Dedicated to the acceptance, medical treatment, & legal protection of individuals in the process of correcting the misalignment of their anatomical sex, & supporting their transition into society.
Oxford, UK. People who haven't been there often talk about corrective surgery as though new genitals are "reshaped" or "fashioned" to achieve an approximation of the "real" thing....
New York, NY, USA. Transition costs money. In the US, pre-op individuals have virtually no medical coverage for hormone treatment, Sex Reassignment Surgery (SRS), and related procedures. Those who are employed...
New York, NY, USA. Despite the central role of psychotherapy in the practice of psychiatry throughout its history, a declining number of office-based psychiatrists appear provide psychotherapy to their pat...
New York, NY, USA. A new survey finds widespread dissatisfaction with the US health care system. The Commonwealth Fund [N1] released the results and a companion report from The Commonwealth Fund Commissio...
Chapel Hil, NC, USA. A meta-analysis of 23 published studies, including data from more than 30,700 women worldwide, shows that women with bacterial vaginosis (BV) — the most common type of vaginosis in women of...
Milwaukee, WI, USA. The need to translate basic science discoveries into the clinical arena is widely acknowledged, but grant applications that support clinical science receive less positive peer reviews than t...
Boise, ID, USA. Reducing breast discomfort before a mammography exam is a simple matter of applying pain-relieving gel. The results from a clinical trial to be published in the print journal Radiolog...
London, UK. To reinvigorate medicine and provide a useful information tool for clinicians and patients
Why would anybody want to publish a journal that is a mountain of case reports? Aren't case...
Tempe, AZ, USA. Miners have used a canary in a cage to warn of gas, an example of a biosensor. The miners used an organism that responded to threshold levels of toxic substances to warn us of their presence. Strictly speaking, a biosensor is a device that combines a biological component with a physicochemical detector component. Nanotechnology applies science and technology to control matter on the atomic and molecular scale. What can happen if we combine both concepts?
A biosensing nanodevice developed by Arizona State University (ASU) researchers has the potential to improve health screenings for diseases like anthrax, cancer and antibiotic resistant Staphylococcus aureus (MRSA).
Single-molecule detection of DNA via sequence-specific links between F1-ATPase motors and gold nanorod sensors. Justin York, David Spetzler, Fusheng Xiong and Wayne D. Frasch. Lab Chip, 2008, 8, 415-419, DOI: 10.1039 / b716744j.
[ Download Tech Supp PDF ] [ See Tech Supp Movie (.avi) ]
[ Hear The Canary Sing ]
Generally, nanodevices are biological engines measured on the order of molecules100 nanometers or smaller. The ASU device is based is the world's tiniest rotary motor. Based on the enzyme F1-adenosine triphosphatase (F1- ATPase), it is only 10–12 nanometers in diameter. It has an axle that spins and produces torque.
Developed by ASU researcher Wayne Frasch and hs colleagues, the tiny machine is part of a complex of proteins key to creating energy in all living things, including photosynthesis in plants. F1-ATPase breaks down adenosine triphosphate (ATP) to adenosine diphospahte (ADP), releasing energy. Previous studies of its structure and characteristics have been the source of two Nobel Prizes awarded in 1979 and 1997.
It was through his own detailed study of the rotational mechanism of the F1-ATPase, which operates like a three-cylinder Mazda rotary motor, that Frasch conceived of a way to take this tiny biological powerhouse and couple it with science applications outside of the human body.
What Frasch and his colleagues show is that the enzyme can be armed with an optical probe (gold nanorod) and manipulated to emit a signal when it detects a single molecule of target DNA. This is achieved by anchoring a quiescent F1-ATPase motor to a surface. A single strand of a reference biotinylated DNA molecule is then attached to its axle. The marker protein, biotin, on the DNA is known to bind specifically and tightly to the glycoprotein avidin, so an avidin-coated gold nanorod is then added. The avidin-nanorod attaches to the biotinylated DNA strand and forms a stable complex. [Ed.: Please refer to the Technical Supplement download for details.]
When a test solution containing a target piece of DNA is added, this DNA binds to the single complementary reference strand attached to the F1-ATPase. The DNA complex, suspended between the nanorod and the axle, forms a stiff bridge. Once ATP is added to the test solution, the F1-ATPase axle spins, and with it, the attached (now double-stranded) DNA and nanorod. The whirling nano-sized device emits a pulsing red signal that can then be detected with a microscope.
Detection of DNA using the nanodevice.
(A) Sequential steps in nanodevice assembly.
(B) Composition of the nanodevice.
(C) Manifestation of rotation. A blinking red and green spot indicates the presence of a single molecule of DNA.
According to Frasch, the rotation discriminates fully assembled nanodevices from nonspecifically bound nanorods, resulting in a sensitivity limit of one zeptomole (600 molecules). Simply put, if it's not moving and flashing, it simply isn't relevant. [Ed.: Please refer to the Technical Supplement movie download for an example.].
