Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Targeted drug delivery now possible with ’pHLIP’ peptide

13.04.2006
Scientists at Yale and the University of Rhode Island report the development of a peptide that can specifically and directly deliver molecules to the inside of cells like a nanosyringe, creating a new tool for drug delivery, gene control and imaging of diseased tissues.

Their "cargo carrier" peptide called pHLIP, for pH (Low) Insertion Peptide, accumulates in the membranes of cells in acidic environments and spontaneously transfers attached molecules across the membrane. The cargo is then released by cleavage of a sulfur-sulfur bond that is only unstable if it is inside the cell. The study, published early online in the Proceedings of the National Academy of Sciences, was led by Donald M. Engelman, professor of molecular biophysics and biochemistry at Yale.


The delivery of fluorescent phalloidin into cells by pHLIP. (a) HeLa cells at pH 7.4 (Left) shows weak label localized at the cell membrane, and pH 6.5 (Right) shows fluorescent actin filaments inside cells. (b) HeLa (Left), breast cancer (Center), and prostate cancer (Right) cells show different and characteristic patterns of fluorescent actin filaments. Credit: Credit: Yale University

"Our system offers a new technology for the fast and efficient delivery of drugs, imaging probes, or cell and gene regulation agents into living cells," said Engelman. "pHLIP may provide a new approach for imaging, diagnosis and treatment of diseases with naturally occurring or artificially created low-pH extracellular environments, such as tumors, infarcts, stroke-afflicted tissue, atherosclerotic lesions, sites of inflammation or infection, or damaged tissue resulting from trauma."

Normal cells are surrounded by an environment with a constant pH of about 7.4, while tumor cells and sites of inflammation actively pump protons out and create an acid extracellular pH of 5.5 to 6.5.

The study shows that pHLIP entry into the cell membrane and the translocation of molecules into cells are not mediated by the usual entry pathways -- endocytosis, interactions with cell receptors, or by formation of pores in cell membranes.

"By translocating a molecule into a cell and releasing it in the cytoplasm, pHLIP functions, in effect, as a nanosyringe," according to Engelman. "The peptide does not exhibit any of this structure in solution or on the cell membrane at neutral pH. However, at low pH it becomes rigid like a syringe needle, inserts into a cell membrane, and injects molecules into cells.

Drug or dye molecules can be linked by sulfur-sulfur bonds to pHLIP. This paper demonstrates the effectiveness of pHLIP with a cargo of fluorescently tagged phalloidin, a toxin from the deadly Amanita phalloides mushroom that normally cannot enter cells. Inside the cells phalloidin binds to actin molecules and "freezes" the cellular skeleton giving a distinct visual pattern under the microscope.

Janet Rettig Emanuel | EurekAlert!
Further information:
http://www.yale.edu
http://www.yale.edu/ocr/

More articles from Life Sciences:

nachricht Scientists unlock ability to generate new sensory hair cells
22.02.2017 | Brigham and Women's Hospital

nachricht New insights into the information processing of motor neurons
22.02.2017 | Max Planck Florida Institute for Neuroscience

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Microhotplates for a smart gas sensor

22.02.2017 | Power and Electrical Engineering

Scientists unlock ability to generate new sensory hair cells

22.02.2017 | Life Sciences

Prediction: More gas-giants will be found orbiting Sun-like stars

22.02.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>