Navigation Links
Microwave synthesis connects with the (quantum) dots
Date:6/12/2008

Materials researchers at the National Institute of Standards and Technology (NIST) have developed a simplified, low-cost process for producing high-quality, water-soluble "quantum dots" for biological research. By using a laboratory microwave reactor to promote the synthesis of the widely used nanomaterials, the recently published* NIST process avoids a problematic step in the conventional approach to making quantum dots, resulting in brighter, more stable dots.

Quantum dots are specially engineered nanoscale crystals of semiconductor compounds. The name comes from the fact that their infinitesimal size enables a quantum electronics effect that causes the crystals to fluoresce brilliantly at specific, sharply defined colors. Bright, stable, tiny and tunable across a broad spectrum of colors, quantum dots that are engineered to attach themselves to particular proteins have become a popular research tool in areas such as cancer research for detecting, labeling and tracking specific biomarkers and cells.

Making good quantum dots for biological research is complex. First a semiconductor compoundtypically a mixture of cadmium and seleniummust be induced to crystallize into discrete nanocrystals of just the right size. Cadmium is toxic, and the compound also can oxidize easily (ruining the effect), so the nanocrystals must be encapsulated in a protective shell such as zinc sulfide. To make them water soluble for biological applications, a short organic molecule called a "ligand" is attached to the zinc atoms. The organic ligand also serves as a tether to attach additional functional molecules that cause the dot to bind to specific proteins.

The accepted commercial method uses a high-temperature reaction (about 300 degrees Celsius) that must be carefully controlled under an inert gas atmosphere for the crystallization and encapsulation stages. An intermediate ligand material that can tolerate the high temperature is used to promote the crystallization process, but it must be chemically swapped afterwards for a different compound that makes the material water soluble. The ligand exchange stepas well as several variations on the processis known to significantly alter the luminescence and stability of the resulting quantum dots.

Seeking a better method, NIST researchers turned to microwave-assisted chemistry. Microwaves have been employed in a variety of chemical reactions to reduce the required times and temperatures. Working at temperatures half those of commercial processes, the group developed a relatively simple two-stage process that requires no special atmospheric conditions and directly incorporates the water-soluble ligand into the shell without an exchange step. Using commercially available starting materials, they have synthesized highly uniform and efficient quantum dots for a range of frequencies and shown them to be stable in aqueous solutions for longer than four months.


'/>"/>

Contact: Michael Baum
michael.baum@nist.gov
301-975-2763
National Institute of Standards and Technology (NIST)
Source:Eurekalert  

Related medicine news :

1. ThalesNano Inc. and the Christian Doppler Laboratory for Microwave Chemistry in Graz, Austria Collaborate on Flow Chemistry Technologies
2. MedWaves, Inc. Announces Receipt of United States Food and Drug Administration 510k Clearance to Market Its Patented Microwave Coagulation/Ablation System
3. Microwave treatments for enlarged prostate cause blood pressure surges
4. Herley Awarded $1 Million in Awards for Integrated Microwave Assemblies for U.S. Military Aircraft
5. Synthesis of natural molecule could lead to better anti-cancer drugs
6. Thomson Reuters Adds Routes of Synthesis Data to Its Newport Horizon Premium and Newport Vision Premium Solutions
7. Five Hospitals to Share Patient Data: ICW Connects Regional Medical Centers and University Facility
8. New Social Networking Website Connects Patients and Caregivers
9. AGD Advocacy Conference Connects General Dentists with Congress
10. Macerich Connects Women and Giving in Partnership with Step Up Womens Network
11. World Medical Tourism & Global Health Congress Connects Global Healthcare Providers with Global Insurance Companies
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Microwave synthesis connects with the (quantum) dots
(Date:10/13/2017)... (PRWEB) , ... October 13, 2017 , ... Many families ... However, many long-term care insurance companies have a waiver for care if the client ... elimination period, when the family pays for care, is often waived, so the benefits ...
(Date:10/13/2017)... ... October 13, 2017 , ... Talented host, actor ... on sciatica in a new episode of "Success Files," which is an award-winning ... innovation and investigates each subject in-depth with passion and integrity. , Sciatica occurs ...
(Date:10/12/2017)... ... 12, 2017 , ... CitiDent and San Francisco dentists, Dr. ... Oventus O2Vent technology. As many as 18 million Americans are estimated to suffer ... Oral appliances can offer significant relief to about 75 percent of people with ...
(Date:10/12/2017)... ... 2017 , ... Asante, a nationally recognized health system in ... existing home health joint venture through an agreement, effective October 1, 2017, to ... home health company with Asante, delivering clinically integrated care, for the past eight ...
(Date:10/12/2017)... , ... October 12, 2017 , ... On Saturday, October ... treadmill relay – Miles by Moonlight to raise money for the American Heart Association ... more. , Teams will work together to keep their treadmills moving for 5 ...
Breaking Medicine News(10 mins):
(Date:9/27/2017)... NEW YORK , Sept. 27, 2017  DarioHealth Corp. (NASDAQ: DRIO), ... solutions, today announced that its MyDario product is expected to appear on ... for when The Dr. Oz Show airs in your area: http://www.doctoroz.com/page/where-watch-dr-oz-show ... The nine-time Emmy award-winning, The Dr. ... ...
(Date:9/22/2017)... , Sept. 22, 2017 AVACEN Medical ... device is now successfully helping those with the widespread ... Fibromyalgia diagnosed Amanda in Essex, England ... and washing my hair, experiencing no sleep at all, ... painful spasm… I cannot recommend [the AVACEN 100] enough, ...
(Date:9/13/2017)... 13, 2017   OrthoAtlanta has been named the ... Host Committee (AFHC) for the 2018 College Football Playoff (CFP) ... at Mercedes-Benz Stadium in Atlanta, Georgia . ... "I,m In" campaign, participating in many activities leading up to, ... ...
Breaking Medicine Technology: