Gruner Group Research

Lab Research Summary [.pdf 462 kb]

Pixel Array Detector (PAD): [PAD homepage] The PAD group focuses on the development of CMOS based x-ray detectors for x-ray science experiments. Since CMOS is a highly developed integrated circuit platform that has benefitted from prolonged development in private industry, it offers finely tuned, ever-advancing, technology that can be exploited for the construction of cutting-edge x-ray sensors. The advancement of science using x-ray scattering and radiogrpahy is fundamentally dependent on the capabilities of the detectors used and it is therefore difficult to over estimate the importance of pixel array detectors.

Examples of projects in the PAD group include a detector for ultrafast microsecond x-ray imaging; large dynamic range detectors for macromolecular protein crystallography developed in partnership with industry; and a project to develop a detector for single molecule scattering experiments to be performed with X-ray Free Electron Laser (XFEL) at the Linac Coherent Light Source (LCLS).

[1] The next great leap in X-ray Science (Alper Ercan, Matt Renzi, Mark W. Tate)
[.pdf 410Kb / Cornell Press Release, 26th Feb 2002 / Cornell Chronicle Article, 7th March 2002]

Proteins under Pressure: Proteins are nature’s own molecular machines that perform a dizzying array of tasks within every living cell. Their operation is determined by intra and inter-molecular forces that are not yet well understood. Pressure modifies those basic molecular interactions and has a marked effect on organisms and their proteins. Lysozyme unfolds at high pressure just as it would if heated; eggs cook at high pressure with no heat. Yellow Fluorescent Protein changes its fluorescence spectrum when pressurized. High pressure cooling of protein crystals causes them to diffract better than they would if flash frozen.
We use a host of techniques including Small Angle X-ray Scattering (SAXS), protein crystallography at Cornell’s own MacCHESS facility and computational quantum chemistry to study the effects of pressure on proteins. These experiments probe how pressure deforms the structures of proteins and how it affects the molecular interactions inside proteins and between them. These results also contribute to the molecular description of the role of pressure in biology.
[1] Marcus D. Collins et al., Cooperative water filling of a nonpolar protein cavity observed by high-pressure crystallography and simulation, PNAS 2005 102: 16668-16671. [.pdf 320 Kb]
[2]Chae Un Kim, Raphael Kapfer and Sol M. Gruner, High-pressure cooling of protein crystals without cryoprotectants, Acta Cryst. (2005). D61, 881-890 [.pdf 863 Kb]
[3] Proteins Under Pressure - Buz Barstow [.pdf 4.92 Mb]

Nanocomposite Self-Assembling Materials: Polymers and inorganics (silica, ceramics, etc.) can be combined to make exciting new hybrid materials. They can be designed to form complex structures on the molecular, nanometer, mesoscale and bulk lengthscales and have numerous potential applications ranging from catalysis to photonic crystals. We make these nanocomposite structures using block copolymers and study their properties with X-ray scattering and electron microscopy. [ Tell me more about these exciting polymers]

[1] B.-K. Cho, et. al., Mesophase Structure-Mechanical and Ionic Transport Correlations in Extended Amphiphilic Dendrons, SCIENCE 305, 2004, 1598-1601, 1527[.pdf 191 Kb]
[2]A Jain, et. al., Direct Access to Bicontinuous Skeletal Inorganic Plumber's Nightmare Networks from Block Copolymers, Angew. Chem. Int. Ed. 44, 2005, 1226–1229 305.[.pdf 230 Kb]
[3]P Du, et. al. Additive-Driven Phase-Selective Chemistry in Block Copolymer Thin Films; The Convergence of Top-Down and Bottom-Up Approaches. Advanced Materials, 16, 2004, 953-957. [.pdf 501 kb]

Cornell High Energy Synchrotron Source: Professor Sol Gruner is heavily involved with the Cornell High Energy Synchrotron Source (CHESS), a world class X-ray facility located on campus in Ithaca. Group members regularly perform experiments at CHESS and projects are available in Instrumentation, Materials Science, X-ray Physics and Accelerator Physics. In addition, plans are afoot for the Energy Recovery Linac, a revolutionary new type of X-ray light source.
[1] CHESS link: CHESS