2007: Scott's paper on large-area, addressable nanoscale OLEDs is published in Small
We have combined bottom-up chemical methods and top-down nanoscale patterning techniques—chemical nanofabrication—to generate patterned and free-standing transition metal chalcogenide (TMC) nanostructures. This approach is general and flexible and can produce (1) arrays of MnXy (M = Ni, Ag; X = S, Se) nanoscale structures with different shapes and sizes; (2) crossed arrays of nanostructures out of different TMC materials using a two-stage conversion process; and (3) free-standing nanostructures of NiS2 materials. We can control independently the width, height and aspect ratio of the TMC structures as well as the pitch and area (> 1 square inch) over which they are patterned.
Aug 2006: Hanwei's paper on surface-plasmon mediated enhancement in metallic nanohole arrays is published in Nano Letters
Jul 2006: Joel's paper on the optical properties of pyramid arrays is published in JPCB
By combining near-field and far-field spectroscopy, we have provided direct evidence for the role of surface plasmons (SPs) in the enhanced optical transmission of light through metallic nanoscale hole arrays. Near-field optical images directly confirmed the presence of surface plasmons on gold nanohole arrays with interhole spacings larger than the surface plasmon wavelength. Either lambda (SP) or lambda (SP)/2 was observed depending upon the thickness of the film. Far-field spectroscopy revealed a surface plasmon band that contributed a factor over eight times to the transmission enhancement.
Apr 2006: Our paper on large-area nanopatterning is published in Accounts of Chemical Research
Mar 2006: Joel is selected as a US-participant in the Nobel Laureates Meeting in Lindau
Two-dimensional arrays of gold pyramidal nanoparticles have been aligned, encapsulated, and manipulated within a large (> 1 cm x 1 cm) transparent elastomeric film. The orientation-dependent optical properties of these arrays exhibited localized plasmon resonance modes that were found to be sensitive to both the propagation wavevector and polarization vector.
Feb 2006: Laura receives a Gates Cambridge Fellowship
Feb 2006: Eric's paper on tetrahedral SnS crystals is published in Small
Dec 2005: Chris' paper on patterned MoS2 nanostructures is published in Adv. Mater.
Nov 2005: Prof. Odom is interviewed on NPR's Earth & Sky radio show.
We have developed a flexible and parallel procedure to generate large-area, free-standing films of subwavelength hole arrays. This method is materials-general, and multi-layered films of different materials were constructed. The optical quality of these films was tested using a near-field scanning optical microscope, which revealed the formation of surface plasmon standing wave patterns that were consistent with numerical simulations.
Oct 2005: Soo's paper on surface plasmon standing waves on nanohole arrays is published in Nano Letters
Sept 2005: Laura Hughes receives the Sarrett Award in chemistry at Northwestern.
July 2005: Our work with the Lauhon group is featured on the cover of APL 25 Jul issue
May 2005: Joel's paper on mesoscale pyramids is published in N ano Letters
May 2005: Prof. Odom is selected as a 2005 Cottrell Scholar from Research Corporation.
We have developed a simple procedure that can generate free-standing, mesoscale metallic pyramids composed of one or more materials and having nanoscale tips (radii of curvature less than 2 nm). These pyramids can be composed of two or three different layers with control over their materials and chemical functionality.
May 2005: Scott Price and Numrin Thaitrong receive Undergraduate Summer Research Grants
April 2005: Prof. Odom is awarded a DuPont Young Investigator Grant
April 2005: Laura Hughes receives a Goldwater Fellowship
February 2005: Prof. Odom receives a 2005 Sloan Research Fellowship
We have developed a new synthetic approach to one- (1D) and two-dimensional (2D) NbSe2 nanoscale materials using soft chemical methods. Our one-pot synthesis provides a direct route to control the morphology of nanostructures that can exhibit complex electronic properties, and can produce layered, nanocrystalline materials in high yield.
January 2005: Sekar's paper on NbSe2 nanocrystals is published in JACS
November 2004: Hanwei Gao, Warefta Hasan, and Min Hyung Lee join the group
October 2004: Prof. Odom is named to MIT Technology Review TR100 as "one of the world's top young innovators"
August 2004: Liza's paper on templated assembly of CdSe nanocrystals is published in Adv. Materials
August 2004: Eric's paper on directed assembly of thin ZnO nanowires is published in Adv. Materials
Nanoscale fabrication methods provide a unique approach to synthesize nanoscale materials. We have used laser-assisted embossing to generate close-packed arrays of hemispherical nanowells with zeptoliter (zL)-volumes. Nanowells with diameters as small as 50 nm were used as reaction vessels for the preparation of individual inorganic salts and semiconducting nanocrystals in individual nanowells.
July 2004: Jeremy's work on nanocrystals in nanowells is highlighted in Nanopicture of the Day
July 2004: Jeremy's work on nanocrystals in nanowells is highlighted in "nanozone" in Nature Materials
June 2004: Jeremy's paper on nanowells (zeptoliter beakers) is published in Nano Letters
May 2004: Eric, Jeremy, and Liza pass their qualifying exams
May 2004: Postdoc Soo Kwak joins the lab
January 2004: Prof. Odom receives an NSF CAREER Award
October 2003: Prof. Odom receives a David and Lucile Packard Fellowship