Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International

Wikipedia Affiliate Button

Home > Press > Nanocages for gold particles: what is happening inside?

Figure. Structure, metal immobilization, and chemical reaction inside a ferritin crystal. 
(a) Structure of the 24-mer ferritin molecule; (b) a ferritin monomer with the metal-binding sites; (c) a symmetric 3-fold axis channel; (d) preparation and crystallization of Au-containing ferritin; (e) cross-linking of the ferritin crystal and reduction of Au ions (yellow circles) into Au(0) atoms which form nanoclusters (brown particles).
Figure. Structure, metal immobilization, and chemical reaction inside a ferritin crystal. (a) Structure of the 24-mer ferritin molecule; (b) a ferritin monomer with the metal-binding sites; (c) a symmetric 3-fold axis channel; (d) preparation and crystallization of Au-containing ferritin; (e) cross-linking of the ferritin crystal and reduction of Au ions (yellow circles) into Au(0) atoms which form nanoclusters (brown particles).

Abstract:
Scientists at Tokyo Institute of Technology have used high-resolution crystallography to uncover the mechanism behind protein-assisted synthesis of gold nanoparticles, providing a platform for designing nanomaterials tailored for biomedical application.

Nanocages for gold particles: what is happening inside?

Tokyo, Japan | Posted on March 16th, 2017

In living organisms, free metal ions are stored and transported through proteins assembled into highly ordered structures such as protein cages via a reaction called biomineralization. This sophisticated biological strategy has attracted the attention of biotechnologists who speculate that natural ion-storage protein cages can be used to grow metal nanoparticles with desired properties.

Gold nanoparticles (AuNPs) are known for their excellent functions in catalysis, bioimaging, drug delivery, and therapy; therefore, the synthesis of AuPs with controlled sizes and shapes is very important for their application in nanomedicine. In protein scaffolds, AuNPs are formed by a sequential process involving Au deposition and agglomeration into small nanoclusters which act as nucleation centers for AuNP growth. However, the dynamic mechanism underlying the formation of Au nanoclusters in protein environments remains unclear.

To disclose molecular processes behind AuNP growth in protein nanocages, a group of biomolecular engineers at Tokyo Institute of Technology, led by Takafumi Ueno, used high-resolution crystallography and analyzed the formation of Au nanoclusters in ferritin. A universal intracellular iron-storage protein produced by almost all living organisms, ferritin forms a self-assembled 24-subunit nanocage with two specific metal-binding sites: the 3-fold axis channel and the accumulation center (Figure). Since Au ions have high affinity for sulfur, the scientists modified the accumulation center by introducing an additional sulfur-containing cystein residue to enhance Au uptake into the protein cage. Then, they reinforced Au-containing ferritin crystals by cross-linking in glutaraldehyde (Figure) to maintain their lattice structure. These modifications enabled the reduction of Au ions in the crystals and determination of binding positions of Au ions inside the ferritin cage by high resolution crystallography.

In the next step, the immobilized Au ions were reduced into Au(0) atoms using a reducing agent (NaBH4). As a result, the scientists could observe that the reduced Au agglomerated into nanoclusters formed in the 3-fold symmetric channels and in the metal accumulation centers (Figure), which was due to the gradual Au movement and conformational changes of surrounding amino acids.

The results obtained by Professor Ueno and his colleagues uncover the mechanism behind the formation of Au nanoclusters which are expected as nucleation centers for subsequent AuNP growth in the unique protein environment, providing a platform for future investigation of biomineralization and nanoparticle synthesis in biomolecular scaffolds.

Reference
Authors:
Basudev Maity, Satoshi Abe, and Takafumi Ueno
Title of original paper:
Observation of gold sub-nanocluster nucleation within a crystalline protein cage
Journal:
Nature Communications
DOI:
10.1038/NCOMMS14820
Affiliations:
Department of Life Science and Technology, Tokyo Institute of Technology

Correspondence to:

####

About Tokyo Institute of Technology
Tokyo Institute of Technology stands at the forefront of research and higher education as the leading university for science and technology in Japan. Tokyo Tech researchers excel in a variety of fields, such as material science, biology, computer science and physics. Founded in 1881, Tokyo Tech has grown to host 10,000 undergraduate and graduate students who become principled leaders of their fields and some of the most sought-after scientists and engineers at top companies. Embodying the Japanese philosophy of “monotsukuri,” meaning technical ingenuity and innovation, the Tokyo Tech community strives to make significant contributions to society through high-impact research.

