Navigation Links
New windows opened on cell-to-cell interactions
Date:7/22/2009

Applying biological molecules from cell membranes to the surfaces of artificial materials is opening peepholes on the very basics of cell-to-cell interaction.

Two recently published papers by a University of Oregon biophysicist and colleagues suggest that putting lipids and other cell membrane components on manufactured surfaces could lead to new classes of self-assembling materials for use in precision optics, nanotechnology, electronics and pharmaceuticals.

Though the findings are basic, they provide new directions for research to help understand nature at nanotechnological scales where the orientation of minuscule proteins is crucial, said Raghuveer Parthasarathy, who is a member of the UO's Material Science Institute, the Institute of Molecular Biology and the Oregon Nanoscience and Microtechnologies Institute (ONAMI).

(Parthasarathy discusses his research at http://www.youtube.com/watch?v=XGOmp_fNVXQ, and he summarizes the studies described below at: http://www.youtube.com/watch?v=rvd7f6qYYro.)

Controlling interactions between colloidal materials

In the May issue of Soft Matter, a journal of the Royal Society of Chemistry, UO doctoral student Yupeng Kong and Parthasarathy applied biological material -- a thin layer of membrane lipids -- onto to tiny glass spheres about one-millionth of a meter in diameter to closely study colloidal interaction.

Colloids are tiny particles found dispersed in liquids: in milk, paints, many food stuffs, cosmetics and pharmaceuticals. Compared to atoms and molecules colloids are big, and creating artificial colloids with directed properties is a goal in many technologies, especially optics at nanoscales.

Before applying the biomembrane, the identical negatively charged spheres repelled each other. With the membrane attached, conditions changed dramatically. Suddenly, the like-charged spheres were attracted to each other.

"This was weird," Parthasarathy said. "Like-charged objects aren't supposed to attract each other. People have seen like-charge attraction in a few other colloidal systems in the last 10 or 15 years, but still no one understands it. Here, we've got the first system in which like-charge attraction can be controlled, simply by the incorporation of molecules from biological membranes. We can tune attraction or repulsion over the entire spectrum simply by changing the composition of the membrane. This is useful both for technological applications, and for illuminating the fundamental mechanisms behind colloidal interactions."

The observations were made using an inverted microscopy technique in which the glass spheres were placed in a 655-nanometer diode laser beam, an approach developed in Parthasarathy's lab by former undergraduate biophysics student Greg Tietjen, now a doctoral student at the University of Chicago.

The findings of the National Science Foundation-funded research, he said, suggest that specially tweaked biological membranes applied to artificially produced materials may serve as specialty control knobs that direct materials to do very specific things.

Controlling molecular orientation from cell membranes

In a paper appearing online in the Journal of the American Chemical Society (JACS) in early July, Parthasarathy teamed with organic chemists at the University of California, Berkeley, to study how molecules are oriented on their cell membranes to allow for cell-to-cell interactions.

The six-member research team built tiny artificial molecules that mimic brush-like membrane proteins and contain tiny fluorescent probes at the outer end. These miniscule polymers were incorporated into artificial membranes placed on a silicon wafer that acts like a mirror, allowing precise optical measurements of the orientation of the molecule.

Electron microscopy revealed the presence of rigid, rod-like brushy glycoprotein (sugar-containing compounds) -- 30 billionths of a meter long -- similar to natural cell-surface proteins. Interaction between cells occurs when these rods stand up from the membranes, a property whose control remains poorly understood.

The surprise, Parthasarathy said, was that the sugar-laden rods stood up like trees rising in a forest only for particular fluorescent probes, which represented just 2 percent of the molecule's weight.

The big issue that surfaced from the project -- funded by the U.S. Department of Energy, National Science Foundation and the Alfred P. Sloan Foundation -- was that the slightest trepidation of a molecule's structure affects its orientation, he said.

The goal, Parthasarathy said, may be to determine how to control the orientation of the brush-like forest through either chemical or optical measures to, in turn, control cell interaction. Such control of artificially produced molecules, he added, could have huge potential applications in the electronics industry.

Parthasarathy's UO team is now looking at DNA anchored to membranes to compare the findings and see if such on-off switching of the orientation of molecules may be possible.

"There are brush-like proteins at cell surfaces that are really important for such things as cellular interactions within the immune system," Parthasarathy said. "At the surface of every cell is a forest of molecules to induce interactions. These proteins need to rise from the forest. What allows them to stick up or lie down? We've really had a poor idea of what's going on. Knowing the genome and what proteins are there is crucially important, but that information in itself does not tell you anything about the answer to the question."


'/>"/>

Contact: Jim Barlow
jebarlow@uoregon.edu
541-346-3481
University of Oregon
Source:Eurekalert  

Related biology news :

1. Futronic Announces Microsoft Vista and Windows 2008 Server Support for Its Fingerprint Logon Software
2. Air-purifying church windows early nanotechnology
3. New, more direct pathways from outside the cell-to-cell nuclei discovered
4. Hidden interactions between predators and prey: evolution causes cryptic dynamics in ecology
5. Skin oil -- ozone interactions worsen air quality in airplanes
6. Keck Foundation funds study of biological interactions with nanomaterials
7. New technology illuminates protein interactions in living cells
8. Rong Li Lab reports protein interactions of MAP kinase signaling pathway
9. New Argonne study may shed light on protein-drug interactions
10. Stowers Proteomics Center devises method for assigning probabilities to human protein interactions
11. Workshop assesses interactions between climate, forests and land use in the Amazon Basin
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
New windows opened on cell-to-cell interactions
(Date:5/16/2017)... TEANECK, N.J. , May 16, 2017  Veratad ... leading provider of online age and identity verification solutions, ... the K(NO)W Identity Conference 2017, May 15 thru May ... Ronald Regan Building and International Trade Center. ... across the globe and in today,s quickly evolving digital ...
(Date:5/6/2017)... , May 5, 2017 ... just announced a new breakthrough in biometric authentication ... exploits quantum mechanical properties to perform biometric authentication. These ... smart semiconductor material created by Ram Group and ... finance, entertainment, transportation, supply chains and security. Ram ...
(Date:4/19/2017)... New York , April 19, 2017 ... competitive, as its vendor landscape is marked by the ... the market is however held by five major players ... Safran. Together these companies accounted for nearly 61% of ... of the leading companies in the global military biometrics ...
Breaking Biology News(10 mins):
(Date:10/10/2017)... Calif. , Oct. 10, 2017 SomaGenics ... from the NIH to develop RealSeq®-SC (Single Cell), expected ... for profiling small RNAs (including microRNAs) from single cells ... Program highlights the need to accelerate development of approaches ... "New techniques for measuring levels ...
(Date:10/10/2017)... ... 10, 2017 , ... The Pittcon Program Committee is pleased ... scientists who have made outstanding contributions to analytical chemistry and applied spectroscopy. Each ... leading conference and exposition for laboratory science, which will be held February 26-March ...
(Date:10/9/2017)... ... October 09, 2017 , ... The award-winning American Farmer television series ... 2018. American Farmer airs Tuesdays at 8:30aET on RFD-TV. , With global population ... challenge of how to continue to feed a growing nation. At the same time, ...
(Date:10/9/2017)... ... October 09, 2017 , ... The ... medical marijuana products targeting the needs of consumers who are incorporating medical marijuana ... place in Phoenix, Arizona. , As operators of two successful Valley dispensaries, The ...
Breaking Biology Technology: