Navigation Links
New structural information on functionalization of gold nanoparticles
Date:8/2/2012

Nanometre-scale gold particles are currently intensively investigated for possible applications as catalysts, sensors, biolabels, drug delivery devices, biological contrast agents and as components in photonics and molecular electronics. The particles are prepared in a solution from gold salts and their reactive gold cores can be stabilized with various organic ligands. Particularly stable particles can be synthesized by using organothiol ligands that have a strong chemical interaction to gold, producing precise compositions in the size range of 1 to 3 nanometres. Modification of the protecting molecular overlayer is a key step in almost all applications. A detailed structural atomistic understanding of the processes of the exchange reaction has been lacking.

Now, professors Chris Ackerson in the Colorado State University in Ft. Collins, USA, and Hannu Hkkinen at the Nanoscience Center of the University of Jyvskyl, Finland, report the first structural study on the atomistic processes of a ligand-exchange reaction of a well-defined gold nanoparticle that has 102 gold atoms and 44 ligand sites in the molecular overlayer. The study was published in the Journal of the American Chemical Society on 21 July 2012 [1]. Prof. Hkkinen's work is funded by the Academy of Finland and prof. Ackerson's work is funded by the Colorado State University and the American Federation for Aging Research.

The studied particle has a chemical formula of Au102(p-MBA)44 and it was made by using a water-soluble thiol (para mercapto benzoic acid, p-MBA) as the stabilizing molecule. The X-ray crystal structure of this particle was first reported as the cover article of Science in 2007 by the group of Roger D. Kornberg from Stanford University [2]. Hkkinen led an international team of researchers that published a theoretical analysis of this and other thiol-stabilized gold nanoparticles in 2008 in the Proceedings of the National Academy of Sciences [3].

In the new study, Ackerson's group succeeded in making heterogeneous crystals of samples of Au102 particles that had undergone a ligand-exchange reaction where the p-MBA thiols in the molecular overlayer had been partially exchanged to a similar thiol containing a Bromine atom, the so-called para bromo benzene thiol (p-BBT), under a fast 5-minute reaction. The analysis of the heterogeneous crystals showed which ligand sites in the overlayer are the most likely to be changed during the short reaction time, i.e., from which sites the exchange process starts. Surprisingly, only 4 sites out of the 44 possibilities showed occupation by the exchanged ligand (see Figure). Theoretical analysis performed by Hkkinen's group gave insight into the atomistic details of possible reaction mechanisms. Evidence from experiment and theory indicates that the Au102(p-MBA)44 nanoparticle has a thiol overlayer where almost every thiol ligand site has its own reaction rate due to a highly heterogeneous structure of the overlayer. "The Au102(p-MBA)44 nanoparticle has a structure reminiscent of a protein, with a rigid inorganic gold core analogous to the alpha-carbon backbone of a protein core and chemically modifiable functional groups in the low-symmetry molecular overlayer", says prof. Ackerson. "When ligand exchange reactions are better understood, we hope to fully control the surface functionalization of the Au102 and similar water-soluble gold nanoparticles. The implications in biology for a fully controllable synthetic surface the size of a protein are profound", says prof. Hkkinen.


'/>"/>

Contact: Professor Hannu Hkkinen
hannu.j.hakkinen@jyu.fi
358-400-247-973
Academy of Finland
Source:Eurekalert  

Related biology technology :

1. UK research paves way to a scalable device for quantum information processing
2. GenoSpace Announces the Launch of a Cloud-Based "Information Ecosystem" for Advancing 21st-Century Personalized Medicine
3. "Biological Control Industry Overview: Companies & Products" Edition 2 is Here. Critical information for Understanding the Global Biopesticide/Biocontrol Market
4. Quammen Health Care Consultants Takes Over Information Technology Reins at Faith Regional Health Services
5. New England Biolabs Introduces Polbase, an Information Repository of Scientific Data for Polymerase Researchers
6. Gold nanoparticles could treat prostate cancer with fewer side effects than chemotherapy
7. Study improves understanding of surface molecules in controlling size of gold nanoparticles
8. Nanoparticles found in moon glass bubbles explain weird lunar soil behavior
9. Nanoparticles seen as artificial atoms
10. Light touch keeps a grip on delicate nanoparticles
11. New measuring techniques can improve efficiency, safety of nanoparticles
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
New structural information on functionalization of gold nanoparticles
(Date:6/23/2016)... ... June 23, 2016 , ... ... and Mold) microbial test has received AOAC Research Institute approval 061601. , “This ... introduced last year,” stated Bob Salter, Vice President of Regulatory and Industrial Affairs. ...
(Date:6/23/2016)...  The Biodesign Challenge (BDC), a university competition that ... living systems and biotechnology, announced its winning teams at ... New York City . The teams, ... at MoMA,s Celeste Bartos Theater during the daylong summit. ... curator of architecture and design, and Suzanne Lee ...
(Date:6/23/2016)... ... 2016 , ... Supplyframe, the Industry Network for electronics hardware ... . Located in Pasadena, Calif., the Design Lab’s mission is to bring together ... built and brought to market. , The Design Lab is Supplyframe’s physical representation ...
(Date:6/23/2016)... ... 23, 2016 , ... In a new case report published today in STEM ... who developed lymphedema after being treated for breast cancer benefitted from an injection of ... dealing with this debilitating, frequent side effect of cancer treatment. , Lymphedema ...
Breaking Biology Technology:
(Date:5/12/2016)... May 12, 2016 WearablesResearch.com , a ... the overview results from the Q1 wave of its ... wave was consumers, receptivity to a program where they ... a health insurance company. "We were surprised ... says Michael LaColla , CEO of Troubadour Research, ...
(Date:4/26/2016)... LONDON , April 26, 2016 ... EdgeVerve Systems, a product subsidiary of Infosys (NYSE: ... a partnership to integrate the Onegini mobile security ... (Logo: http://photos.prnewswire.com/prnh/20151104/283829LOGO ) The ... enhanced security to access and transact across channels. ...
(Date:4/14/2016)... Israel , April 14, 2016 ... Authentication and Malware Detection, today announced the appointment of ... assumed the new role. Goldwerger,s leadership appointment ... on the heels of the deployment of its platform ... BioCatch,s behavioral biometric technology, which discerns unique cognitive and ...
Breaking Biology News(10 mins):