For more information, please click here

Contacts:
Emiko Kawaguchi
Center for Public Affairs and Communications,
Tokyo Institute of Technology

+81-3-5734-2975

Copyright © Tokyo Institute of Technology

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Self-driving microrobots December 10th, 2019

CEA-Leti Thin-Film Batteries Target Extended Applications and Improved Performance in Medical Implants: IEDM 2019 Paper Reports Millimeter-Scale TFBs Exhibit the Best Performance In Both Energy and Power Densities December 10th, 2019

Arrowhead Pharmaceuticals Closes Underwritten Public Offering with Gross Proceeds of $266.8 Million December 7th, 2019

'Buildings' in human bone may hold key to stronger 3D-printed lightweight structures December 6th, 2019

Crystallography

How to trick electrons to see the hidden face of crystals: Researchers try a trick for complete 3D analysis of submicron crystals August 3rd, 2019

3-D-printed jars in ball-milling experiments June 29th, 2017

Novel nozzle saves crystals: Double flow concept widens spectrum for protein crystallography March 17th, 2017

Biophysicists propose new approach for membrane protein crystallization March 8th, 2017

Possible Futures

Self-driving microrobots December 10th, 2019

CEA-Leti Thin-Film Batteries Target Extended Applications and Improved Performance in Medical Implants: IEDM 2019 Paper Reports Millimeter-Scale TFBs Exhibit the Best Performance In Both Energy and Power Densities December 10th, 2019

'Buildings' in human bone may hold key to stronger 3D-printed lightweight structures December 6th, 2019

Artificial cells act more like the real thing December 6th, 2019

Self Assembly

"Inverse Design for Self-Assembly: Patchy Particles, Machine Learning, and the Truth about Entropy" December 3rd, 2019

Super-strong magnetic supercrystals can assemble themselves October 25th, 2019

A new way of making complex structures in thin films: Self-assembling materials can form patterns that might be useful in optical devices July 5th, 2019

University of Konstanz researchers create uniform-shape polymer nanocrystals: Researchers from the University of Konstanz's CRC 1214 'Anisotropic Particles as Building Blocks: Tailoring Shape, Interactions and Structures' generate uniform-shape nanocrystals using direct polymeriz June 14th, 2019

Nanomedicine

Arrowhead Pharmaceuticals Closes Underwritten Public Offering with Gross Proceeds of $266.8 Million December 7th, 2019

Artificial cells act more like the real thing December 6th, 2019

Arrowhead Pharmaceuticals Announces Pricing of Underwritten Public Offering of Common Stock December 5th, 2019

Arrowhead Pharmaceuticals Announces Proposed Underwritten Offering of Common Stock December 3rd, 2019

Discoveries

Artificial cells act more like the real thing December 6th, 2019

Scientists see defects in potential new semiconductor: Discovery could help in effort to make high-powered electronics more efficient December 5th, 2019

Electro-optical device provides solution to faster computing memories and processors: First-of-a-kind electro-optical device provides solution to faster and more energy efficient computing memories and processors December 2nd, 2019

Growing nano-tailored surfaces using micellar brushes November 29th, 2019

Materials/Metamaterials

Toward more efficient computing, with magnetic waves: Circuit design offers a path to 'spintronic' devices that use little electricity and generate practically no heat November 29th, 2019

NAUM’19 reviewed the increasing contribution of graphene nanotubes to sustainable development November 21st, 2019

Scientists probe the limits of ice: Transition between ice and liquid water gets fuzzy at the nanoscale November 9th, 2019

Disordered proteins become stable, 'super-sticky' materials: Improved protein control could lead to wound-healing gels and other applications November 3rd, 2019

Announcements

Self-driving microrobots December 10th, 2019

CEA-Leti Thin-Film Batteries Target Extended Applications and Improved Performance in Medical Implants: IEDM 2019 Paper Reports Millimeter-Scale TFBs Exhibit the Best Performance In Both Energy and Power Densities December 10th, 2019

Arrowhead Pharmaceuticals Closes Underwritten Public Offering with Gross Proceeds of $266.8 Million December 7th, 2019

'Buildings' in human bone may hold key to stronger 3D-printed lightweight structures December 6th, 2019

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers/Posters

Self-driving microrobots December 10th, 2019

'Buildings' in human bone may hold key to stronger 3D-printed lightweight structures December 6th, 2019

Artificial cells act more like the real thing December 6th, 2019

Scientists see defects in potential new semiconductor: Discovery could help in effort to make high-powered electronics more efficient December 5th, 2019

Nanobiotechnology

Arrowhead Pharmaceuticals Closes Underwritten Public Offering with Gross Proceeds of $266.8 Million December 7th, 2019

Artificial cells act more like the real thing December 6th, 2019

Arrowhead Pharmaceuticals Announces Pricing of Underwritten Public Offering of Common Stock December 5th, 2019

Arrowhead Pharmaceuticals Announces Proposed Underwritten Offering of Common Stock December 3rd, 2019

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project