NANOTECHNOLOGY/LIGHT ACTIVATION: IR light method turns blood clotting on (like drugs) and off (like nothing else)

Gold nanoparticles, controlled by infrared (IR) light from a pulsed femtosecond laser, promise to promote wound healing and help doctors control blood clotting in patients undergoing surgery.1

Blood clotting results from a long chain of protein interactions, which eventually form fibrin, a fibrous protein that seals wounds. Heparin and other blood thinners interfere with this process by targeting reactions that occur during the blood-clotting cascade, but reversing the effects of such drugs requires removing them from the bloodstream. A better solution, says Kimberly Hamad-Schifferli, a technical staff member of the Lincoln Laboratory at the Massachusetts Institute of Technology (MIT; Cambridge, MA), is an agent that targets only the last step: the conversion of fibrinogen to fibrin.

A colorized electron micrograph shows red blood cells with gold nanorods (yellow dots) on their surfaces. The blue represents a fixing polymer. (Image courtesy of Helena de Puig)

This last step is a reaction mediated by an enzyme called thrombin. Earlier research showed that DNA with a specific sequence inhibits thrombin by blocking the site where it would typically bind fibrinogen. The complementary DNA sequence can shut off the inhibition by binding to the original DNA strand and preventing it from attaching to thrombin.

Hamad-Schifferli and colleagues had previously demonstrated that gold nanorods can enable the release of drugs or other compounds when activated with IR light, and the size of the nanorod determines the wavelength of light that will activate it. To manipulate the blood-clotting cascade, she decided to load a 35-nm-long nanorod with the DNA thrombin inhibitor and 60 nm rod with the complementary DNA strand. But the researchers found they couldn't load enough DNA onto each particle to make this process effective. By soaking the nanorods in a solution of human serum protein and the DNA molecules, however, they found they were able to attach six times more DNA than through chemical bonding. Now, when the nanorods are exposed to the correct wavelength of light, electrons within the gold melt slightly and release their DNA payload.

In tests using donated blood, the researchers found that the particles successfully turned clotting on and off in all samples. But to make the particles practical for use in patients, they would need to be targeted to the site of injury, which the researchers are now working on doing. Once they reached the site, they would need to be within a few millimeters of the skin surface for the IR light shone on the skin to reach them.

The researchers are also working to modify the system so particles can be activated using a continuous-wave (CW) laser, which is smaller and less powerful than the laser they are currently using.

1. H. de Puig, A. Cifuentes Rius, D. Flemister, S.H. Baxamusa, and K. Hamad-Schifferli, PLoS ONE, 8, 7, e68511 (2013); doi:10.1371/journal.pone.0068511.

Get All the BioOptics World News Delivered to Your Inbox

Subscribe to BioOptics World Magazine or email newsletter today at no cost and receive the latest news and information.

 Subscribe Now

Get All the BioOptics World News Delivered to Your Inbox

Subscribe to BioOptics World Magazine or email newsletter today at no cost and receive the latest news and information.

 Subscribe Now
Related Articles

Microscopy helps discover potential new drug target for cystic fibrosis

An international team of scientists, using automated microscopy and genetics, have discovered a promising potential drug target for cystic fibrosis.

Next-gen DNA sequencing helps provide new genetic clue to anorexia

The largest next-generation DNA sequencing study of anorexia nervosa to date has linked the eating disorder to variants in a gene coding for an enzyme that regulates cholesterol metabolism.

Synchrotron light identifies RNA double helix structure

Scientists at McGill University have crystallized a short RNA sequence, poly (rA)11, and used data collected at the Canadian Light Source (CLS) and the Cornell High Energy Synchrotron to confirm th...

OpGen opens clinical services laboratory, launches genetic tests offering for HAIs

Genetic analysis company OpGen has launched a clinical services laboratory that will focus on developing genetic tests and analysis services for the surveillance and identification of healthcare-as...

GENOMICS/AUDIOLOGY: Massively parallel DNA sequencing IDs causes of deafness

Genetic mutations are a major cause of hearing loss in developed countries: At least half of all infants who become deaf can trace their conditions to mutations, as can many people who develop prog...

Next-generation DNA sequencing could ID nearly all genetic causes of deafness

Next-generation DNA sequencing technologies are enabling the identification of deafness-causing genetic variants, say researchers from the University of Miami Miller School of Medicine.

Researchers to present optical techniques for counting single viruses outside the lab

Two separate teams of researchers have developed new optical methods for determining the exact viral load of a sample by counting individual virus particles.

Multiplexed detection system from Genalyte garners CE mark approval

Genalyte's Maverick multiplexed detection system, which simultaneously analyzes multiple antibodies and other proteins from a single small sample, is now CE-marked in Europe for research use.

X-ray laser determines protein structure

An international team of researchers, including Lawrence Livermore National Laboratory (LLNL; Livermore, CA) physicist Matthias Frank and postdoctoral researcher Mark Hunter, have for the first tim...

BLOGS

Neuro15 exhibitors meet exacting demands: Part 2

Increasingly, neuroscientists are working with researchers in disciplines such as chemistry and p...

Why be free?

A successful career contributed to keeping OpticalRayTracer—an optical design software program—fr...

LASER Munich 2015 is bio-bent

LASER World of Photonics 2015 included the European Conferences on Biomedical Optics among its si...

White Papers

Understanding Optical Filters

Optical filters can be used to attenuate or enhance an image, transmit or reflect specific wavele...

How can I find the right digital camera for my microscopy application?

Nowadays, image processing is found in a wide range of optical microscopy applications. Examples ...

CONNECT WITH US

            

Twitter- BioOptics World

Copyright © 2007-2015. PennWell Corporation, Tulsa, OK. All Rights Reserved.PRIVACY POLICY | TERMS AND CONDITIONS