Moreover, Frasch says, "Studies with the F1-ATPase in my laboratory show that since it can detect single DNA molecules, it far exceeds the detection limits of conventional PCR [polymerase chain reaction] technology." Such a detection instrument based on the F1-ATPase enzyme would also be "faster and more portable."
With support from the Science Foundation Arizona (SFAz), Frasch will transfer his work from the bench to biotech, through establishment of a local company that utilizes the nano-sized F1-ATPase to produce a DNA detection instrument.
A prototype of the DNA detector is already in development. It is roughly the size of a small tissue box. Sampling would be as simple as taking a swab from an infected wound or a piece of baggage, dissolving it in a solution and placing a drop on a slide bearing reference F1-ATPases and their nanorods. Once in the instrument, red blinking signals emitted by rotating nanorods would let a computer know there's trouble, literally, in a flash.
SSFAz funding has also enabled Frasch to extend the method to do protein detection at the single molecule level. This is novel because, unlike DNA, proteins can not be amplified artificially to improve the chances of detection.
"Rapid and sensitive biosensing of nucleic acids and proteins is vital for the identification of pathogenic agents of biomedical and bioterrorist importance," notes Frasch, who is also with the Center for Bioenergy and Photosynthesis (CB&P) in the College of Liberal Arts and Sciences. "It also provides a new avenue through which to analyze genotypes and forensic evidence."
Single-molecule detection of DNA via sequence-specific links between F1-ATPase motors and gold nanorod sensors. Justin York, David Spetzler, Fusheng Xiong and Wayne D. Frasch. Lab Chip, 2008, 8, 415-419, DOI: 10.1039 / b716744j. [ Download Tech Supp PDF ] [ See Tech Supp Movie (.avi) ] [ Hear The Canary Sing ]
Abstract
We report the construction of a novel biosensing nanodevice to detect single, sequence-specific target DNA molecules. Nanodevice assembly occurs through the association of an immobilized F1-ATPase molecular motor and a functionalized gold nanorod via a single 3,5-dibiotinylated DNA molecule. Target-dependent 3,5-dibiotinylated DNA bridges form by combining ligation and exonucleation reactions (LXR), with a specificity capable of selecting against a single nucleotide polymorphism (SNP). Using dark field microscopy to detect gold nanorods, quantitation of assembled nanodevices is sufficient to distinguish the presence of as few as 1800 DNA bridges from nonspecifically bound nanorods. The rotary mechanism of F1-ATPase can drive gold nanorod rotation when the nanorod is attached via the DNA bridge. Therefore, rotation discriminates fully assembled devices from nonspecifically bound nanorods, resulting in a sensitivity limit of one zeptomole (600 molecules).
The TS-Si News Service is a collaborative effort by TS-Si.org editors, contributors, and corresponding institutions. The sources can include the cited individuals and organizations, as well as TS-Si.org staff contributions. Articles and news reports do not necessarily convey official positions of TS-Si, its partners, or affiliates.
We welcome your comments. Use the form below to leave a public comment or send private correspondence via the TS-Si Contact Page. We will not divulge any personal details or place you on a mailing list without your permission.
Crazy Sexy Cancer. This is the trailer for a documentary film by Kris Carr about her cancer adventure. It premiered on TLC and Discovery Health (Fall 2007).
Kris also authored two books, Crazy Sexy Cancer Tips and Crazy Sexy Cancer Survivor: More Rebellion and Fire for Your Healing Journey.
Developed by ASU researcher Wayne Frasch and hs colleagues, the tiny machine is part of a complex of proteins key to creating energy in all living things, including photosynthesis in plants. F1-ATPase breaks down adenosine triphosphate (ATP) to adenosine diphospahte (ADP), releasing energy. Previous studies of its structure and characteristics have been the source of two Nobel Prizes awarded in 1979 and 1997. 
What Frasch and his colleagues show is that the enzyme can be armed with an optical probe (gold nanorod) and manipulated to emit a signal when it detects a single molecule of target DNA. This is achieved by anchoring a quiescent F1-ATPase motor to a surface. A single strand of a reference biotinylated DNA molecule is then attached to its axle. The marker protein, biotin, on the DNA is known to bind specifically and tightly to the glycoprotein avidin, so an avidin-coated gold nanorod is then added. The avidin-nanorod attaches to the biotinylated DNA strand and forms a stable complex. [Ed.: Please refer to the Technical Supplement download for details.]
Subscribe to this comment's feed
Show/Hide comments
Show/Hide comment form
Copyright © 2005-2008 TS-Si, Inc. • Except where noted, this site is licensed under a Creative Commons Attribution-NoDerivs 2.5 License. • Some rights reserved. • TS-Si is a nonprofit organization dedicated to the acceptance, medical treatment, & legal protection of individuals in the process of correcting the misalignment of their anatomical sex, & supporting their transition into society.