Navigation Links
Study: Acidity can change cell membrane properties
Date:10/1/2013

Of all the amazing technologies humans have developed, none has matched the complexity of the fundamental building block of nature: the living cell. And none of the cell's activities would be possible without thin lipid membranes, or bilayers,that separate its parts and regulate their functions.

Understanding and controlling bilayers' properties is vital for advances in biology and biotechnology. Now an interdisciplinary team of Northwestern University researchers has determined how to control bilayers' crystallization by altering the acidity of their surroundings.

The research, published September 24 in the Proceedings of the National Academy of Sciences, sheds light on cell function and could enable advances in drug delivery and bio-inspired technology.

"In nature, living things function at a delicate balance: acidity, temperature, all its surroundings must be within specific limits, or they die," said co-author Monica Olvera de la Cruz, Lawyer Taylor Professor of Materials Science and Engineering, Chemistry, and (by courtesy) Chemical and Biological Engineering at Northwestern's McCormick School of Engineering. "When living things can adapt, however, they are more functional. We wanted to find the specific set of conditions under which bilayers, which control so much of the cell, can morph in nature."The research, published September 24 in the Proceedings of the National Academy of Sciences, sheds light on cell function and could enable advances in drug delivery and bio-inspired technology.Understanding and controlling bilayers' properties is vital for advances in biology and biotechnology. Now an interdisciplinary team of Northwestern University researchers has determined how to control bilayers' crystallization by altering the acidity of their surroundings.

By taking advantage of the charge in the molecules' head groups, the Northwestern researchers developed a new way to modify the membrane's physical properties. They began by co-assembling dilysine (+2) and carboxylate (-1) amphiphile molecules of varying tail lengths into bilayer membranes at different pH levels, which changed the effective charge of the heads. Bilayers are made of two layers of amphiphile molecules molecules with both water-loving and water-hating properties that form a crystalline shell around its contents. Shaped like a lollipop, amphiphile molecules possess a charged, water-loving (hydrophilic) head and a water-repelling (hydrophobic) tail; the molecules forming each layer line up tail-to-tail with the heads forming the exterior of the membrane. The density and arrangement of the molecules determine the membrane's porosity, strength, and other properties.

Then, using x-ray scattering technology at the DuPont-Northwestern-Dow Collaborative Access Team (DND-CAT) at Argonne National Laboratory's Advanced Photon Source, the researchers analyzed the resulting crystallization formed by the bilayers' molecules.

(To produce electron microscope images of membrane structures, researchers previously have frozen them, but this process is labor-intensive and changes the structural fidelity, which makes it less relevant for understanding membrane assembly and behavior under physiological conditions as carried out inside the human body.)

The Northwestern researchers found that most molecules did not respond to a change in acidity. But those that possessed a critical tail length a measure that correlates to the molecules' level of hydrophylia the charge of the molecules' heads changed to the extent that their two-dimensional crystallization morphed from a periodic rectangular-patterned lattice (found in more basic solutions) to a hexagonal lattice (found in more acidic solutions). Shells with a higher symmetry, such as hexagonal, are stronger and less brittle than those with lesser symmetry. The change in pH also altered the bilayers' thickness and the compactness of the molecules.

Changing the density and spacing of molecules within membranes could help researchers control the encapsulation and release efficiency of molecules inside a vesicle.


'/>"/>

Contact: Megan Fellman
fellman@northwestern.edu
847-491-3115
Northwestern University
Source:Eurekalert

Related biology news :

1. Penn study: Shutting off neurons helps bullied mice overcome symptoms of depression
2. Rutgers study: Worms may shed light on human ability to handle chronic stress
3. UT study: Chemical in antibacterial soaps may harm nursing babies
4. Study: Pedometer program helps motivate participants to sit less, move more
5. Study: MicroRNA cooperation mutes breast cancer oncogenes
6. Study: Environmental policies matter for growing megacities
7. Study: Widespread test-and-treat HIV policies could increase dangerous drug resistance
8. Study: Probiotics reduce stress-induced intestinal flare-ups
9. Study: Antibiotics are unique assassins
10. International study: Excess dietary salt may drive the development of autoimmune diseases
11. Influenza study: Meet virus new enemy
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:5/9/2016)... May 9, 2016 Elevay is ... to expanding freedom for high net worth professionals seeking ... today,s globally connected world, there is still no substitute ... ever duplicate sealing your deal with a firm handshake. ... by taking advantage of citizenship via investment programs like ...
(Date:4/28/2016)... BANGALORE, India , April 28, 2016 ... subsidiary of Infosys (NYSE: INFY ), and Samsung ... global partnership that will provide end customers with a ... and payment services.      (Logo: http://photos.prnewswire.com/prnh/20130122/589162 ... for financial services, but it also plays a fundamental part ...
(Date:4/26/2016)... India and LONDON ... Infosys Finacle, part of EdgeVerve Systems, a product ... and Onegini today announced a partnership to integrate ... solutions.      (Logo: http://photos.prnewswire.com/prnh/20151104/283829LOGO ... to provide their customers enhanced security to access ...
Breaking Biology News(10 mins):
(Date:5/23/2016)... and LONDON , May 23, 2016 ... Could See Frontage Boost Efficiency by 40% - Frontage ... - Frontage Enforce Quality, Compliance and Traceability Within the Bioanalytical ... with labs in the United States and ... to be deployed across its laboratory facilities. In addition to ...
(Date:5/23/2016)... ... 23, 2016 , ... Foresight Institute , a leading ... for the 2015 Foresight Institute Feynman Prizes. , These prestigious prizes, named ... for experiment and the other for theory in nanotechnology. Prof. Markus J. Buehler, ...
(Date:5/20/2016)... CA (PRWEB) , ... May 20, 2016 , ... The ... 10 of its most experienced veterinary clients have treated over 100 of their own ... edge technology to provide the highest level of care for their patients. , ...
(Date:5/20/2016)... NC (PRWEB) , ... May 20, 2016 , ... Korean ... suggesting that it may offer a new way to treat the disease. Surviving Mesothelioma ... it now. , Scientists from several Korean institutions based their mesothelioma study on ...
Breaking Biology Technology: