A5086006178- Gold and Silver Nanoparticles Synthesis and Applications
- Iron oxide chemistry and applications
- Plant nutrient uptake and metabolism
- Bacterial Genetics and Biotechnology
- Minerals Flotation and Separation Techniques
- Nanocluster Synthesis and Applications
- Pancreatic function and diabetes
- Protein Structure and Dynamics
- Amino Acid Enzymes and Metabolism
- nanoparticles nucleation surface interactions
- Nanoparticles: synthesis and applications
- Advanced Electron Microscopy Techniques and Applications
- Calcium Carbonate Crystallization and Inhibition
- Nanomaterials for catalytic reactions
- Electron and X-Ray Spectroscopy Techniques
- Coagulation and Flocculation Studies
- Advanced Nanomaterials in Catalysis
- Advanced Materials Characterization Techniques
- Enzyme Structure and Function
- Biosensors and Analytical Detection
- Economic and Technological Developments in Russia
- Electrochemical Analysis and Applications
- Cellular transport and secretion
- Genetics and Neurodevelopmental Disorders
- Microbial Community Ecology and Physiology
Stanford Synchrotron Radiation Lightsource
2023-2024
SLAC National Accelerator Laboratory
2023-2024
University of Illinois Urbana-Champaign
2013-2018
Urbana University
2014-2016
University of Minnesota
2010-2013
Technion – Israel Institute of Technology
2013
Mount Holyoke College
2010
Anisotropic (nonspherical) metal nanoparticles are of widespread research interest because changing the shape metals at nanoscale can provide access to materials with unique optical, electronic, and catalytic properties. The development seeded growth syntheses has provided researchers unprecedented anisotropic nanocrystals (particularly, gold, silver, platinum, palladium nanocrystals) precisely controlled dimensions crystallographic features. mechanisms by which various reagents present in...
Oriented aggregation is a special case of in which nanocrystals self-assemble and form new secondary single crystals. This process has been suggested to proceed via an intermediate state known as the mesocrystal, have parallel crystallographic alignment but are spatially separated. We present first direct observations mesocrystals with size shape similar product oriented aggregates by employing cryo-TEM directly image particles aqueous suspension. The images reveal that not only also...
Since the development of simple, aqueous protocols for synthesis anisotropic metal nanoparticles, research into many promising, valuable applications gold nanorods has grown considerably, but a number challenges remain, including gold-particle yield, robustness to minor impurities, and precise control nanorod surface chemistry. Herein we present results composite fractional factorial series experiments designed screen seven additional potential avenues understand seed-mediated...
Anisotropic nanoparticles are powerful building blocks for materials engineering. Unusual properties emerge with added anisotropy—often to an extraordinary degree—enabling countless new applications. For bottom-up assembly, anisotropy is crucial programmability; isotropic particles lack directional interactions and can self-assemble only by basic packing rules. have long fascinated scientists, their assembly behavior been the subjects of many theoretical studies over years. However, recently...
Gold nanorods have garnered a great deal of scientific interest because their unique optical properties, and they the potential to greatly impact many areas science technology. Understanding structure chemical makeup surfaces as well how tailor them is paramount importance in development successful applications. This Feature Article reviews current understanding surface chemistry as-synthesized gold nanorods, methods tailoring with various inorganic organic coatings/ligands, techniques...
Oriented aggregation is an important, nonclassical crystal growth mechanism that occurs in a wide array of materials, often producing nanoparticles with unique, anisotropic, and symmetry-defying morphologies. The acicular goethite (α-FeOOH) nanorods from ellipsoidal ferrihydrite (Fe5HO8·4H2O) was used as model system to study the effects sodium nitrate concentration on product morphology kinetics by oriented aggregation. Time-resolved sampling transmission electron microscopy were employed...
Phase transformation and particle growth are fundamental processes that govern final size morphology, as well phase composition. At the nanoscale, these can be significantly affected by initial size. Rates of anatase its to rutile increase with decreasing under hydrothermal conditions at pH 1 3. Overall, rates slower higher pH. 1, data fit a kinetic model developed based on dissolution–precipitation mechanism. However, 3, it deviates substantially from model, indicating occurs via different...
The kinetics of oriented aggregation are sensitive to solution conditions, including pH. Decreasing the difference between pH and point zero net proton charge results in an increasing second-order rate constant for nonclassical crystal growth by aggregation. Results discussed context Derjaguin Landau, Verwey Overbeek (DLVO) theory through use quantitative statistical comparisons. magnitude increase depends on primary particle size; however, trend size dependence deviate from predictions...
Mesoporous silica-coated gold nanorods (AuNR@MS) act as a colloidally stable Raman sensing platform with built-in analyte size cutoff.
Ultrafast transient absorption experiments and molecular dynamics simulations are utilized to investigate the thermal transport between aqueous solutions cetyltrimethylammonium bromide (CTAB)- or polyethylene glycol (PEG)-functionalized gold nanorods (GNRs). The measurement data interpreted with a multiscale heat diffusion model, which incorporates interfacial conductances predicted by dynamics. According our observations, effective conductance of GNR/PEG/water system is higher than that...
While many 3D structures of cation-coupled transporters have been determined, the mechanistic details governing obligatory coupling and functional regulations still remain elusive. The bacterial melibiose transporter (MelB) is a prototype major facilitator superfamily transporters. With conformation-selective nanobody, we determined low-sugar affinity inward-facing Na + -bound cryoEM structure. available outward-facing sugar-bound showed that N- C-terminal residues inner barrier contribute...
Cryogenic electron microscopy (cryo-EM) has emerged as a powerful tool for elucidating structures of dynamic macromolecular complexes, particularly those exhibiting compositional and conformational heterogeneity. The ability to capture multiple states within single experiment offers valuable mechanistic insights. However, challenges inherent sample preparation often necessitate changes initial standardized protocols. Issues such inadequate particle distribution, protein aggregation,...
Crystal growth by non-classical mechanisms, such as oriented aggregation, frequently involves an aggregation step. The of nanoparticles is sensitive to solution variables like ionic strength and pH, well the presence concentration other chemical species. Aggregation a critical first step during early stages aggregation. Time-resolved, cryogenic transmission electron microscopy was employed characterize degree reversibility influence additives on in aqueous suspensions. In this work, freshly...
Microfluidic sensing platforms facilitate parallel, low sample volume detection using various optical signal transduction mechanisms. Herein, we introduce a simple mixing microfluidic device, enabling serial dilution of introduced analyte solution that terminates in five discrete elements. We demonstrate the utility this device with on-chip fluorescence and surface-enhanced Raman scattering (SERS) analytes, use both when combined traditional inflexible SERS substrate SERS-active...
There is interest in the controlled aggregation of gold nanorods (GNRs) for production extended nanoassemblies. Prior studies have relied upon chemical modification GNR surface to achieve a desired final aggregate structure. Herein we illustrate that control electrolyte composition can facilitate end-to-end assembly cetyltrimethylammonium-bromide-coated (CTAB) GNRs. By adjusting either sulfate anion concentration or exposure time it possible connect GNRs chain-like assemblies. In contrast,...
The aggregation of suspended metal oxide and oxyhydroxide nanoparticles dramatically changes as a function solvent properties. In addition, selection can offer an additional parameter for controlling aggregative crystal growth (e.g., oriented aggregation). Here, results are presented demonstrating dramatic in the state goethite (α-FeOOH), anatase (TiO2), ferrihydrite (Fe5HO8·4H2O) changing solvents. Results discussed context Derjaguin Landau, Verwey Overbeek (DLVO) theory, dynamic light...
While many 3D structures of cation-coupled transporters have been determined, the mechanistic details governing obligatory coupling and functional regulations still remain elusive. The bacterial melibiose transporter (MelB) is a prototype major facilitator superfamily transporters. With conformation-selective nanobody, we determined low-sugar affinity inward-facing Na+-bound cryoEM structure. available outward-facing sugar-bound showed that N- C-terminal residues inner barrier contribute to...
Correction for 'In solution SERS sensing using mesoporous silica-coated gold nanorods' by Zhe Gao, et al., Analyst, 2016, 141, 5088-5095.
While many 3D structures of cation-coupled transporters have been determined, the mechanistic details governing obligatory coupling and functional regulations still remain elusive. The bacterial melibiose transporter (MelB) is a prototype Na + -coupled major facilitator superfamily transporters. With conformational nanobody (Nb), we determined low-sugar affinity inward-facing -bound cryoEM structure. Collectively with available outward-facing sugar-bound structures, both outer inner barriers...