UV light controls antibodies, improves biosensors

October 31, 2011
One UV photon is absorbed by the antibody and the disulfide bridge is opened, thereby forming thiol groups. Their interaction with the gold surface leads to an oriented Fab region so that the upside down position (circled in the right side of the picture) is hampered and the antigen binding is more effective. Credit: Biomedical Optics Express

From detecting pathogens in blood samples to the study of protein synthesis, Quartz Crystal Microbalance (QCM) sensors have many uses in modern biology. In this technique, antibodies anchored to gold electrodes on a piece of quartz crystal act like the "hooks" on the sticky side of a Velcro strap, grabbing molecules of interest as they pass by. The more molecule-sensing antibodies on the surface of the sensor, the more sensitive the QCM device's detection capabilities.

Unfortunately, some of the typically anchor themselves to the gold plate "hook"-side-down, rendering them useless as bio-receptors and dampening the sensor's sensitivity. Now researchers from the University of Naples "Federico II" and the Second University of Naples in Italy have found a way to increase the number of right-side-up antibodies in this well-established molecule detection process – using light.

In a paper recently published in the Optical Society's open-access journal Biomedical Optics Express, the team of scientists irradiated antibodies with ultra-short pulses of ultraviolet (UV) light. The UV light is absorbed by the amino acid tryptophan, which breaks the disulfide bridges holding parts of the antibody together and causes a particular part of the amino acid cysteine, called a thiol group, to become exposed at the tail end of the antibody.

Because thiol groups are more strongly attracted to the gold electrodes than other parts of the antibody, the bottom sides of these irradiated antibodies become much more likely to adhere to the gold electrodes than the "hook" ends. Using this method, the researchers were able to more than double the sensitivity of the QCM device, opening up new possibilities for research using this type of sensor, the researchers say.

Explore further: UV light improving chances of fighting cancer

More information: "Light assisted antibody immobilization for bio-sensing," Biomedical Optics Express, Della Ventura et al., Vol. 2, Issue 11, pp. 3223-3231 (2011).

Related Stories

UV light improving chances of fighting cancer

October 30, 2007

Scientists at Newcastle University have developed a cancer fighting technology which uses UV light to activate antibodies which very specifically attack tumours.

Scientists Find Rare, Potent Antibody to HIV-1

February 23, 2009

(PhysOrg.com) -- Scientists at Duke University Medical Center have for the first time isolated an important antibody in human serum that could potentially play a key role in the design of an AIDS vaccine. The research appears ...

Researchers develop method that aims to stabilize antibodies

September 3, 2009

(PhysOrg.com) -- Researchers at the U.S. Department of Energy's Argonne National Laboratory have developed a systematic method to improve the stability of antibodies. The technique could lead to better biosensors, disease ...

Recommended for you

ATLAS and CMS experiments shed light on Higgs properties

September 1, 2015

Three years after the announcement of the discovery of a new particle, the so-called Higgs boson, the ATLAS and CMS Collaborations present for the first time combined measurements of many of its properties, at the third annual ...

Tiny drops of early universe 'perfect' fluid

September 1, 2015

The Relativistic Heavy Ion Collider (RHIC), a particle collider for nuclear physics research at the U.S. Department of Energy's (DOE) Brookhaven National Laboratory, smashes large nuclei together at close to the speed of ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.